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Tip - cichlidfish.net
PLUMBING ≈ FRESHWATER PLUMBING Portable Water Systems Water System Refits Installation Tips Maintenance Grey Water & Seawater Plumbing Seacocks, Thru-hulls & Valves Bilge Plumbing Scupper Plumbing 2 3 6 6 8 8 10 12 1 0 1 Archives / ≈ ADDING A WATER HEATER 13 ≈ RX FOR HEADS HEADS: The front end of the sanitation system DISPOSAL: The back end of the system Step-by-Step Head Rebuild Add a holding tank Odor Control MoreRoutine Maintenance Head Troubleshooting Chart 15 15 16 17 18 20 21 22 ≈ BUILD A MADE-TO-MEASURE HOLDING TANK 23 ≈ INSTALL A PRESSURE-WATER SYSTEM Reduce plumbing system noise 25 26 ≈ KEEPING DRY BELOW DECKS Types of Bilge Pumps Pump Performance Determining Pump Size System Planning Emergency Only Pumps Installation Guidelines Automatic Pump Switches 28 28 28 29 29 30 31 34 ≈ HOSE CLAMPS - BUYER BEWARE 35 ≈ EASY-TO-INSTALL BILGE PUMP ALARM 36 ≈ BILGE PUMP REPLACEMENT 37 ≈ WHAT YOU SHOULD KNOW ABOUT MARINE HOSE 38 ≈ HOW TO PLUMB BENDS 41 © DIY boat owner 2001 1-888-658-2628 Subscribe / Help / Quit PLUMBING 101 By Nick Bailey If you, like most DIY readers, own an older boat and are inclined towards self-reliance, you already know that plumbing seems to account for more than its fair share of trouble among the onboard systems. It’s the little things — all those fittings that leak, pumps that won’t, potable water that isn’t, diabolical heads that always clog or smell, a seized gate valve or broken thruhull (with sea water rushing in!) — little, nasty things that can ruin your whole day. And, it’s the surveyor’s emphatic disapproval of your scupper hoses or the holding tank that is about to explode because the vent is clogged. “Run for your lives. It’s a bomb!” Furthermore, because the boatbuilder originally installed many of these items before the deck went on or the twin V-8s were wedged in, you can’t even reach the offending parts, let alone fix them. Never mind. If you have the plumber’s prerequisites of grim determination, double- / Back page / Next page / Contents page / jointedness, a colorful vocabulary and a basic tool kit, as well as immunity from claustrophobia, muscle cramps and the everpresent bilge slime (get a tetanus shot), you are ready to take up arms against any plumbing problem. This article will cover plumbing for potable, gray and sea water, and bilge and scupper systems. We’ll discuss waste systems, holding tank retrofits and head maintenance in our next issue. POTABLE WATER SYSTEMS Potable water systems range in complexity from a single, small tank hooked to a manual pump in the galley to multi-fixture hot-andcold-water pressure systems on larger yachts that can even include washing machines and ice makers (Figure 1). Around 1970, typical equipment consisted of monel (most common) and some galvanized tanks and copper plumbing, often with a big Jabsco diaphragm pressure pump at the heart of the system. In the case of larger powerboats, a 24- or 32volt DC electrical system was often the norm. Faucets and fixtures were not much different from what you would find at home. Smaller boats (under 10.5m/35’), especially sailboats, typically were not fitted with pressure water systems. Throughout the 70s and into the 80s, however, as boatbuilders encountered greater consumer demand for “luxury” systems, pressure water, hot water and many other comforts of home became more commonplace. Nowadays, those “comforts” are usually standard equipment in boats over 9m (30’). Galvanized tanks gave way to experiments with integral tanks in fiberglass boats (not always such a great idea) and then to the off-the-shelf plastic (polyethylene) tanks commonly used today. Copper plumbing was replaced by reinforced vinyl “clear braid” / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 2 PLUMBING 101 / Back page / Next page / Contents page / MANUAL COLD WATER SYSTEM SINGLE- OR TWIN-FIXTURE COLD WATER (DEMAND PUMP) b a Vanity Galley *Manual pumps Vanity Fill Fill Vent Vent *Pump type: Manuak or foot pump. Some can also be combines with an electric pump as in (b) MULTI-FIXTURE COLD PRESSURE WATER SYSTEM c *Electric pump located below tank level MULTI-FIXTURE HOT & COLD PRESSURE WATER SYSTEM d Vanity Aft Shower Galley Vanity *Pump type: Centrifugal or impeller, may or may not run dry, most not self-priming. Water Tank Water Tank Galley Fill Fill Vent Momentary switch Galley Optional Accumulator Pressure Switch Water Tank * Electric Pump Vent Nick Bailey Cold **Accumulator Tank * Pump type: Same as multi fixture (d), but can be smaller capacity. Filter Ice Maker Optional Hot Engine Coolant Pressure switch *Electric Pump Filter **Accumulator optional but recommended Hot Water Heater *Pump type: Self priming, cam run dry (i.e. diaphram type). Figure 1 Sample water systems. A) manual cold-water system B) single- or twin-fixture cold-water system (demand pump) C) multifixture cold pressure water system D) multi-fixture hot-and-cold pressure water system. hose which, in turn, gave way to semi-rigid plastic pipe — often with proprietary self-clamping fittings such as the Whale System 15, FlairIt, Qest or Serkit systems. Reciprocating diaphragm pumps are still popular, though they are being gradually replaced by rotary multi-lobe diaphragm pumps such as the Flojet Quad II (the originator), Groco P-9000, Jabsco Par-Mate or Par-Max, SHURflo Silencer and Whale Evenflo pumps. These pumps are usually quieter and less expensive, yet offer the same ability to run dry without damage and self prime that is characteristic of traditional diaphragm pumps. Water at the touch of a button is also available in simple coldwater systems by fitting an in-line “demand” centrifugal pump that can stand alone or “flow through” and supplement an existing manual pump. Before proceeding with any upgrades or repairs, however, check your water system in detail to verify hose or pipe sizes (Figure 2), the size and style of fittings and the exact model of your electric pump, if you have one. Refits Most water systems leave room for improvement, whether it’s / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 3 PLUMBING 101 / Back page / Next page / Contents page / upgrading a cold-water pressure system to full hot and cold water or simply installing an in-line primary filter before the pressure pump. (This filter will eliminate problems due to debris jamming the valves; any pressure system without one is bound to be troublesome.) Here are some other upgrades worth considering: Modern rotary multi-lobe diaphragm pumps, like The Silencer from SHURflo, are quiet, can run dry without damage and are self-priming. Courtesy of West Marine with a new rotary-type pump. These are much quieter and some manufacturers offer an inexpensive rebuild kit for the old pump. Figure 2 The following chart shows how dimensions compare on various sizes of straight tailpieces. Note that the hosebarb end of the tailpiece (A) measures the same as its listed size, unlike the pipe end (C) which is not related. (Courtesy of West Marine.) Size A 1/2" 1/2" 3/4" 3/4" 1" 1" 1-1/4" 1-1/4" 1-1/2" 1-1/2" B C D 5/16" 13/16" 2-1/4" 1/2" 1" 2-1/4" 13/16" 1-5/16" 2-1/2" 1" 1-5/8" 2-3/4" 1-1/4" 1-7/8" 3" smooth out water delivery and stop the annoying rapid on/off cycling of the pressure pump. 2/ Replace the pressure pump 3/ Add a shower, whether it’s a cold-only or a hot-and-cold-water system, a cockpit or swim-platform shower is guaranteed to be a popular addition to any pressure water system, especially after you’ve been swimming in salt water. Complete kits are available from several manufacturers (Attwood, Heater Craft and Whale are just a few examples). The kits incorporate a neat, recessed well for the mixer assembly. Just make a cutout in the cockpit wall or transom and tee into your existing plumbing. Make sure you know what you are cutting into — you’ll want to miss fuel and water tanks, wiring, piping, or structural stringers — and that you have enough room to run the plumbing. 4/ Replace old faucets and mixers. Many attractive units designed specifically for boats are now available (Barka, Scandvik, SHURflo, Tempo and Whale are popular makes). 5/ Add a secondary water filter. A variety of in-line activated charcoal filters are now available that can improve your water by reducing the impurities that cause bad taste and odors. Most of these filters won’t eliminate bacteria by themselves and must be used in conjunction with antibacterial tablets or additives or another filter. One exception is the New World filter (#7054), which uses a three-stage filtering process to remove bacteria. Another filter unit, the Water Fixer, also uses UV light to sterilize the - Ti p Emergency Plugs You should always have on board a collection of tapered softwood (pine or cedar) plugs sized to jam into a failed hose, a broken CPS (Cheap Plastic S!*t) thru-hull or when you have to disconnect a hose and the valve won’t close. Corro-sion can lead to sudden failure of a fitting, as can a lightning strike. A lanyard threaded through the plug is wrapped around the base to keep water pressure from pushing out the plug. These plugs are the ultimate plumber’s helper. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 Anne-Marie Hendry 1/ Add an accumulator tank. This is an air-filled tank connected to the discharge side of the pump. It will 4 PLUMBING 101 water. If you’ve got a case of really stinky water, drain and sanitize the system first (see Maintenance on page 6). Water Fixer also sells an in-line UV chamber that’s easily retrofitted in a boat already equipped with a filtration system. 6/ Electrify your manual water system. Option 1: Whale and Jabsco offer small, in-line pumps complete with manual switches that can either work through your manual pump or replace it. This is a simple installation (though the centrifugal non-self-priming pumps have to go below tank level) and this type of pump won’t be damaged if it happens to be switched on when the faucet is closed. Option 2: By adding the appropriate faucets and, if necessary, upgrading the hose and fittings on your system, it’s fairly easy to install a pump complete with an automatic pressure switch and convert to the convenience of a pressure water system. 7/ Add a manual backup. Install a manually-operated pump in a pressurized water system to ensure / Back page / Next page / Contents page / that water can be drawn in the event of a power failure. Tee the hose for the hand pump upstream of the pressure pump. 8/ Add a deep sink. Older boats with shallow, oval-shaped sinks are easily retrofitted with deeper high-quality stainless steel rectangular ones or double sinks; on some installations the two basins may be the same dimensions as a single. 9/ Install a tank monitor. These units use everything from the oldfashioned dip stick to pressure, sonar or electric sensors to read the fluid level in the tank. Most work well in water or fuel but are unreliable in a holding tank. One of the more dependable units, the Tank Tender from Hart Systems, operates on air pressure. You simply pump air into the tank and a gauge reads the amount of pressure in inches of liquid. And since there’s no wiring involved, these units are easy to install. The all-new electronic Tank Scan from Northern Research can monitor up to five tanks by means of a sonar sensor mounted on the outside of each tank, eliminating the need to cut into the tank. General Installation Tips Flojet’s 2840 with a Quad II rotary diaphragm pump and accumulator tank mounted on a plastic base makes a compact package for pressurized water installations on larger boats. Any plumbing work leads you into the question: “What size is it and will this fit to that?” Finding the answers to these questions is not made any easier by the fact that on any given size of NPT (National Pipe Thread) fitting there isn’t any threaded part actually measuring that size (Figure 2). Hose-barb diameters generally measure at their nominal size but nominal sizes for hose are based on the inside diameter and bear no relationship to the outside dimension. On the other hand, pipe sizing is roughly based on the outside diameter. Make sure the hose or pipe you use is food grade (garden hose is not Replacing old faucets and mixers with new, more-stylish designs is a worthwhile upgrade. acceptable). Clear PVC hose is fine for cold-water non-pressure systems. Clear braid reinforced PVC hose is okay in hot-and-cold pressure systems and is the least expensive. Many argue that despite their higher cost, semi-rigid pipe systems are the easiest of all to install. Installation requires few tools (Figure 3) and you won’t have to struggle to jam stiff hose over barb fittings or fiddle with hose clamps. Soften the hose in hot water, then rub a small amount of dish detergent or Vaseline on as a lubricant, or heat the hose end evenly with a hair dryer until it softens. Semi-rigid pipe won’t kink as easily, either. If you do use semirigid pipe, however, plan very carefully and be prepared to order the fit tings in advance; few retailers are likely to have everything you need in stock. Make sure all pumps are wired following the manufacturer’s directions and are fused properly. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 5 PLUMBING 101 So you don’t have pressure water and don’t want to mess with your shorepower or engine. In that case, Nautical Innovations’ new Hot Springs Water Heater may be what you need. It’s a plastic non-pressure-rated 15-litre (US 4gallon), 12-volt heater that uses a 100-watt DC element (8-amp draw). This unit promises lukewarm to very warm water, 32°C to 40°C (90°F to 105°F), with a three-hour to overnight recycling time, depending on the temperature of the cold water going in. It’s connected as an auxiliary tank by selector valve to a non-pressure system. This will provide a couple of foot-pump showers plus dishwashing daily and is well within the maintenance level of a small battery charger (keep an eye on your battery electrolyte levels). At US$200, it’s a lot more civilized than a solar-heated “sun” shower water bag. Atlantic Marine also offers a 100-watt DC element for its T Series stainless-steel heater, best fitted in the 15- litre (US 4-gallon) model. This heater can be used in a pressure system and has an optional engine heat exchanger (US$439 and up). With wiring and plumbing, neatness counts. Seawater hoses should be top-quality fabric or wire-reinforced rubber. It’s good practice to doubleclamp hoses (this is not always possible) with clamps of all-stainless steel (including the screw) fastened so the screws are staggered (Figure 4). (The double-clamp rule applies to all exhaust and fuel-fill connections and, if possible, seawater 2 1 FIRST PUSH PIPE FULLY INTO FITTING UP TO LINE THEN INSERT U-CLIP TO LOCK PIPE INTO FITTING MEASURE LENGTH OF TUBING REQUIRED FROM THIS POINT. ENSURE END OF PIPE IS CUT SQUARE. TO REMOVE PIPE PUSH COLLAR IN 3 4 SNAP COVER INTO POSITION TO PREVENT THE U-CLIP COMING LOOSE AND RELEASING PIPE CROSS SECTION SHOWING THE CLAMPING SYSTEM WHICH FORMS AN EASILY DISMANTLED LEAK-PROOF JOINT Figure 3 Whale System 15 semi-rigid pipe system is easy to install and requires no tools. 1 Measure length of tubing required from this point. 2 Insert U-clip to lock pipe into fitting. 3 Snap cover into position to prevent the U-clip coming loose and releasing pipe. 4 Cross-section showing the clamping system which forms an easily dismantled leak-proof joint. connections mounted less than 15cm (6”) above the waterline.) To prevent leaks when the hose and adapter fit poorly, or to seal existing leaks, apply sealant to the adapter only (Figure 5); do not apply to the inside of the hose. Don’t use any toxic sealants like 3M 5200 or other polyurethane adhesive to seal leaks in a potable water system. Using sealants will make the removal of the hose for maintenance or replacement very difficult. Where a hose passes through a bulkhead or partition, you’ll need to provide chafe protection. Use a rubber grommet (if you can find one the right size) or split a short length of oversize hose, wrap it around the system hose where it passes through the bulkhead and secure with tape or hose clamps. For complex piping systems, it’s a good practice to draw up a circuit diagram showing the location of hose runs, seacocks, connections and wiring terminals. File this in your maintenance log for quick reference when doing routine servicing or repairs. Maintenance Given proper winterizing, a potable water system should not need much maintenance other than the occasional water-pump service or repair and finding and fixing the odd leak. If there are foul odors, or if the system becomes contaminated, disinfect it American Boat and Yacht Council Hot H20 DC Alternative / Back page / Next page / Contents page / Figure 4 Proper hose clamp installation. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 6 PLUMBING 101 / Back page / Next page / Contents page / American Boat and Yacht Council temperature. If the water turns blue, it may be unsafe to drink; drain the tank and rinse it using the method outlined above or another chlorinebased water treatment. Figure 5 To prevent or seal existing leaks when the hose and adapter fit poorly, apply a non-toxic sealant to the adapter only but take note: using sealants will make the removal of the hose very difficult. using standard household bleach (typically a 5.25% sodium hypochloride solution). Exact instructions are given in the American Boat and Yacht Council (ABYC) standards manual, appendix H-23; here’s a brief description of the sanitization treatment for water systems. (Keep in mind that bleach may be tough on rubber pump parts and it should never be used in heads.) Step 1: Flush the system with potable water and drain it completely. Step 2: Fill the system completely with chlorine at 100 parts per million and allow to stand for one hour. Step 3: Drain and flush thoroughly with fresh water. Step 4: Refill with potable water. If the tank still smells like bleach, you haven’t flushed it enough. You should also check your tank regularly for bacteria with a watertesting kit such as WaterCheck. Simply pour water into the bag and let it sit for 24 to 36 hours at room Rust is another common maintenance problem on older boats or steel boats with integral metal tanks. Corrosion eventually overcomes the galvanizing or epoxy coatings, first causing rusty water and then causing the tank (or hull) to leak. If replacement of the tank is not practical, it may be possible to gain access inside, grind or blast the corroded steel to “near bright metal” and apply a potable epoxy coating (white Devo Barrust 235, available from marine and industrial paint suppliers, can be used in this application). If the steel cannot be reached to be properly prepped, however, you’ll waste your time trying to apply coatings over a bad surface. If there’s even the slightest pinhole in the epoxy liner, the tank will start to rust and eventually leak again. In that case, it’s time to think in terms of an auxiliary tank located elsewhere in the boat, or to consider major repairs — such as cutting out the tank and replacing it with a stainless-steel one. A flexible “bladder” tank (they’re available in many sizes) or a custom-made epoxy-coated plywood tank fitted inside the old integral tank is also a viable option. Polyethylene tanks that have cracked can sometimes be repaired successfully; replacement, however, is the best option. Pressure Water-Pump Repairs Rebuild kits with detailed instructions are available for most high-end pressure water pumps; Adding a water filter will improve water quality, reducing bad taste and odors. This Water Fixer unit also utilizes a UV light chamber to sterilize the water. lower-cost pumps may not be worth the bother. The most common complaint is that the pump runs but doesn’t pump; this is usually caused by debris in the one-way valves and dismantling and cleaning is all that is needed. If the pump won’t run, check the voltage to the pump. If there’s no problem with the voltage, the motor may be dead or the pressure switch may be malfunctioning. Using inadequate wire gauges or too-small-diameter hose will both cause motor burnout. Try shorting across the switch to see if the pump runs. If it does, replace the pressure switch. If the pump runs for a bit and then pops the breaker, you could have a bad pump motor, a weak breaker or a blocked waterline. Disconnect the waterline and try it again, then check the line for blockage. If the pump runs on and is not shut off normally by the pressure switch, you either have a big leak - Ti p - Filler ‘er up To prevent the heating element in the hot water tank from burning out when you recommission your boat, fill the tank with water before turning on the power. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 7 PLUMBING 101 - Ti p CONSERVE WATER Use seawater for clean-up jobs in the galley. If your boat has a washdown system, tee off the discharge side of the pump and hook up the hose to a manual pump or a kitchen-type sprayer mounted in a convenient place in the galley. or the pressure switch is faulty. If the pump cycles frequently, you have a leak you’ll need to find. If the system is leak-free, replace the switch. If the lights dim when the pump goes on, either the pump is drawing too much current and you’ll need to upgrade the wire size or you’ve got a defective pump motor, a blocked waterline or a weak breaker. GRAY WATER AND SEAWATER PLUMBING Gray Water Gray water is any waste water other than the sewage from your head. Typically, galley and vanity sink drains are connected via hose to a valved thru-hull fitting (“seacock”) and the gray water drains out the bottom of the boat. This works fine as long as your sink is well above the waterline. Sailboats have another problem. The sink that is above the waterline when the boat’s at anchor may not be when you’re sailing upwind with the boat heeled 20°. Owners of such boats soon get into the habit / Back page / Next page / Contents page / of shutting off the seacock when the sink is not in use; forgetting to do so is not conducive to domestic harmony — and adds unnecessarily to the excitement of cruising. When the drain is below the waterline, as it often is with a shower or in sinks in deep-draft vessels, you must collect the waste water and pump it overboard. I have seen instances where the whole bilge served as the collection point for gray water. With any extended use, however, you will end up with bilge reek not dissimilar to that in an 18th Century frigate. That may sound romantic, but it isn’t, especially if some among the crew are already feeling a bit green. A better option is a small, easily cleaned collection sump, or a tank with its own automatic or manuallyswitched submersible or selfpriming diaphragm pump. This sump accepts drain hoses from one or more fixtures. While showering or draining a sink, you switch on the sump pump and the pump’s discharge overboard will usually stay ahead of the incoming flow of waste water. Better yet, if the pump has a float switch, it will turn itself on. Any submersible pump or pickup strainer in the sump or gray water tank will require occasional cleaning to remove hair and other debris, so you must be able to gain easy access to the sump. SEACOCKS, THRU-HULLS AND VALVES In general, hull “skin fittings” and the hose systems connected to them are critical components, whether they are draining waste water out or letting fresh water in. The following anecdote provides an example of some of the little things that can sink you. In the summer of ‘75 in Toronto, Ont., the influential owner of a new 9m (30’) sailboat built by a well-known and reputable Canadian manufacturer received a call from his downtown marina. It seemed that his boat had inexplicably sunk at its mooring. After salvage, the builder’s representatives discovered that the threads on the white metal nut holding the galley sink tailpiece in place had been machined a bit too thin and the nut (a 65-cent item) had split, letting the now disconnected sink drain hose and tailpiece fall just below the waterline (glub, glub, glub). Subsequent boats from this manufacturer all have a piece of wire holding up the tailpiece and a little tag on the companionway drop board that reads “Good seamanship dictates that all seacocks be closed when leaving the boat.” This was a lesson learned — fortunately, no one was put in danger during the learning. You should carefully check your own below-waterline hardware and think about things that might cause a sinking. Hoses should be top quality, securely clamped and replaced immediately if they become cracked or weathered. Hose clamps should be all-stainless. Seacocks, thru-hulls and valves should be fiber-reinforced plastic (such as RC Products Marelon fittings by Forespar), or bronze or stainless, but never brass nor CPS (Cheap Plastic S!*t!). Many boats sink every year from thru-hulls made of delrin or CPS. Impending failure is evidenced by cracking and crazing on the outside flange. Often, the thru-hull is sealed with a / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 8 PLUMBING 101 HANDLE PACKING NUT MAIN BODY NUT THREADED ROD TO RAISE AND LOWER GRATE Jim Sollers SLOT IN VALVE BODY Figure 6 Gate valves fail without warning — they seize easily, the stem breaks if forced and debris prevents the gate from closing. Replace all valves below the waterline with quarter-turn ball valves. non-compatible sealant that attacks the plastic. Better to replace all CPS thru-hulls. Seacocks should be quarterturn ball valves because they are faster acting and less likely to seize. Gate valves (Figure 6), recognizable by the “tap” handle that is turned to open or close the valve, are a poor choice on a boat since you can’t tell at a glance if they are open or closed. Furthermore, the gate that raises and lowers inside the valve as the Figure 7 Marelon fittings are better than bronze units as they don’t corrode and require less maintenance. / Back page / Next page / Contents page / handle is turned can easily be prevented from seating properly by debris, the valve seizes easily and the stem is easily broken off if forced. A worthwhile upgrade project is to replace all gate valves with quarter-turn ball valves. When you’re installing new or replacement seacocks or valves, be sure their operation isn’t hindered by other fixtures or hardware and that they are easily accessed for maintenance. Marelon fittings (Figure 7) have been on the market now for many years and, in many ways, are as good as bronze units with the bonus feature of being immune to galvanic corrosion — the grim reaper of any underwater metal. Be careful which way and with how much torque you apply to a Marelon handle or it will break. Keep a few spares on board. Tip: If a Marelon valve jams, back off the large assembly nut until the handle turns (about one turn), then slowly retighten the nut while turning the handle until you feel resistance. Seawater (raw water) is often in demand on board — for engine cooling, head flushing, galley prewash rinsing, deck washing, air-conditioner cooling and so on. If you are adding a new seawater fixture, avoid the temptation to tee it off the engine intake. This could cause your engine coolant pump to suck air at a critical moment and overheat (leaving you with an expensive repair). You can safely tee off your gray-water outlets, though you may find your new pump clogged with hair or bits of galley trash. Our next issue will look at the particular requirements to handle seawater without siphoning and overflow of the head. If your head is below the waterline, this again can cause sinking. - Ti p REVERSING THE FLOW For sailboaters only: Does water flow into the sink via the drain when your boat heels — either when sailing or grounding — rather than out of the sink? Install a one-way check valve in the drain hose. Maintenance All seacocks and valves need yearly lubrication and inspection. The traditional seacock has the thru-hull and valve as a single unit utilizing a tapered plug and seat either in-line or at right angles to the axis of the seacock. The plug has a hole in it which lines up with the outlet in the seat when the seacock is open. Such units have a lot of moving metal surface in contact and can get very stiff if not well greased. At least once a season, disassemble each seacock and lubricate and repair as necessary. BILGE PLUMBING The bilge pump is on one hand a convenience and on the other a critical safety system. There are a surprising number of boats that rely on their bilge pumps — planked wooden boats that never quite took up after launch; runabouts with leaky covers and badly scuppered cockpits; inboards and auxiliaries with dribbling stuffing boxes; and many others. If left unattended and not pumped they either promptly sink or sink after the first all-day rainstorm of the season. Many people rely on their / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 9 PLUMBING 101 automatic electric bilge pump to keep their boats afloat without even being aware they’re doing so. This is a dangerous position to be in because, sooner or later, every bilge pump stops working. (Of course, working in the marine service industry may cause my opinions to be biased; I don’t get to see the reliable pumps!) Float switches jam or fail, batteries dry out or go flat, pumps burn out or are clogged with debris or rust which never sleeps. If you are planning to install an electric bilge pump consider the following. There are basically two types: submersible centrifugalstyle pumps (from Attwood, Depco, Groco, Lovett, Mayfair, Rule, SHURflo, Vetus and others) and non-submersible self-priming diaphragm types (such as the Flojet LF-12) with a strum box or screened pickup in the bilge. All bilge pumps require some kind of strainer or screen to prevent fouling of the impeller in the cage of the submersible unit or the oneway valves in the diaphragm pumps. Either type can be controlled by an automatic switch or manually triggered. The nonsubmersible unit has an advantage if access into the deepest part of the bilge is difficult (in deep-V boats, for example). The submersible has the advantages of lower cost and, in some big models, very high flow rates. Both types can run dry safely, although the submersible pump bearings will eventually overheat if they become dry. Lovett pumps are the only submersible units that are UL approved, meaning they meet minimum vibration, shock and safety requirements. Bilge pumps must be mounted / Back page / Next page / Contents page / on a flat surface and fastened securely with self-tapping screws, a good underwater adhesive or by clamping them to a bulkhead or stringer. Refrain from using the corrugated hose typically sold for bilge-pump use. The price is right but the corrugations slow down the discharge rate — according to Tom Hale, technical director of ABYC, the hose reduces outflow by as much as 40%. The smooth “cuffs” on the ends located every foot or so also don’t allow enough room for two clamps. Smoothwalled reinforced PVC hose (as flexible as you can find) that won’t kink or crush when it’s stepped on is a better choice. Be sure the pump is wired correctly — hot wire is brown, ground lead is black. Wiring must be secured with cable ties and connections should be made well above the water level in the bilge. Short leads from the pump often make this impossible and you’ll need to use adhesive-lined heat-shrink terminals. (See DIY 1998 #4 for complete crimping instructions.) Consider using these anyway to ensure connections are impervious to water sloshing about in the bilge. When choosing a pump, keep in mind how far the pump must push the water upwards before it goes over the side. Remember that nominal flow rates are based on zero lift or a zero head discharge rate. Installation factors — the type of hose and number of bends, how far the pump must push the water, the height of the thru-hull fitting — all affect flow rates. A fair lift is often required. This consideration is critical when you’re deciding where to put the discharge fitting of any bilge pump so water won’t drain back into the boat under any Corrugated hose typically sold for bilge-pump use is cheap, but the corrugations slow down the discharge rate and heavy tools or a carelessly placed foot will crush it. circumstances. Water reversal is a common problem in many boats that immerse the above-thewaterline thru-hull; the thru-hull is covered underway, causing a back siphon, and the bilge floods with water when the pump shuts off. To prevent backflowing, loop the discharge hose high above the waterline; don’t use a one-way check valve which can trap crud and restrict flow. Unfortunately, either solution reduces a pump’s discharge capacity and they are only effective where the thru-hull is - Ti p A BAD FIT Double-clamped hose connections are best but sometimes the fitting on the pump is not long enough to fit completely under the backup (outer) clamp. When this happens, don’t tighten the clamp so much that it partially collapses the hose. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 10 PLUMBING 101 installed a minimum of 20cm (8”) above the waterline. On sailboats, the measurement is taken when the boat is heeled; installation is usually only possible when the discharge hose exits at the transom near the centerline. Where the thru-hull is mounted closer to the waterline you need to provide an anti-siphoning valve at the top of the loop or an air vent. This can be accomplished by teeing into a cockpit drain or into a shower discharge. All tees must be high above the waterline. Various automatic switches are available, from simple tilting floats that usually contain a switch triggered by liquid mercury (these can jam and foul) to air-pressure types (more reliable) and even sonic and electronic sensors (definitely more expensive; maybe more reliable). Regardless of the sophistication of an electric pump system or even an engine-driven pump, power can fail and every boat should have at least one high- Every boat should have at least one high-capacity manual bilge pump as a backup. / Back page / Next page / Contents page / capacity manual bilge pump as a backup. (And, a large bucket! It’s said that there is no manual bilge pump better than a frightened boater with a bucket and this is probably true but, at that stage, you are probably better off sending out a Mayday call on the VHF while pumping with the other hand!) These are positive displacement diaphragm pumps. Diaphragm pumps are rugged, can pass some debris and solids and are available in a variety of sizes. They can be installed internally with a deck plate or in the open on a bulkhead. Units are available from Henderson, Edson, Rule, Vetus and Whale. If you own a small boat don’t skimp on the pump size.Remember that given the same 2.54cm (1”) hole in a hull, a small boat will fill and sink a lot faster than a large one. When fighting a leak, you need all the time you can get. Maintenance Bilge pumps don’t need much maintenance. Simply keep the float switches and the bilge clean and free of debris and oil which can damage the rubber parts in most pumps. (Remember that submersible units generally have to be replaced when they fail, with the exception of the higher-end Lovett pump — all of whose components, be it a set of belts, switch or motor, are fully replaceable in the event of a failure. And that brings us to the ultimate bilge pump: the wet or dry vacuum (Shop Vac). Granted, it only runs on shorepower, but it’s the only pump that will get every last drop of water out of your bilge. Try it sometime! In our Thunderbird sailboat fleet it is considered essential equipment. In Lovett bilge pumps are the only submersible units that are UL approved and have replaceable parts. an emergency situation,a valuable alternative to a bilge pump is to use the intake hose of the engine cooling water pump. Debris in the bilge can plug the engine, so you’ll need to attach a strainer (screen) to the hose end. SCUPPER PLUMBING Power- or sailboats with large open cockpits often come from the factory with woefully underengineered scupper drains. Consider this worst-case scenario: a disabled or slow-moving boat in a following sea suddenly pooped and swamped by a big breaking wave. Would your boat survive this? Lots of big scuppers in the cockpit are a good thing. If possible, have them drain above the heeled waterline or you must install seacocks. If your cockpit is so deep that it is close to or below the waterline, any drains will have to go to seacocks installed in the bottom of the hull. Sailboats with deep teeshaped cockpits have particular problems because when they heel the scuppers are just as likely to pump water in as let it out. Oneway flapper valves can help. Often the hoses are crossed from one side to the other so that the / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 11 PLUMBING 101 port drain goes to the starboard thru-hull or vice versa. This keeps the low-side thru-hull connected to the high-side drain and everything stays dry. This style of hose arrangement can be a liability during winter storage in northern climates, however, as it’s difficult to avoid low spots that trap water in the hose. This water may freeze and block the scuppers or, worse, pop the hose off the drain fitting allowing the boat to fill up with water over the winter. (A good leak-free tarp is recommended.) Powerboats have their own scupper problems. For example, there is a scupper system on a deep-V sportboat built by a reputable manufacturer that is / Back page / Next page / Contents page / supposed to drain the cockpit and engine hatches to a series of shallow aluminum channels. These channels lead to a thru-hull and flapper valve an inch or two above the at-rest waterline on both sides. If a twig, leaf or other small debris were to lodge in the oneway valve, forcing it to open, and if two people stood to one side of the cockpit, water would happily flow back into the boat and into the engine compartment. Yes, the boat will sink at the dock once the bilge pump quits. I’ve seen it happen. This type of scupper system needs serious reworking. Maintenance Scupper hoses should be of the same high quality as others below the waterline and should be replaced if they become cracked or degraded. Follow the same maintenance procedure for seacocks or valves below the waterline as you would for those above. Nick Bailey has been in the marine service profession for more than 20 years and currently is service manager of Bristol Marine in Mississauga, Ont. He and his wife own and race a wooden Thunderbird that recently underwent a major refit. Watch for an article detailing some of their renovations in our next issue. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 12 PLUMBING 101 / Back page / Next page / Contents page / Adding a Water Heater before use are usually fired by propane, are less common on boats and are beyond the scope of a do-it-yourself article. Work with explosive propane and the handling of combustible gases should be left to a licensed gas fitter. In a similar vein, if you are not familiar with the basic 110-volt wiring required to hook up your hot-water heating element, you should seek the assistance of someone who is experienced. At the very least, have your connections checked prior to plugging in the heater. When planning the layout of the system, especially the tank location, try to arrange a close look at the same model boat already equipped with a factoryinstalled system — and copy it where that’s practical. Or you can contact the builder (if they’re still in business) for guidelines. A professional-looking “stock” installation will always raise the resale value of your boat. You do, however, have the freedom to AVOID THIS TABBING STRINGER AVOID THIS OK American Boat and Yacht Council If you live and cook aboard for longer that the occasional weekend cruise, hot running water is more than a convenience. The good news is that if your boat has a 110-volt shorepower system and cold water, you’re already halfway to a hot-water system. There are two completely different approaches to the problem: a storage-tank heater or a flow-through “demand” heater. The former is the most common type of system. It has a storage tank very similar to a household unit but with a smaller capacity. Heat is usually provided at dockside by a 1,500-watt 110-volt AC heating element and, while underway, by hot engine coolant recirculating through a heat exchanger in the tank. Units are available from Atlantic Marine, Raritan, Seaward and others. Never install a household water heater which is not ignition protected and could spark and cause a fire. Demand heaters that do not store water but heat it immediately install more deluxe fixtures should your budget allow it. The tank will need to sit on a level surface so a solid 19mm (3/4”) plywood epoxy-painted shelf will need to be prepared and screwed or fiberglass tabbed into place (see Figure 8). Once the tank is shoehorned into place (usually a tight fit in a cockpit locker or in the engine room) and fastened securely, run your cold water (in) and hot water (out) lines with hose. For the “hot” side, good quality clear-braid PVC hose is pressure-rated at 65°C (150°F) and connects the traditional way with adapters and double clamped. (Make sure the Figure 8 Before cutting or drilling anything when running piping, check on each side of the bulkhead or partition to ensure you don’t cut into structural stringers or tabbing that hold the bulkhead in place. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 13 WATER HEATER / Back page / Next page / Contents page / Equipment list: Description Cost 6-gallon (typically) hot-water tank (may not include engine coolant heat exchanger and a place to put it!) 15-amp breaker $350-$600 $25 14-gauge multi-strand boat cable $1.37 per foot Replacement mixer for galley (or additional single faucet) $20-$100 Mixer for vanity (plus optional shower) and shower sump and pump $20-$100 Hose or pipe sufficient to go from heater to galley and vanity $10-$100 Tee for cold-water line, miscellaneous fitting connectors, elbows, clamps $20-$100 clamps are tight, but not so tight they cut into the hose. If you see particles of hose squishing through the cracks in the clamp, you’ve destroyed the hose.) An even better choice is semi-flexible plastic pipe, which is more durable, less prone to kinks and usually has fittings that are less likely to leak and easier to assemble. Threading piping through the boat is time-consuming and fiddly work. Access is often difficult and you will probably have to drill many holes through bulkheads. Be very careful! Before cutting or drilling anything, check on each side of the bulkhead or partition to ensure you don’t cut into a tank, wiring or other piping, or structural stringers or tabbing that hold the bulkhead in place (Figure 8) . Fasten the plumbing every few feet with cable clamps or wire ties and try to keep it out of the bilge to prevent contamination. Avoid tight bends that can kink hose; instead, install a 90° elbow. The tee connection to the cold-water system can be made anywhere downstream of the pressure pump and before the first fixture. Hot water heaters need a check valve, either at the water inlet to the tank or at the tee connection so the hot water cannot flow back into the cold water. Make sure you have one. You may have to remove the sink to get access for your connections to the mixer or faucet. Provide for easy access to the tank, fittings and all connections for maintenance. Any 110-volt wire used should be at least 14-gauge copper multistrand boat cable and must be sized to the amperage and wattage of the heater; depending on the routing, you may need 12 or 10 gauge. Household singlestrand cable is not safe in a boat because engine vibration and jarring from when the boat slams into waves fatigues the wire, leading to breaks and shorts and fires. The hot (black) wire connects to one terminal of the element and the neutral (white) wire connects to the other. Ground the tank via the green or bare copper wire. Assuming you have a 110-volt system — a breaker panel and hull inlet with circuit protection that was installed to nationallyrecognized codes (NFPA) — connect the white to the common neutral buss and install the breaker into an empty slot in the panel connecting the hot (black) lead to the breaker and the breaker’s other pole to the hot distribution buss. Never directly connect a water heater to a power cord plugged into an outlet on shore. Don’t do any wiring until you have unplugged and stowed your shorepower cord — a wellmeaning soul just might plug it back in again at an awkward moment. Keep all 110-volt A/C wiring physically separate from your DC wiring. Make sure no neutral (white) wires connect to any ground within the boat — this is critical — and make sure your shorepower cord and main AC supply is properly grounded through the dockside power system. Now turn on the pump, fill the tank and turn on the power in that order to avoid heater element meltdown. Check for leaks. There will be a few. (Contrary to popular opinion, AC electrical service does not cause stray current corrosion; this is a DC problem, either within the boat circuit or through the AC grounding wire. If you’re concerned about stray current corrosion, install a galvanic isolator or isolation transformer.) Next, hook up your engine hot-water heat exchanger — consult a mechanic or your local engine representative first. Some raw-water-cooled engines (early Yanmars for example) won’t put out a steady supply of hot water; the temperature alternates between hot and cold as the thermostat opens and closes. Others, such as Atomic 4s, need a separate recirculating pump to help move the engine coolant through the heat exchanger. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 14 PLUMBING 101 / Back page / Next page / Contents page / for heads Add a stock of latex rubber gloves to your tool kit and read on because it’s possible to solve most marine sanitation problems with repairs and upgrades. Fear and Loathing in the Vanity By Nick Bailey In the last issue (1997-#1) we covered all plumbing systems other than the head, otherwise known as the marine toilet or as commonly referred to as a marine sanitation device (MSD). Of all of the onboard plumbing systems, the head has a redundant reputation as a real troublemaker. This notoriety is exaggerated, although not entirely undeserved. MSDs are seldom well-maintained and even less well-understood. Beware, neglect will lead to nasty surprises. If you thought the device was a bit disgusting even when it was working well, then just wait until it screws up! HEADS: The Front End of the Sanitation System There are basically four kinds of marine toilets, classified by how the sewage is moved: manual pump, electric pump, vacuum and gravity. The manual-pump toilet is the most common type. Well-known examples are made by Blake, Groco, PAR (made by Jabsco), Raritan and Wilcox Crittendon. Flush water is pumped in at the same time the sewage is pumped out, usually by a double-acting manual pump. The down stroke of the pump handle forces a piston down, pushing sewage out of the pump chamber through a one-way valve to the holding tank (or overboard to a thru-hull) while at the same time drawing in seawater for flushing from a thru-hull into the upper half of the pump chamber. On the upstroke, the one-way inlet valve is pushed closed and the flush water is forced out along the toilet’s rim. As the piston rises, sewage and used flush water are drawn into the pump chamber ready for the down stroke that again forces everything out the discharge hose. The head inlet valve usually has a small manual control labeled “Flush or Dry Bowl” so that you can control the amount of flush water — a bare minimum if you want to preserve your holding tank capacity, or lots of flush water if you want to purge the discharge hoses before leaving the boat at the end of the weekend. Regardless, the pumping and flushing procedure should end with the valve closed to leave a relatively dry bowl. These traditional heads range widely in price from about $200 to more than $1,000 and vary in complexity. Most have a multitude of seals, gaskets, O-rings and valve surfaces that can foul, stick, clog, jam, wear out and otherwise cause aggravation. Most heads have complete rebuild kits available. The ability to field-strip, clean and rebuild a head is considered an essential life skill for any serious long-distance cruiser. A unique alternative to the conventional manual head is the LaVac head by Blake. This remarkably simple head does away with the complicated pump assembly at the head itself and uses a pump similar to a diaphragm bilge pump but installed on the discharge hose from the head. The most unusual feature is the toilet bowl lid that forms an airtight seal on the bowl itself. When the bowl contents are pumped out, the suction draws seawater for flushing into the head via the usual inlet seacock and hose straight to the rim of the bowl. To pump dry, simply open the lid, which breaks the suction. This head has far fewer moving parts than others, which means less maintenance and trouble. However, large people are advised not to flush while seated on this head! The electric toilet may simply be a powered version of the manual toilet with a hefty DC motor driving a reciprocating crank, which in turn / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 15 RX for HEADS actuates the same basic pump mechanism described above. Alternatively, it may have a macerator pump. The macerator-pump toilet is quite different in that it uses a rubber impeller pump to pull in flush water and, usually driven on the same shaft, a centrifugal or impeller discharge pump with a chopper or macerator blade (not unlike a garbage disposal unit) that purees the sewage so that it won’t choke the pump. These heads have the convenience of push-button flushing, but because the rubber pump impeller will disintegrate if it’s run dry, you don’t have the option of controlling the amount of water used, which can be at least 7.5L (2 gal) per flush. This type of head could prove impractical if connected to a small holding tank system. PAR and Raritan make the most common macerator units. Popular on larger powerboats, the Vacu-Flush head by Sealand (formerly Mansfield) is unique in the marketplace. It uses a vacuum pump — a powerful bellows pump with extra one-way “duck-bill” valves — in line with a vacuum accumulator tank that draws flush water from the potable water system. The vacuum system behaves like a pressure water system in reverse. When the “flush” foot pedal is pushed, a small amount of water is let into the bowl, the discharge valve in the toilet opens and the sewage promptly disappears with a “whoosh” down the discharge hose towards the vacuum tank. Simultaneously, somewhere down in the vessel’s machinery spaces, an automatic pressure switch senses the sudden change in vacuum and engages the vacuum pump. The pump chugs away until it reaches full pressure then the pressure switch shuts it / Back page / Next page / Contents page / down. In the GATE-FREE meantime, it has scavenged the If your boat has gate valves, replace them sewage from the before they seize or break. Many seized gate vacuum side of valves are irrevocably seized to the thru-hull; the system and be prepared to remove and replace the whole delivered it down thru-hull. To do this, sever the thru-hull stem and to the nonfree the valve with a mini-grinder or hacksaw. vacuum holding If the thru-hull nut is also seized, grind off the tank (or wastemushroom head on the outside of the hull, treatment system knocking the remnants through to the inside. Be or overboard). careful not to gouge the hull. This is a nice system. It has the U.S. Coast Guard (USCG) calls relatively low power consumption a Type III MSD. In these areas, it’s and it uses less flush water than any not legal to pump any sewage other. It is, however, costly to install, overboard even if you have a and although more reliable and less treatment system on board. In most finicky than any other electric and U.S. coastal waters (inside the most manual head systems, if things three-mile limit), it’s legal to do go wrong, it can be expensive discharge sewage only after it’s to fix. Vacuum leaks are particularly treated by a USGC-certified Type I sneaky things to track. MSD (i.e. Raritan Lectra/San, The last category of heads is Sealand SanX and others), or Type gravity powered. In these systems II MSD for boats over 9.8m (66’). the sewage drops straight into the These costly units (about US$2,000 storage tank below. The most complete with the head) are small common variety is the portable-style on-board sewage treatment plants (commonly referred to as portathat macerate and disinfect the potties), which stores the waste in a sewage until it meets very specific small, removable tank section of the bacteria counts and standards for head. Some models have deck turbidity (suspended solids) prior to pump out fittings (mandatory in discharge. Canada), some have recirculating flush capability in which the DISPOSAL: The Back sewage in the tank mixed with End of the System deodorizing additives gets pumped around for flushing. Some have a Discharge Hose fairly large capacity and provision for pressure-water flushing. Much has been written by various Unfortunately, some have a bad authorities on head hose. The reputation as cheap, flimsy, prone consensus is that if you install the to leakage, smelly and generally wrong kind of discharge hose it can obnoxious. Many boaters prefer to be a major contributor to head use a bucket (which may or may odor. Head hose should be flexible not be legal in your jurisdiction) and smooth-walled, preferably rather than carry around sewage in heavy-gauge PVC sanitation-grade such a dubious container. hose or top-quality reinforced If your boat operates in waters neoprene. The spiral-ribbed thin designated as “No Discharge wall hose often used is okay for Zones” it must be fitted with what bilge pumps but is too thin for an - Ti p - / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 16 RX for Heads Head Rebuild A rebuild kit includes replacement parts for all the perishable items and a parts list helps you identify other problem areas. 1 Preparation Pump out the holding tank and flush the system well. Shut off any seacocks, disconnect discharge and intake lines, unscrew the mount bolts and remove the head from the boat in order to work on it in less cramped quarters (or remove the pump assembly only). Remove pump assembly from base. Open the head repair kit and carefully check the parts and the enlarged diagram provided. 2 Inlet Valves Remove the valve cover (typically six screws) and remove the flapper valve. Clean all mating surfaces carefully, replace all valve parts with new ones and replace any O-rings and seals on the inlet valve lever. Lightly smear sealing surfaces with silicone sealant. odor-free head hose and the ribs trap sewage. Rigid Schedule 80 PVC pipe or household ABS (DWV service) offer a non-permeable alternative and are useful if you want to eliminate any low spots that tend to hold sewage. Be / Back page / Next page / Contents page / 3 Piston Rings and Shaft Seal Wrap the piston rod and carefully secure with vise grips. Unscrew the pump handle and release the piston to drop or knock out the bottom of the pump housing. Clean and lubricate the pump cylinder. Replace the piston rings or piston assembly, and remove and replace the piston rod seal. With an external seal, unscrew or remove the retaining ring; an internal rod seal must be pried out from the inside. 4 Discharge Valves Remove, clean sealing surfaces and replace the flapper valve at the pump base. Dismantle the discharge elbow, clean out and replace the duck bill or “joker” valve. 5 Seals Replace any sealing gaskets and O-rings, clean all mating surfaces and check carefully for cracks in all housings. 6 Assembly Reassemble care fully. Don’t over-torque the plastic housings, which crack very easily. If cracked, they must be replaced. 7 Clean up Reinstall, hook up, open the seacocks and test for leaks. careful not to use light-gauge Schedule 40 pipe — it can crack, especially when very cold. When shopping for hose, the standard head discharge size is 1-1/2” inside diameter (ID) hose; some macerator-type heads will discharge via a 1” ID. Inlet suction hose is usually 3/4” ID and should be firm and non-collapsible. Vented Loops Regardless of how well or poorly a marine sanitation system goes about its business, there is one thing it must never do and that is sink the boat. This happens more often than you might suspect simply because most heads in sailboats and some in powerboats are installed below the waterline and connected to a seawater inlet. Seawater siphoning into the head bowl results when one of the flapper valves on the head (“Flush or Dry Bowl”) fails. Sailboats spend a lot of time heeled over at angles up to 30° or more, which radically changes what fittings are below the “heeled” waterline. One solution is to always turn off the head inlet seacock when it’s not in use, but this may not be practical if the seacock is inaccessible. Some boats even come equipped with a secondary (accessible) shut-off valve on the intake line. These security measures all depend on the operator to do the right thing, but to err is human. Besides, there are always guests and children and they might not always remember or understand instructions. The proper head installation will incorporate an automatic method of disrupting any siphoning action. To accomplish this, configure the inlet hose with a tall loop above the waterline and close to the underside of the deck between the head pump and the bowl. This may require the removal and replacement of the standard hose fitted on the toilet. At the top of the loop, install a special Ushaped fitting known as a vented loop or anti-siphon vent. The vented loop incorporates a small one-way / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 17 RX for HEADS Thru-hulls The head inlet and discharge thruhulls should have reliable, quickacting valves. Seacocks with integral quarter-turn valves or thruhulls combined with a ball valve of stainless steel, bronze or Marelon are much preferred over gate valves. polyethylene, available in shapes to fit most locations. If made of linear (not crosslinked) heavy-gauge 6mm to 9mm (1/4” to 3/8”) seamless polyethylene, they will give excellent service. Lighter gauge tanks are flimsy and prone to odor penetration. Heavy-gauge (2mm (3/32”) or thicker) stainless-steel tanks are strongest and the least odor permeable. However, in the long-term (five-plus years) such tanks corrode from sewage acids. Corrosion attacks the seams first, leading to leakage and the need to remove and repair them. (Aluminum and other metals are unsuitable holding tank materials because they are less corrosion-resistant than stainless steel.) Bladders or flexible-rubber tanks are sometimes used. They are difficult to secure and, as a result, they are subject to chafe, particularly in a sailboat. Flexible tanks are also tough on the fittings connected to them. These tanks must be inspected requently, so should be installed in an easy-toaccess spot. Also, some head chemicals may “devour” the rubber, creating a repulsive smell more intense than any known head odor. Remember, sewage weighs 3.6kg per 3.8L (8lb per gal), which is a lot of mass sloshing about. When choosing a tank it makes sense to spend the extra money for a good one. Add a Holding Tank If you need to fit a tank, decide first what size you need. Do you use the boat for day trips, weekends, or extended cruises? The minimum average flush volume per person per day is about 11.3L (3 gal). Therefore, a couple on a weekend cruise will need a tank capacity of 45L (12 gal). For two couples, 91L (24 gal) is the minimum. The other consideration is how big a tank you can fit into the boat. Stock polyethylene tanks are available in many shapes and sizes and custom stainless-steel tanks can be built to suit your available space. (Refer to Figures 1, 2 and 3 for typical holding tank installations.) It’s also possible to build a DECK PUMPOUT FITTING Holding Tanks Many boating areas in North America, in particular most freshwater lakes and rivers, don’t allow marine sanitation systems to discharge any sewage overboard whether it’s treated or not. The boat must be without an installed toilet on board or the head must have a holding tank. Holding tanks come in all types. On boats built for saltwater markets, the holding tank may be an afterthought, either too small, inaccessible for maintenance or generally substandard. The most common tanks are molded VENT LINE HOLDING TANK INTAKE THROUGH HULL DIP TUBE P-TRAP Figure 1 “No discharge” deck pumpout only. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 AMERICAN BOAT & YACHT COUNCIL air valve that opens if any suction is present in the hose, allowing air to enter the line and break the siphoning action. A similar siphon break is required on the discharge hose if it’s connected to a thru-hull. There are a few problems with vented loops. The anti-siphon vent fitting can clog with debris, calcium or salt crystals and quit working. To prevent this, clean periodically. As well, sewage odors in the discharge line vent sometimes filter into the boat. To eliminate this, attach a small diameter hose to the nipple on top of the vented loop and lead it to an overboard vent fitting mounted well above the waterline or connect it to an existing holding tank vent. Alternatively, feed the hose into a cockpit scupper provided that it’s above the waterline at all times. / Back page / Next page / Contents page / 18 RX for HEADS / Back page / Next page / Contents page / DECK PUMPOUT FITTING VENT LINE SIPHON BREAK "Y" VALVE AMERICAN BOAT & YACHT COUNCIL AMERICAN BOAT & YACHT COUNCIL VENT LINE HOLDING TANK INTAKE THROUGH HULL OVERBOARD DISCHARGE PUMP DISCHARGE THROUGH-HULL Figure 2 Overboard discharge option after the holding tank. fiberglass or wood-epoxy tank or glass in an existing seat locker and convert it into a tank. In order to resist stress cracking and avoid pinhole leaks, it should be heavily built and thoroughly epoxy-barrier coated on the inside to prevent moisture penetration. (See page 27 for instructions on building a wood-epoxy tank.) Any installed tank must be strong enough to carry the full sewage load and it must be securely blocked or clamped in place. Any movement or flex puts stress on the inlet, discharge and vent connections and either cracks the tank at the fitting or the fitting itself cracks. When space is tight, convert your water tank to a sewage holding tank and then squeeze a bladder tank into some nook and use it for water. At least if the bladder tank leaks you won’t be subjected to a horrifying stench. If your existing water tank is polyethylene with the usual 1-1/2” fill fitting and 1/2” vent and outlets, you will have some difficulty replacing the 1/2” outlet with a 11/2” pumpout discharge fitting. If the tank is heavily reinforced, the water outlet can be enlarged with a holesaw to accept a 1- 1/2” hose barb mushroom-style thru-hull (preferably reinforced plastic) with backing nut. Caulk the thru-hull well with a polyurethane sealant (3M 5200, Sikaflex or other). This modification has been done successfully but because polyethylene does not bond well to most sealants, the seal may fail. I recommend replacing the tank with another the same size but equipped with the correct fittings. All hose connections should be double-clamped with stainless-steel clamps, and any head installations below the waterline should have vented loops on the intake and discharge lines. To prevent noxious odors emitting from a vented loop, attach a hose from the valve to an overboard vent mounted above the waterline (Figure 4) or tie it into DECK PUMPOUT FITTING HEELED WATERLINE VENT LINE SIPHONE BREAK WATERLINE AMERICAN BOAT & YACHT COUNCIL INTAKE THROUGH-HULL HOLDING TANK TYPE 1 "Y" VALVE DISCHARGE THROUGH-HULL Figure 3 Overboard discharge option before the holding tank. Figure 4 To prevent water from siphoning back into the head, install a vented loop in the inlet hose (and the discharge hose if connected to a thru-hull) located above the maximum-heeled waterline. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 19 RX for HEADS the holding tank vent or cockpit scupper. It’s also worthwhile installing the largest practical vent diameter or two vents on the tank to assist with the oxygenation of the sewage (see “Odor Control” below). Note: On boats with optional overboard discharge, the Y-valve must be secured with a padlock, cable tie or the valve handle removed when operating within the three-mile limit. Odor Control There are several sources of head odor of which leaks are the worst cause — find them and fix them. Discharge hoses, even top-quality ones, eventually become saturated and odor penetrates the walls. To check your head hose for odor permeability, try the rag test. Wipe the outer surface of the hose with a damp cloth. If the cloth smells, the hose is permeable. Replace immediately. To eliminate hose odor, avoid sewage remaining in the line for long periods. Flush well or even revise your hose routing to minimize low spots or traps. Consider replacing hoses with straight-through plastic pipe but keep in mind that the proper size head-to-pipe or hose-to-pipe adapters may be hard to find. The inlet hose can be another cause of odor, particularly in saltwater. Marine growth decomposing in the stagnant water of an intake line can mean the first flush of the weekend will reek. A strainer on the inlet line can help solve this. Periodic purging of the entire inlet line with a 30% solution of vinegar and fresh water will also help. Never use bleach or other commercial cleaners in a marine toilet; it can attack the rubber and metal parts. Low-cost in-line head chemical dispensers, such as the Head-O- / Back page / Next page / Contents page / Figure 5 The Head-O-Matic Tank-ette installs in the intake line and auto-feeds head chemicals to treat water pumped to the head. Matic Tank-ette (Figure 5), treat all water pumped to the head to eliminate intake odor. Easy to install, the Tank-ette (CDN$59.95/ US$39.95) clamps onto a 3/4” intake line (use adapters for other hose sizes) mounted above the waterline. A bullet of blue solid chemical drops into the unit and is replaced after one month or when the water runs clear. Replacement bullets cost $9 or less. An optional E-Z Flush cap facilitates winterizing or flushing of the head. The discharge joker valve can leak allowing sewage to back up into the head. Or if the piston rings are worn, sewage can leak past into the flush-water side, contaminating it. Then it’s time for head repairs. Another source of odor is generally head area cleanliness and, although unpopular (and probably unenforceable), a “guys sit to pee” rule will reduce splash, odor and cleaning. Cheap, lightweight, polyethylene tanks are odor permeable; heavy-gauge tanks are much less so but odors may eventually seep through. Septic-tank sewage odor is a by-product of the anaerobic bacteria that thrive in the oxygen-deprived, carbon-dioxide- rich environment of most holding tanks. This is why municipal sewage treatment plants aerate sewage to promote the growth of aerobic oxygen-loving bacteria, which give off much less odor as they naturally break down the sewage. The same is true of backyard composters. Peggie Hall of Peal Products, a company specializing in marine sanitation systems in Atlanta, Georgia, advocates a simple, innovative approach to naturally eliminate sewage smells in the tank. The key is to fit the largest practical cross-flow vent system to the tank — usually two independent vent lines of 2.54m (1”) diameter hose to each side of the boat (Figure 6). This sets up true cross-flow ventilation of the tank, clears out the carbon dioxide and prevents oxygen starvation, which allows the aerobic bacteria to gain the upper hand over the smelly anaerobic types while breaking down the sewage by natural fermentation. Although it might seem counterintuitive, this enlarged vent system is reported to eliminate most holding tank odors. For the idea to work, the vent hoses must be as short as possible and free of low spots that can trap air. It’s also important that the hoses aren’t restricted by filters or tiny screened fittings on the outboard end. With sailboat installations, care must be taken that the vents come straight up from the tank top to avoid filling while the boat is heeled. They should exit at locations above the waterline at all times (i.e. the bow or the transom). According to Hall, the rule is: The less fresh air a holding tank gets, the more it will stink. Vent maintenance is also important in odor control. Vent lines are easily blocked by spider webs or by sewage if the tank has been / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 20 RX for HEADS More Routine Maintenance Maintenance Rule #1 is to make sure that everyone who uses the head understands that it’s not connected to the town drain and that it is by nature a finicky, cantankerous, spiteful device. All instructions must be strictly obeyed, such as “Don’t put anything in the - Ti p - DRIP PAN A plastic pan or cutoff jug bottom placed underneath the lowest point in the system will prevent any unpleasant extract from spilling into the bilge when you drain it for maintenance. head unless you have eaten it first.” It’s claimed that the legendary Wilcox Crittenden Skipper head can flush an overcoat, but for the rest the only exception to the “eat first” rule is marine or ultra-cheap one-ply toilet paper. If Rule #1 is followed, heads don’t need much maintenance. Check that the vents are clear — be aware of any sudden resistance in Anne-Marie Hendry overfilled and “ram fed” by the head pump — especially if the outside hull vent fitting is tiny and screened. This can lead to a dangerous situation since the fermenting sewage produces gases and pressure builds. It doesn’t help if your guests stand on the pump handle to pump the head due to the back pressure. I have seen heavygauge rectangular polyethylene tanks blow up like balloons and break the joinery meant to contain them. There’s also the urban legend of the couple in fancy dress whites taking their friends by boat to the Commodore’s Ball. They realize they need a last minute pump out, blissfully unaware that a 6m (20’) geyser of raw sewage would erupt when the deck fitting was opened. The opposite happens when the vent is clogged during a pump out. The large diaphragm pumps will easily suck a heavy stainlesssteel tank flat into a crumpled pancake. So check the vents periodically for blockages and spider webs. A ruptured holding tank is the smelliest one of all. / Back page / Next page / Contents page / Figure 6 Eliminate most holding tank odors caused by oxygen-starved bacteria by fitting the largest practical cross-flow vent system to the tank. pumping effort and never force the pump. Experts recommend occasionally flushing half a toilet bowl of warm water with biodegradable laundry detergent through the system followed by two ounces of mineral or baby oil (not vegetable oil, which slimes up the lines and tank). Periodic greasing of the piston rod is also recommended. The oil will help the head and the detergent will emulsify the oil in the tank to preserve good bacteria. If the boat is equipped with a Type I or Type II MSD, do not flush cleaner or treatment into the system unless it was specifically designed and sold for that purpose. Many pros recommend a complete head rebuild every two years as the best preventative maintenance program. (Add this task to your spring recommissioning list.) This ensures the head is always in top shape and it also guarantees that you will be familiar with the - Ti p - HEAD FILL-IN What do you do when the head is not working? Carry a supply of FlushMe-Nots. Line the head bowl (or a bucket or whatever else fits) with the plastic bag then add some high-tech powdered absorbent (it’s part of the package). After use, seal the bag with a twist-tie and dispose of it as you would a diaper. (Contact: F.C.P. Products, Box 229, Billerica, MA 01821; Tel: (508) 783-2500.) unit when repairs are needed. In saltwater, calcium can build up in the toilet and lines and almost becomes like a hard coral growth due possibly to microscopic diatoms. Periodic flushing with vinegar will help dissolve these deposits, but if they are severe and the head becomes difficult to pump, you may have to replace the hoses or carefully flush the system at least once with diluted hydrochloric acid (muriatic acid). This must be done carefully as the acid can slowly attack metal parts in the head system. Regularly check all hose connections for new signs of leakage. To check the operation of the anti-siphon valve, blow through a piece of hose fitted over the nipple. Simple maintenance habits also help to minimize odor; the last flush of the cruise, especially at the end of the weekend, should always be a thorough one to eliminate sewage standing in the discharge line. Nick Bailey has been in the marine service profession for more than 20 years and currently is service manager of Bristol Marine in Mississauga, Ont. He and his wife own and race a wooden Thunderbird on Lake Ontario. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 21 RX for HEADS Pump works freely but head won’t draw in flushwater / Back page / Next page / Contents page / Check intake seacock is open CLOSED Head leaks Carefully tighten Pump works freely but bowl fills faster than it drains OPEN Open and try again Pump harder Check level in holding tank NO Temporary sticking one-way discharge valve NOT FULL Pump piston rings not sealing or piston broken NO Check overboard discharge seacock for calcium build-up Pump doesn’t work freely OKAY REBUILD HEAD Still leaks OKAY FULL Remove hose and check for blockage or loss of prime Check and clear vent Discharge valve may be clogged NO YES Treat with acid Check inlet valve is open YES Pumpout tank and check vents are clear Bowl fills back up when unattended Inlet or discharge valve leaking Pump and close seacocks one at a time If sewage, clear or replace discharge valve / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 22 TANKS MADE-TO-MEASURE TANKS for 12 years without any bad tastes or odors. The tanks were constructed with West System brand epoxy, but I’m sure other resins would net similar results. Carefully measure the space for the tank, then make a cardboard template. Assemble the pieces using masking tape to hold it all together. Dry-fit the Figure 1 template, then trace the patterns A tank constructed of plywood and onto the plywood. Building a “waterproofed” with rectangular tank is multiple coats of epoxy resin. Baffles straightforward: cut the ends, prevent the contents from surging in sides, bottom, top and baffles out the tank and scallop-shaped cutouts in the corners vent each compartment. of 1/4” marine-grade plywood for tanks up to 151L (40 gal); use When you need extra tankage 8mm or 9mm (5/16” or 3/8”) ply consider making your own. for larger tanks. Because the Potable water and holding tanks bottom and top overlap the sides made of plywood coated with and ends, you’ll need to deduct epoxy resin are inexpensive, double the thickness of the simple to build and are easily plywood from your height custom-made to fit any tank shape measurements. Decrease the width or hull contour. Epoxy is the ideal of the sides by the same amount to tank material. It waterproofs the allow for the overlap of the ends. plywood yet won’t contaminate To build a tank that conforms to the drinking water and is resistant to contour of the hull, head chemicals. I’ve used laminate multiple wood-epoxy water tanks sheets of thin on Nutcracker veneer to the required thickness over a wood form (mold), then join as described below. Tanks larger than Figure 2 19L (5 gal) should have To form a fillet, apply a bead of thickened epoxy (use a syringe internal or a heavy-duty plastic bag with a small hole cut in one corner), then pass a tongue depressor held at a 45° angle over the baffles to mixture to remove excess and form a smooth fillet. Use a putty prevent the knife to scrape the excess epoxy on either side of the fillet for a liquid from smooth concave edge (A). dry en eH ari -M ne An Anne-Marie Hendry / Back page / Next page / Contents page / surging inside the tank. The number of baffles depends on the size of the tank. A 151L (40 gal) water tank, for example, requires two or three baffles spaced 30cm (12”) or less apart to ensure sufficient support. Cut deep scallops in the lower and upper corners of each baffle (see Figure 1) so the contents flow freely between compartments. Assemble the tank in two sections: the main tank with the baffles, then the top. Both are assembled separately and completely finished, then the top is glued in place. Join the sides, ends and bottom panels using cleats (2.5cm/1”) triangular pieces of wood) attached with thickened resin. Use staples, small copper nails or pipe clamps to hold the panels in place until the glue sets. Alternatively, bond the panels together using fillets: epoxy thickened with colloidal silica to a peanut-butter consistency that, when applied to an inside corner, forms a cove-shape bead over the join (Figure 2). For added strength on larger tanks, cover the fillet with fiberglass tape and resin. The goal is to have rounded, smooth corners. With either method, apply thickened epoxy to all plywood mating surfaces. Scrape or sand off any excess epoxy, then sand the wood (and fillets) with 120-grit paper. Coat the interior of the box and the underside of the top with a minimum of four coats of unthickened resin. Apply three coats “green on green” — recoat when the resin is just slightly tacky and before it reaches its final cure stage (about 2-1/2 to 3 hours at room temperature). After the third coat let it cure thoroughly, then sand to a glass-smooth finish with 120-grit paper. This ensures an / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 23 TANKS / Back page / Next page / Contents page / A removable wood-epoxy water tank fits snugly in the vee-berth and has two inspection ports for cleaning. A stainless-steel cable with adjustable turnbuckle attaches to the bulkhead and leads around the tank to a floor-mounted pad eye to hold the tank securely in place. A rubber gasket under the wire on the forward edge protects the tank from chafe. easy-to-clean surface. Because epoxy is transparent, add a white pigment (paste or powder) to the last coat at the rate of 5% by weight so you can easily see the scum when cleaning the tank. Cut holes in the top for large clean-out ports: install 10cm or 15cm (4” or 6”) screw-in plastic inspection ports, positioned so they provide access to the entire tank for cleaning. On tanks with multiple baffles, locate the ports between each baffled section. Mark the placement for the vent, fill and discharge hose fittings, then glue backing blocks made of 12mm (1/2”) stock to the top exterior where marked. When cured, drill the holes. A typical potable water tank has a 16mm (5/8”) vent, 3cm (1-1/2”) fill and 12mm (1/2”) outlet; a holding tank has one or two 16mm (5/8”) vents and 3cm (1-1/2”) inlet and pumpout. Glue the top to the tank, and hold in place with staples or clamps until set. Apply three coats of resin to the exterior of the tank, followed by two coats of an enamel or polyurethane paint. Install the hose fittings with sealant, then securely mount the tank in the boat. A word of caution: wood-epoxy tanks are not recommended for fuel storage due to the risk of fire. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 24 PLUMBING 101 / Back page / Next page / Contents page / installing a PRESSURE-WATER SYSTEM Tools & Materials Drill & bits Assorted screw drivers Sharp utility knife You need not buy a new, expensive boat to enjoy some comforts of home. Follow these easy instructions for installing a pressurewater system then just turn a tap and water flows. What could be better! FLOJET model 2840 Water Pressure System Hose: 19m (3/4") inlet, FLOJET model 2840 Water Pressure System mounted on an engine room bulkhead. Note strainer in foreground. 12mm(1/2") outlet All-stainless hose clamps W hen we bought our boat in 1978, it was remarkably well equipped for its day. It boasted an electric water heater, a pressure water system, an enginedriven generator (in addition to the ordinary alternator) and two electric heads. Since our philosophy at the time was a keep-it-simple minimalism, out came all of the above. I don't recall the fate of the water heater or pump, but one head remained on the dock in Nassau (with permission from the dock owner), the other became a planter in a Florida boatyard and the generator found new practical use in its recycled life as the basis for a mooring in a Bahamas harbor. Now, 20 years later and settling into a different kind of liveaboard lifestyle, the simple life has less appeal. The idea of the easy life is taking on new significance and so, after years of a hand pump in the galley and a foot pump in the head, our classic boat is now equipped with a very modern pressure-water system. Initially, plumbing might seem to be one of those jobs requiring a knowledgeable outside person, but as more manufacturers have become attuned to the "I'd-rather-do-it-myself" thinking, the installation of such a system fits in the category of the average boat owner's capability. All boat projects should be planned carefully, to avoid do-overs and to make sure everything you'll need is on board. With this project, the planning stage will establish the shortest routes for hoses to follow and the most centrally located place for the pump, assuming it may be / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 25 WATER SYSTEM TROUBLESHOOTING: REDUCE PLUMBING SYSTEM NOISE By Chris Beh Positive displacement pump "noise" can be attributed to many factors. The way the pump operates lends itself to some noise, inherent in these devices, but you can reduce the amount of noise transmitted to the boat by carefully following a few installation details. Be sure to mount the pump on a solid surface with solid supports underneath. If you can knock on the serving more than one faucet. The system we installed is a FLOJET (US$294.55) — an all-inone pump (Quad diaphragm unit) and accumulator tank with a built-in pressure switch and a separate inlet strainer. Compact and lightweight, it fits in a locker and weighs just 4kg (8.8lb). Once installed, the pump pulls water from the boat's water tank and sends it to the accumulator tank. With the accumulator tank, the pump doesn't run constantly whenever a faucet is turned on. The tank retains enough pressure to allow the water to flow for a short time without the pump working. When pressure in the accumulator tank drops to a certain level, the pump turns on to refill the water and restore the pressure in the tank. FLOJET's system also includes a strainer installed between the water tank and the pump. This prevents any sediment that may be in the water tank from reaching the pump and fouling the valves. Location, Location Of course, the closer the pump can be to the faucet(s) and the shorter / Back page / Next page / Contents page / mounting surface and it sounds like a drum, vibrations are going to travel through it. Use the manufacturer's supplied rubber feet to mount the pump and don't overtighten. To reduce vibration, use at least 45.7cm (18") of high-pressure flexible tubing between the pump and "hard" plumbing both on the inlet and outlet fittings. Elbow fittings cause turbulent flow and back pressure on the pump, increasing noise levels, particularly if placed within the first 61cm (24") of the pump outlet. Better to replace elbows with high-pressure flexible tubing. Another source of plumbing noise the hoses, the simpler your plumbing maze will be. Our boat had a good start: the center cockpit is immediately aft of both the galley and the head. The pump could fit neatly in one of two huge seat lockers or be mounted in the engineroom beneath. The engine room allowed easiest access and a bulkhead was vacant. The FLOJET unit can be either deck-mounted or bulkhead-mounted to a solid surface. If bulkhead mounted, the pump head should be down or lower than the motor. Once installed, the strainer would be visible and easy to clean. Installation Gathering tools for this job is especially easy: all that's needed are a drill and bits, screwdriver and a sharp knife to cut hoses. First, assemble all the parts. Besides the unit itself, have handy all needed hose lengths, a good supply of all-stainless hose clamps and whatever adapters you may need to connect faucet to hoses. Be sure to use reinforced hose made for highpressure applications. And, of course, you'll need the faucets(s). is vibration from piping and fittings where they pass through bulkheads and behind drawers and shower walls. To check for noise, grab the piping on either side of the pump. Does the noise and vibration level decrease while you hold the piping? Turn on the tap(s) one at a time and check which one(s) creates excessive noise or vibration. Check the strainers. Clogged strainers, as well as air leaks, can make a pump labor and cause noise. About the author: Chris Beh is an applications engineer for SHURflo in Santa Ana, Calif. The standard household kitchen faucet might be too big for a boat sink as it arches up too high. Bar sink or laundry tub faucets are better, having a lower arch or none at all (faucet extends almost straight out over sink). Before mounting the accumulator in position, attach hoses to the pump: the inlet hose connects to the water tank and the outlet hose goes to a faucet(s). Screw the pump unit into its chosen place with the supplied four rubber mounting feet, then run the hoses. Eventually, you'll include all the required tee-fittings that will lead cold water to each faucet (galley, head sink and shower) plus one hose into the water heater and another out of the heater and directed to each hot-water faucet (Figure 1). But start with one faucet; ours was the galley sink. Securely fasten the strainer to a bulkhead, cut the water supply line from the tank and connect the ends onto the strainer. Clamp all hose connections securely. Wiring As with any wiring project, remember to disconnect the power / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 26 WATER SYSTEM 1 / Back page / Next page / Contents page / Shower Head Water Heater Galley Faucet Head Faucet Hot Water Cold Water Water Tank Water Tank Strainer FLOJET (Mounted on Bulkhead) Cross-section view shows components installed in a pressure-water system. before you start. This is a very basic job: take the negative (black) and positive (red) wires coming off the pump and connect them to the appropriate distribution panel. Splice an in-line fuse into the positive wire. Check pump specs for the recommended fuse size. FLOJET models are available for 12, 24- and 32-volt DC systems, and 115-volt AC that plugs directly into an AC outlet. The tank should be pressurized before starting the pump. Use a bicycle tire pump to pump up the pressure. Follow manufacturer's instructions and check the pressure after filling and before starting the pump with a pressure gauge. Like a bike tire, pressure can be reduced by pressing the center pin of the valve. Start Up See that the water tank is at least 1/4 full. Open the faucet(s) to purge air from the system. Turn the power on so the pump will start. When air is out of the system, about a minute or so, close the tap(s). The pump will pressurize the tank, and then turn off and on automatically as required to maintain the pressure in the system. You could add another element to the system: a water filter, for good drinking water. If you're dockside on a relatively permanent basis, you can connect directly to city water supply, but if you choose to do so, install a regulator to protect the pump from the high water pressures (see "Now That You Have Pressure Water..." on page 36). Next on our do-to list is to install a water heater, shower and sump. [For step-by-step instructions to install a water heater see DIY 1997#1 issue, page 20 — Ed.] About the authors: David and Zora Aiken are the authors of Good Boatkeeping and Good Cruising published by International Marine. The Aikens currently live aboard a 1963 10.5m (35') Chris-Craft sloop, Atelier, berthed in Grasonville, Maryland. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 27 PLUMBING 101 / Back page / Next page / Contents page / KEEPING DRY BELOW DECKS Is your boat’s existing bilge pump system adequate? Here’s the lowdown on pump types, flow rates, installation options and other information you need to evaluate and plan an upgrade. By Nick Bailey D espite the fact that most boats are fitted with one or more bilge pumps, sinkings are common nonetheless. I’m always amazed how many boats are only a corroded fuse or dead battery away from sinking. Even more amazing is the blind faith boat owners have in what is often a very fragile and inadequate pump system. Many pumps are hard pressed to keep a boat afloat at the dock, let alone in the event of an emergency underway. A properly installed and maintained bilge pump system is your second line of defense against sinking, behind a watertight hull, and so deserves your earnest attention and resources. Types of Pumps Most bilge pumps are either centrifugal (submersible) or positive displacement (non-submersible) type. Both types can run dry for sustained periods without damage, unlike a flexible impeller pump which overheats and comes apart almost immediately if run dry. Centrifugal pumps (common submersible pump) have a curved solid impeller designed to sling water entering from the center axis of the pump housing into an outlet pipe mounted tangential to the housing. A centrifugal pump moves water by momentum alone and as no suction is created it won’t self prime. Many have a detachable base plate, fastened by screws in the bilge and the pump motor assembly snaps or twist locks into the base plate. Slots incorporated in the motor or base plate housing serve as a debris screen to keep the impeller from fouling. A discharge hose leads to a thru-hull above the waterline. It’s a very simple plumbing installation in concept but one that is subject to a variety of problems — connecting a discharge hose often cuts actual pump performance down to half (or less) of rated capacity (see “Pump Performance”). Positive displacement pumps use a reciprocating flexible diaphragm or piston to force water out of the pump on the down stroke and suck water into the pump on the upstroke. The pump inlet and outlet have a one way flapper or duckbill valve to ensure that fluid can only go in the desired direction on each stroke. Due to the suction created, pumps are self priming and often mounted remote from the bilge with only intake hose and bilge strainer, a useful feature for boats with a bilge sump too narrow or inaccessible to fit a submersible pump, or in shallow bilges where bilge water level must be kept to a minimum. The weakness of diaphragm pumps is their limited capacity. Even electric diaphragm pumps don’t get much above 1,200 gallons per hour (gph), a capacity otherwise expressed as 20 gallons per minute (gpm). This is due to the inefficiency of their one-gush-ata-time reciprocating action. Most manually actuated bilge pumps are the diaphragm type (i.e. Edson, Bosworth, Henderson, Whale) with rated capacities from 5 to 30 gpm. As all diaphragm pumps are easily crippled by debris lodging in oneway valves, a bilge pick-up strainer or in-line filter must always be installed. Pump Performance For all pumps, manufacturers provide the rated capacity and flow rate data. Nominal ratings are based on “open flow” conditions; for example, the pump is operating in a bucket with no hose attached. This nominal “maximum flow” rating does not even remotely indicate how a pump will perform in a typical installation. The hydraulic head pressure the pump must overcome to push water through the hose and up to the discharge thru-hull governs realistic pump performance. Two factors contribute to head pressure: static head — vertical distance from the pump to the discharge thru-hull — and dynamic head, which is the total frictional resistance within the discharge plumbing, usually expressed as an equivalent to feet of static head. Adding static head to the dynamic head gives the total head pressure (also expressed in feet) that the pump must overcome. Pump manufacturers usually provide / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 28 KEEPING DRY / Back page / Next page / Contents page / How Big a Bilge Pump? There are no mandatory pump size requirements for pleasure craft from Figure 1 15 SAMPLE SUBMERSIBLE PUMP PERFORMANCE 3/4" outlet 1" 10 1.5" outlet 5 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 FLOWRATE (gpm) the U.S. Coast Guard or even any recommendations from the American Boat and Yacht Council (ABYC). The American Bureau of Shipping (ABS) recommends that vessels under 19.5m (65') be equipped with a 24 gpm and a 12 gpm pump totaling 36 gpm (or 2,160 gph). If we assume this recommendation is for actual pump performance, then this spec calls for a pumping capacity of 5,000 gph or larger, depending on how restrictive the installation. Without detailed small craft recommendations your pump choice largely depends on whether you view it as a convenience to dewater the bilge from minor leaks or as a major safety system designed to keep the boat afloat in the event of a critical failure such as a broken thruhull or ruptured shaft log. According to a graph (Figure 2) adapted from Figure 2 - FLOODING RATES (gpm) Depth of Hole outlet WHALE HEAD (feet) information regarding the maximum allowable head height and a graph of flow versus head height (Figure 1). Another important capacity factor is whether full voltage is available to power the pump. Open flow rating is usually based on pump performance with a 13.6-volt DC power supply. (This represents the voltage available while the engine is running and alternator is charging.) In actual usage, this voltage is rarely available at the pump. The engine may not be running, wiring may be too small in gauge for the length of run, there may be corroded connections or the batteries may not be fully charged. All these conspire to reduce available voltage and the pump’s actual performance. It’s possible to theoretically calculate what flow rate can be expected in a given installation, but as a rule of thumb assume a 50% reduction in flow rate for a normal installation, and even worse for an installation with high head pressure. Since submersible bilge pumps won’t lift water beyond a 1.8m to 3m (6' to 10') head, it’s important to check the pump’s performance specifications in relation to the requirements of your particular installation. Diameter of Hull Opening the “Navy Salvor’s Handbook” by Nigel Calder and published in Professional Boat Builder No. 57, a 25mm (1") hole 30cm (1') below waterline lets in 1,200 gph, a flow rate which looks manageable. A 50mm (2") hole at the same depth floods at the rate of 79 gpm or 4,760 gph, a situation equivalent to the failure of a large thru-hull and a flow rate that exceeds the rated capacity of any bilge pump. The largest popular submersible pumps on the market range from 4,000 to 8,000 rated gph and require 5cm or 7.6cm (2" or 3") discharge hoses. Assuming the typical 50% of rated performance, even the 8,000-gph unit won’t keep up with a 5cm (2") hole. Nonetheless, if a system is to be considered adequate for anything other than routine dewatering, it should be able to cope with the most likely failure, if not the very worst case emergency. 1" 1.5" 2" 2.5" 3" 3.5" 4” 6” 1' 20 44 79 123 177 241 314 707 2' 28 62 111 174 250 340 444 1,000 3' 34 77 136 213 306 417 544 1,124 4' 39 88 157 245 353 481 628 1,414 5' 44 99 176 274 395 538 702 1,581 6' 48 108 192 301 433 589 770 1,731 System Planning Before upgrading an existing pump system, it’s necessary to evaluate your boat’s layout. The first question is whether the boat is divided into / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 29 KEEPING DRY - Ti p - / Back page / Next page / Contents page / WATERPROOF WARE When you have a very wet boat and need to keep connections dry and corrosion free, use a watertight plastic container and terminal strip. A similar concept to the watertight fuse box described in “DIY Projects,” 1999-#1 issue, put the terminal strip loose in the box, pull wires through a single hole punched in the bottom, attach ring connectors to wires and connect them to the terminal strip, mount the box to any convenient nearby vertical surface and snap on the lid. Make sure the hole in the box faces down so rising or dripping water can’t get in. — Jan Mundy separate compartments that, if not watertight, can at least retain water up to a damaging level. Each separate compartment should have its own bilge pump sized to handle the likely source of leak in that compartment (see “Pump by the Numbers” on page 16). A 7.5m (25') cabin cruiser, for example, typically has the engine compartment separated from the cabin by a watertight bulkhead. In the cabin, there may be a 12mm (1/2") head intake and two 25mm (1") sink drains. A single 2,500 gph should be adequate to handle one broken thru-hull assuming two won’t break simultaneously. In the engine compartment the most common worst case scenario is a ruptured water intake or exhaust hose also equivalent to a 25mm (1") flow rate of 1,200 gph, so a second 2,500 gph unit should suffice, provided the exhaust outlet stays above water. A smaller open or cuddy cabin 23-footer is at risk of being swamped in a big sea, or even in a heavy rain. Although cockpits are self draining, a lot of water still gets in through engine hatch covers and need the largest possible pumps to handle the flow. If your boat doesn’t have separate compartments or large limber holes draining into a common bilge, two pumps on separate circuits should still be considered the minimum to provide back up in case a pump fails or clogs. At least one of the pumps should be of high capacity to deal with a worst case leak. Sailboats often have a very narrow or shallow bilge that cannot accommodate a larger submersible pump. A small submersible electric pump or typical standard-equipped manual diaphragm bilge pump, although fine for routine dewatering, is not adequate for emergency use. Any boat that is configured in a way that prevents the installation of a properly sized electric pump is a good candidate for a standby emergency-only bilge pump system (see below). Larger boats have more equipment, more and larger thruhulls that tend to be situated deeper in the water. This increased depth increases hydraulic head pressure behind a leak and resulting rate of flooding. Emergency-Only Pumps For small boats, an Edson selfcontained, portable pump kit fits in a cockpit locker and is quick-toassemble when needed. A viable strategy for an effective emergencyonly pump for larger boats would be a standby high-capacity, enginedriven pump (pricey) or a large submersible electric pump (more affordable upgrade) mounted in the lowest available space in, or near, the bilge. Rubber-impeller style engine- Figure 3 B A Alarm (opt.) On/Off/ Auto Switch C Manual pump BIlge strainer DAVID AIKEN Pump Clutch pump unit Pump switch TYPICAL PUMP INSTALLATIONS A: Manual diaphragm pump (i.e. Edson) with inline strainer keeps debris from clogging the pump. B: Submersible bilge pump with separate float switch, on-off-manual switch and optional red light (and/or audible alarm) operation indicator. C: High-capacity engine-driven clutch pump has manual on-off lever (or electric) and includes bilge strainer. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 30 KEEPING DRY driven pumps from Jabsco are capable of self priming and are engaged by either a level-actuated manual clutch or by a remote switch actuated electric clutch (Figure 3, C). The largest version has a rating of 5,000 gph at full speed (2,200 rpm) and a conservative capacity rating at 3m (10') of head. Intended for higher horsepower engines (30 plus), engine-driven units obviously require you to become aware of the leak before the engine drowns, so some kind of high-water alarm would be useful (i.e. Bilge Sentry, Ultra Pumpswitch Senior). Like any impeller pump, if the engine-driven pump runs dry it will quickly smoke the rubber impeller, but by then you have presumably stopped the leak. If you want to get fancy on electric clutch versions, install a vacuumsensing switch that detects when the pump sucks air and disengages the clutch. / Back page / Next page / Contents page / Figure 4 PRIMARY AND BACKUP PUMP INSTALLATIONS 3-way Switch A Primary pump and switch B Alarm (optional) Secondary pump and switch 3-way Switch Primary pump and switch Installation Guidelines Manual bilge pumps (i.e. Edson) are robust, simple devices and seldom fail. Electric bilge pumps are also robust and simple but reliability is another matter entirely. When an electric bilge pump fails, it’s rarely the fault of the pump but more likely to be a result of poor installation or maintenance: faulty wiring, a clogged pump inlet, and a stuck or broken float switch. (See page 22 for complete installation details). Positioning: A submersible pump must be firmly fastened in the deepest part of the bilge. If access to the ideal spot is difficult, or you are reluctant to drive screws into the hull, mount the pump on an aluminum Lshaped bracket and fasten this to anything convenient and solid, like a stringer or rib. If you are planning to mount two pumps, it makes sense to have one larger than the other and mounted higher up (Figure 4). The Secondary pump and switch A: Both pumps on same circuit; B: Backup pump on separate circuit. smaller pump (lower power consumption) would be your every day pump and the larger reserve, back-up pump used when the other fails, or the rate of flooding exceeds the smaller unit’s capacity. With planing powerboats, the lowest point while underway may be different from the lowest point at rest. You may want a pump at each location, particularly if there are separate compartments. Plumbing: Most hose sold for bilge pump use is light plastic corrugated stuff [Ed: Specs, standards and recommended options for marine hose appears in DIY 2000-#2 issue.] Corrugations have the advantage of making the hose flexible enough to turn tight corners without kinking, but they also contribute a significant amount of resistance to water flow adding to the dynamic head pressure the pump must overcome. Each bend, elbow and hose length itself contributes to resistance. So, to minimize adverse head pressure the hose route should theoretically be as short as possible, rise as little as possible, have few bends and have no corrugations. The discharge thruhull must also be a safe distance / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 31 KEEPING DRY / Back page / Next page / Contents page / PUMP BY THE NUMBERS Owner of Galleon Jewelers and avid sportsfisherman, Captain Richard Provenzano may be considered somewhat eccentric when it comes to staying afloat. Moored in Sebastian, Fla., his 11m (36') Hatteras has weathered numerous hurricanes, floods and the like which he largely attributes to having seven pumps onboard. Starting at the bow are two in the forward stateroom, one 1,200 gph unit in the bilge and one 800 gph high-water pump mounted 15cm (6") higher that attaches to the drain sump from the shower. “When I’m shy on fuel, the boat’s bow heavy in the slip,” says Provenzano, “and if the lower pump fails, the boat won’t fill with water.” Mounted in the engine compartment are two 2,000-gph pumps under each engine. In the bilge below the companionway beside the Racor filters is a Lovett pump. “This one is the main pump.” Another two 1,500 gph pumps reside in the stern bilge. This gives a total pumping capacity of about 11,000 gph. “It’s a lot of pumps, but leaks happen.” — Jan Mundy above the waterline to avoid back siphoning. Back Siphoning and Check Valves: Some systems may have the bilge pump discharge installed below the waterline with a check valve to prevent back siphoning. If you do this, your boat will sink — it’s not a matter of if, just when. Every check valve eventually gets a bit of debris lodged in the flapper and when it no longer seals the boat sinks. Sailboats have particular difficulty finding a good above waterline location for the discharge simply because when heeled over in a stiff breeze the waterline on the - Ti p - leeward side may be up on deck somewhere. Conversely, an outlet on the windward side may now be 3.6m (12') straight up from the pump (Figure 5). On one tack the pump wants to back siphon and sink the boat, on the other tack the head pressure is so great it may not pump any water at all. There are three solutions: reef sails to reduce heel; lead the discharge hose to the center of the tran som, if you have access; lead the hose up to the deck head and install a siphon break or riser loop. Hopefully, the hose is now above the heeled waterline and the extra head pressure on the other tack won’t cripple the pump. Never install PUMP CYCLE METER About 10 years ago, Rockland, Mass., marine surveyor David McKie installed a bilge pump "minutemeter" on his boat. Developed by a local inventor, the analog meter mounted inline with the float switch and registered pump-operating time in minutes, similar to an engine hourmeter. Recording meter readings before leaving the boat and upon returning gave McKie an accurate audit of pump run-time. We’re not aware of any off-the-shelf products available, but if you’re handy with electronics, it’s a simple device to make. — Jan Mundy check valves for the reasons mentioned above. Powerboat manufacturers often install the bilge pump outlet a few inches above the waterline to avoid annoying sounds of water splashing. Beware of crowded cockpit parties where excessive weight can submerge thru-hulls. To avoid a back siphon, the discharge hose should be routed through a riser loop. Riser height is a compromise between avoiding a back siphon and decreasing pump performance. A 46cm (18") riser ought to be about right. If you hate the thought of drilling another hole in the hull for a thru-hull, it’s possible to tee the discharge into existing above-waterline outlets (i.e. cockpit scuppers or sink drains) as long as the hose rises high above the waterline and includes a riser loop. If in doubt, do not attempt. Finally, make sure all hoses can’t kink, are well supported and are all double clamped with non-corrosive clamps (see “Not all Clamps are Equal” on page 35). Batteries: Most submersible pumps draw about 6 amps of 12-volt DC current for every 1,500 gph of capacity. If your boat has a 90-amp battery at 80% charge (which is optimistic) you could theoretically run a 3,000 gph pump (or two 1,500gph units) for three hours before you use up half the available juice. The other half of the battery’s charge will be available at lower and lower voltages, so pumping efficiency will fall off rapidly. If you have the motor running or plugged into shorepower with the battery charger going, battery capacity is not a problem. If you are adrift with a disabled engine and taking on water, a good bilge pump system doesn’t mean much if your batteries can’t supply the needed power until rescued. There are only two kinds of marine batteries; / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 32 KEEPING DRY / Back page / Next page / Contents page / 3 5 4 2 1 7 6 1.Unlike submersible pumps that continuously cycle on and off, Rule Mate pumps have an integral float switch that turns the pump on only when water level rises. 2. Conventional float switch. 3. A high-water alarm triggered by an electrode provides early warning to irregular bilge water levels. 4. Ultra Pumpswitch has an non-jamming enclosed float and magnetic switch; Senior model features a high-water alarm 5. A "smart" bilge switch, the Bilge Buddy shuts off the pump switch when it senses petroleum products in the bilge; 6. Compact and quickly assembled when needed, Edson one gallon-one stroke portable pump kit includes carrying board and quickconnect couplings. 7. A manual override switch or a three-position on off auto switch lets you manually pump out the dregs and override a stuck float switch. cranking batteries or deep cycle batteries, which cost two to three times as much but last five times as long. Don’t skimp on batteries if you want your pumps to keep your boat afloat in an emergency. Wiring: Bilge pumps are probably the only electrical item that should remain powered even when the main switch is turned off. Wire directly to the battery terminal or more neatly to the battery connection post(s) on the back of the main switch. Pump performance suffers a lot from small voltage drops due to line losses, so when specifying wire sizes, ABYC 3% voltage loss tables should be used (refer to “Wiring Handbook,” DIY 1998-#4 issue). For example: a pump draws 15 amps and you need 9m (30') of conductor to power it, the tables specify 8 gauge AWG wire to keep voltage losses within 3%. Making durable connections to the float switch and pump is always a problem in an area that is often wet, particularly in saltwater. Corrosion at these connections is the most common cause of pump failure. Corrosion increases electrical resistance, which in turn can cause a connection to overheat or break. Bilge pump wires and connections must be watertight, preferably crimp-on connections with self-adhesive, heat-shrink terminals. No wire nuts (Marette plugs) or tape. Specialty UL-approved multi-strand Boat Cable (or BC) is available for bilge pumps (two or three colorcoded conductors 18 to 14 AWG with water-resistant jacket). All connections should be above the maximum bilge water level or as high as possible, fastened securely and away from float switches, control cables, shafts, etc. Fuses: Corroded fuses and fuse holders are the next most common reason pumps won’t go when they ought to. Because of this weak link, some surveyors even disagree with ABYC recommendations that a fuse or breaker should protect this circuit, like all others. Submersible pumps can overheat and even melt but rarely catch fire. The big danger here is a short circuit in wiring to the pump causing a fire. To minimize that possibility and preserve circuit Figure 5 DAVID AIKEN SYSTEM COMPONENTS Static head varies in sailboats when heeled and siphoning potential varies depending on the tack. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 33 KEEPING DRY protection keep any in-line fuses out of the bilge and in the closest available location with quick access. Check and clean terminals often, and replace fuses every year regardless. Automatic Pump Switches Generically known as float switches, there are many different kinds available. All of them can malfunction and frequently do, most likely from oily, hairy, slimy debrisfilled sludge that inhabits most bilges. Switches become so badly fouled that they clog or stick. If stuck in down position, the boat might sink. If stuck in the up position, your pump runs on and on until it eventually burns out or flattens your battery — then the boat sinks. The first step in keeping the float switch and pump alive is to keep your bilge clean and free of debris. Maybe it’s time to add a drip pan under the engine [Ed: refer to DIY Projects, 1996-#4 for how to build one] or a separate graywater sump for the shower. Don’t pump fuel — or oil-mixed bilge brew overboard. It pollutes and is illegal in many areas with fines up to US$5,000. If the bilge sump is narrow and long enough to allow a few inches of water to surge back and forth it can beat relentlessly on an exposed float switch until the hinge or wires break. If your boat has this sort of layout you need a switch housed in a protective cover (which unfortunately can foul up) or install a cheap baffle to protect the switch. Installing the switch near a bulkhead with the hinge facing the surge will also help protect it. Wiring inside a switch not rated to carry the same amperage as the pump draws, will overheat, causing premature failure due to fatigue or corrosion. In a sailboat the float switch must be on the same fore-aft axis as / Back page / Next page / Contents page / the pump, otherwise it won’t operate in the same depth of water when the boat heels. This causes the pump to run dry on one tack, yet not trigger the pump when needed. Although a switch will work installed on a pump’s either positive or negative feed, don’t install it on the negative side. This leaves the pump energized at all times. In saltwater there is a high risk of stray current leaks to ground. Any current leak from the pump will destroy it and possibly any metal thru-hull, which provides a path to ground. Proper bonding of thru-hulls will delay but may not prevent damage from stray current galvanic protection. [Ed: DC bonding systems and corrosion will be covered in upcoming issues.] Make sure the float switch is set up to shut down the pump long before it begins to suck air, otherwise it will either never shut off reliably or water remaining in the hose will drain down and re-trigger the switch, setting up an endless cycle. You may need to choose a switch with a larger vertical distance between the trigger points for on and off Some panel switches have a provision to show an indicator light when the pump is activated; you may otherwise be unaware that the pump is working. Another useful gadget available is a cycle counter so you can gauge typical daily or weekly pump use and look for any sudden jumps in pump activity that may indicate a packing gland beginning to leak or a bad plank seam. Another potentially useful accessory is a high-water alarm, such as a separate unit that’s triggered by a secondary float switch or by the backup pump. If you are away, a high-water audio alarm or flashing light can also alert your dockside neighbors or marina staff that your boat is in trouble. [Ed: - Ti p EMERGENCY AUX PUMP A raw-water cooled inboard engine is easily converted to double as an emergency bilge pump. Installation requires three valves, a couple tee fittings and hose connections. You’ll find complete how-to instructions and configuration options in "Modifying Rawwater Cooling Systems," article in DIY 1997-#3 issue, now available in PDF format @ DIY ONLINE — Jan Mundy Consider upgrading to one of the newer, high-tech switches, such as the electronic "smart" Bilge Buddy or magnetic Ultra Pumpswitch. These self-contained, non-jamming switches cost as much as $100 more than a standard "cheap" float switch — buy the best you can afford.] Conclusion There is no fail-safe bilge pump system that will keep you afloat in all circumstances. It’s important to understand the capabilities and limitations of your own system and never take it for granted, especially any automatic system. While underway, there is no substitute for regular manual checks of bilges as part of normal watch keeping. When at a mooring, no automatic system can ever substitute for weekly visits to your boat just to make sure it’s afloat. About the author: Nick Bailey is service manager of Bristol Marine in Mississauga, Ont., and an avid Thunderbird-class racer. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 34 PLUMBING 101 / Back page / Next page / Contents page / NOT ALL CLAMPS ARE EQUAL Hose clamps vary greatly in quality and construction. What you may think is an "all-stainless" clamp could sink your boat. By Jan Mundy Replacing a failed submersible pump in one of our 6.6m (22') test boats prompted an investigation into hose clamps. You’ll note in the photo (left) the badly corroded clamps connecting hoses to belowwaterline thruhulls not equipped with seacocks. Like most boaters, we hadn’t examined the clamps until the need arose. Besides saltwater (this is a freshwater-used boat), cleaners and chemicals in bilge water can and do accelerate corrosion of isome metals. Clamp failure in the bilge can sink a boat; clamp failure on a fuel line can be fatal. Close inspection of five brands, four obtained from marine stores and one removed from our test boat, netted surprising results. Many clamps sold are not all 100% corrosion-proof Two hose clamps (left and stainless-steel construction. center) with magnetic, Stamped on every clamp potentially corrosive screw screw was "All Stainless," pins and housings stamped yet the clamps in our test "All-Stainless" purchased from a local marine store, boat had badly rusted screws and corroded bands and clamp (right) removed from test boat. Perforated underneath the screw bands encourage crevice housings. corrosion and are prone to Although clamps may cracking. be labeled all-stainless, there are different grades of stainless; clamps are commonly made of 304, 316 or 400. Series 302, 304 and 305 stainless, commonly referred to as Only two of five 18-8, are non-magnetic, "all-stainless" but freely succumb to clamps passed the magnet test: AWAB crevice corrosion. More and Ideal All 316 SS. expensive is non-magnetic 316, a lower carbon, higher nickel and chrome content stainless which makes it more corrosion resistance. Type 400 stainless is magnetic and corrodes rapidly in the marine environment. Our magnetic test found three clamps with magnetic screws and housings, which means they are highly corrosive. Two clamps, AWAB and Ideal All 316 SS held no attraction. Our tests prove that boaters once again must be aware of what they’re buying, and when it comes to purchasing clamps, look for either AWAB or equivalent "All 316 Stainless" clamps. You’ll pay more, but it’s unlikely you’ll have to replace them. When in doubt, carry a big magnet. Lastly, contrary to popular belief, tighter is not better. Use the manufacturers recommended tightening torque, typically 45 to 55 inch-pounds, or secure as tight as possible with a screwdriver. Using a ratchet or socket wrench overtightens clamps and damages hoses. Details of a premium hose clamp: all-316 non-metallic, noncorrosive stainless; solid non-perforated band prevents metal fatigue and breakage, and uniform clamping force; stamped band threads on outside offer high clamping force; smooth band inside with no perforations and rolled edges prevent hose damage; pin housing designed to maintain circular shape. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 35 PLUMBING 101 BILGE PUMP SENTINEL Easy to add to an existing system, this simple alarm sounds every time the bilge pump cycles. By Paul Shard This may be the most important upgrade you add to your boat — an alarm that sounds when your automatic bilge pump cycles. Water flow from a leaking stuffing box or parted hose-clamp can quickly overcome a pump, a plight that can continue undetected, as the boat sinks lower in the water. Numerous cases have been reported of boaters opening the hatch, stepping down into the cabin into a foot of water. With hundreds of gallons sloshing in the bilge, it becomes very difficult to find the source of the leak. The solution is to install an audible bilge alarm. Any water in the bilge is detected immediately. The alarm should be audible both in the cabin and on deck, even when the engine’s running (alternatively, consider more than one alarm). If you already have an electric pump with a separate float switch, an alarm is added easily. If you don’t have an automatic pump with float switch, it may be a good time to install one. To connect an alarm to an existing bilge pump switch, purchase a 12-volt DC alarm from a marine or electronics supply store. Models with indicator light and buzzer are usually mounted in a panel. Buzzer-only units can be mounted anywhere within hearing range. A location near the bilge pump switch simplifies wiring. Wire the alarm’s hot (positive) lead to the terminal on the back of the bilge switch that manually turns on the pump (Figure 3, B on page 30). This terminal also has power to it when the float switch turns on the pump. Connect the other wire to a negative bus bar. Now test the system: switch the bilge pump to manual or lift the float switch to activate the pump. Every time the float switch turns on the pump, the alarm also sounds. Some boats have “intelligent” bilge pumps with integral float switch in the same housing. Some models (Rule Mate) are wired with a manual override. If not so equipped, the easiest option is to add a separate float switch and alarm. Mount the float switch above the existing automatic switch so the alarm sounds when water rises above normal. One alternative, if you have room in the bilge, is to / Back page / Next page / Contents page / install a smaller second pump with an alarm (as described above) but mounted lower in the bilge. Now this pump sounds the alarm when it detects water; the original pump becomes a backup. Boat motion may occasionally activate the switch then turn on the pump and alarm, though no water is actually pumped overboard. On a rough day, this gets annoying. Commonly caused by a poorly designed float switch or improper mounting, raise the switch slightly higher than the pump. If this doesn’t resolve the problem, consider a switch with a larger vertical distance between the trigger points, such as the Ultra Pumpswitch, Groco Bilge Pump Control Kit or other ones that compensate for backflow without activating the switch. Installed on our 37-footer, “Two-Step,” this alarm system has been problem-free for 10 years and 35,000 miles of international cruising. On four occasions it alerted us to potentially dangerous problems. One time the dripless shaft seal had jammed with debris when we put the motor in gear and water was pouring in. It was easy to fix since the water level was still very low in the bilge and I could see the spray leaking out the seal. Occasionally the alarm activates in the middle of the night, usually after a heavy rain. Personally I don’t mind hearing it cycle on for a few seconds, then go off again. It’s when it comes on and stays on I take action. Altogether, it’s the cheapest stay-afloat insurance we have on board. About the author: Paul Shard and his wife and business partner, Sheryl, are the authors of “Sail Away! A Guide to Outfitting and Provisioning for Cruising” published by Pelagic Press. You can follow their adventures at www.searoom.com. - Ti p - LOSS COVERAGE If your boat should sink are you insured? A loss due to “unknown” causes will likely be covered by the insurance company. Should a survey prove that the sinking was due to lack of maintenance or negligence, it’s possible your claim might not be covered. Check your policy now for “exclusions” ere you need to file a claim. — Jan Mundy / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 36 PLUMBING 101 BILGE PUMP REPLACEMENT By Jan Mundy Boatbuilders often mount bilge pumps in inaccessible areas deep in the bilge, usually before the deck is in place, unmindful of replacement or servicing. Particularly in small powerboats, replacement demands crawling through a small hatch, often working blind. (Use a mirror for a rearview look if you’re adept at working backwards.) Submersible bilge pumps typically run for nine years before failure and less for leaky boats where the pump regularly cycles or dry boats, where lack of use causes corrosion or grit, sand or salt build-up. Failure also occurs when water gets into the pump through wires or shaft seal — the pump fills with water then goes through several freeze-thaw cycles. This was the case with a Mayfair pump in one of DIY’s test boats when it failed to run after 10 years of normal use in freshwater. Replacement is an easy one-hour job, after removing the old unit, drying the bilge and sealing the original mounting holes. 1 If you’re lucky, the original pump has a detachable base, so removing mounting screws is easy. The Mayfair unit didn’t; removal meant dangling in a narrow stern locker, groping with hands, trying to locate three Phillipshead screws. For bilge work, an extralong handled screwdriver comes in handy. Note the corroded hose clamps in the photo (above). / Back page / Next page / Contents page / 2 Since pumps rarely have the same footprint, the next step is to seal the original mounting holes with 3M Premium filler, 3M 4200 (I prefer the Fast Cure) 5200 or equivalent brand. Be sure holes are dry before filling. While you’re down there, inspect the hull for other openings in the hull and properly seal. I found a few extra holes drilled by the manufacturer, none were sealed. (The very first item on your to-do list after purchasing a boat, either new or used, should be to rebed every piece of hardware, caulk voids, holes, etc.) 3 Placement of pump and switch is critical. Even when replacing, it’s best to doublecheck the location. Position the pump base (strainer) so the nozzle aligns with the discharge hose and locking tabs line up with the pump body. The float switch should mount at least 6mm (1/4”) above the strainer so it’s not automatically running all the time. Rule pumps come with an adapter that connects the switch to the pump base and positions the switch at the proper height. Pumps are prewired and include fasteners; you’ll need to supply sealant and heat-shrink connectors. 4 Carefully drill a pilot hole in the hull for the pump base, liberally caulk around the hole, then fasten base with supplied screws. Don’t drill through! Never mount base directly on a cored hull — a leaking fastener can quickly delaminate cores below the waterline. Instead, install a hardwood (teak or mahogany) backing block, then attach base to block. 5 Connect the hose, double clamp (if enough clearance on hose barb) and install the pump switch. 6 You have an option of wiring the pump for manual or automatic operation. Since this boat already had an automaticmanual pump control, we stripped the lead ends, connected negative and positive ends to the original wires leading from the panel and battery, routing the wires high, just underneath the deckhead. Ends were crimped together using adhesive-lined, heatshrink connectors. If you don’t have any, seal the connectors with sealant. Note: positive lead from bilge pumps should connect directly to the positive battery post so as not to accidentally disconnect with the master switch. Also, all pumps must be fused and with the proper size fuse or a pump may overheat and blow a circuit. The original pump installation included an in-line 6-amp fuse, the new Rule pump required a 9-amp fuse. 7 Not included but recommended is a protective float switch cover. For extra reliability, add a second switch mounted slightly higher. Better yet, add a second pump. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 37 PLUMBING 101 / Back page / Next page / Contents page / WHAT YOU SHOULD KNOW ABOUT HOSE Hoses are essential to keeping your boat afloat and operative but many boats are equipped with inferior, non-marine-rated hoses. Here’s how to survey and upgrade your boat to comply with today’s performance and safety standards. Story and photos by Jan Mundy M any boats built before 1990 and some after, were assembled from readily available materials, such as highly corrosive automotive wiring, inexpensive heater and fuel line hoses and household plumbing fittings, with little concern for boatbuilding standards, either mandatory or voluntary. Nowadays, the installation of most boat systems are regulated by the Coast Guard, American Boat and Yacht Council (ABYC), National Marine Manufacturer’s Association (NMMA), Lloyd’s and others. Though some standards are voluntary and not always adopted by boatbuilders, you should adapt these when replacing or upgrading components. This ensures your boat will, at the very least, pass a survey or insurance claim if the surveyor or adjuster is standardsliterate, and you can avoid failures Certified hoses for use on boats: (top) Hard-wall (“R2” designated), wet exhaust and water intake hose, SAE J2006 rated; (middle) Coast Guardcertified fuel fill hose that meets fire resistance (“A”) and lowest fuel permeation (“2”) standards; (bottom) Certified fuel distribution and return hose meets fire resistance (“A”) and highest fuel permeation (“B”) standards. Gasoline-powered boats must have certified fuel hoses to pass a survey or insurance claim when done by a competent surveyor or adjuster. Non-approved automotive hoses installed in early ‘80s on author’s 7.5hp diesel engine: (top) cheap, highly-abrasive corrugated fuel fill shown on right side; very thinwalled, non-Coast Guardapproved fuel distribution line; common heater hose for rawwater exhaust shown on left side. Note split hose wrapped over soft heater hose (left side) to protect from abrading on bulkhead. (bottom) Automotive heater hose connects to exhaust manifold. All hoses have since been upgraded to marine spec after researching for this article. by inferior products. Attending a seminar presented by Bill Shields of Trident Marine at IBEX ‘99 (a trade show for boatbuilders), prompted me to inspect the hoses on my own early-‘80s-built boat. What I found wasn’t pretty and unsafe, especially engine hoses. If you haven’t upgraded hoses on your boat lately, read on. Hose approved for marine use should be Coast Guard certified, as required for gasoline-carrying lines, or constructed to meet minimum performance and quality standards. Though generally more expensive than non-marine-rated hose, using such products insures greater service life and safety. Consider these examples. When a raw-water-cooled engine develops a blockage and the engine overheats, an automotive heater hose would likely burst. Spill solvent on a cheap PVC hose and it quickly dissolves. A ruptured nonmarine hose on an engine or gen-set raw-water connection, air conditioning, bilge pump, head and livewell intakes or any hose connected to a below-waterline thruhull can sink your boat. Likewise for a leaking cockpit drain hose — should it rain and the bilge pump can’t keep up with the water flow, the boat will surely sink. Non-standard engine exhaust hose with pinhole leaks can result in deadly carbon monoxide poisoning and possible flooding. Breach an unrated diesel fuel line or holding tank hose and you’re guaranteed to have the contents dumped into the bilge, creating a very dangerous, or noxious, situation. Blow a non-certified gasoline line and the boat becomes an explosive shell. Hoses for marine use are often labeled with the standards classification, either SAE, Coast Guard, NMMA, ISO, UL or Lloyd’s; the manufacturer’s identification number, usage, the year manufactured plus other classifications as specified for each particular application. When purchasing approved hose, also examine the construction: check that the hose ends have the same inside / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 38 ABOUT HOSE (left) Very soft, non-reinforced automotive heater hose commonly found in older boats and on author’s boat for raw-water engine intake. (right) Overtightening the hose clamp has resulted in the thin-walled automotive heater hose being crushed. A hose failure could sink this boat. diameter; examine the wall thickness as thin-walled hose easily kinks and has poor abrasion resistance; and check that it’s reinforced with wire or synthetic yarn (usually polyester). Now that marine-rated brandname hoses are readily available, it makes good sense to purchase the best you can afford and of the proper material and strength rating. Since doing the research for this article, I’ve replaced all the automotive engine hoses on my boat and now have premium quality, smell-free head hoses. Next time you’re onboard your boat, I suggest you inspect all the hoses and upgrade, based on the following specs, as needed. Fuel Hose Gasoline-carrying hoses on inboard and stern drive boats are the only ones that must by law meet Coast Guard standards. Look for hoses labeled “SAE J1527,” or less common, “UL-1114.” Labeling on fuel hoses also includes: classification of resistance to fire, either “A” for fire resistant, “B” for not fire tested (for outboard use only); and fuel permeation, either “1” which is the Wall thickness of Coast Guardcertified fuel line hose (pictured) is more than twice the thickness of automotive fuel line. / Back page / Next page / Contents page / highest permeation requirements for gasoline distribution and return lines, or “2,” a less-stringent requirement commonly used for gasoline fuel fill and vent hoses, and all diesel hoses. There are currently no mandatory standards for diesel or outboard engine applications. Exhaust Hose Since 1999, flexible rubber hose, bellows and elbows used in wet exhaust systems must comply with SAE J2006 standards and be so labeled. This means that the hose is temperature-rated at 593°C (1,100°F) for two minutes, the equivalent of running the engine at full power for two minutes. Wet exhaust hose Vetus double-steel reinforced rubber should also exhaust hose is very be flexible, flexible, has Lloyd’s thick Register of Shipping walled, and approval and rated for resistant to 100°C (212°F). cold, heat, abrasion, antifreeze and oil. Various compounds are offered depending on application and your budget. The less expensive high-temp black 100% EPDM rubber withstands 121°C (250°F) maximum continuous. More expensive is 100% silicone hose with polyester reinforcement and molded silicone-EPDM blend withstands 176.6°C (350°F) maximum continuous. For extreme high-heat applications, premium-priced NomexExtra thick-walled engine coolant hose (or for drain or sanitation uses) with wire helix between two-ply reinforcement has excellent flexibility and bend radius. molded or -reinforced 100% silicone rated for 260°C (500°F) maximum continuous lasts up to six times longer than economical black EPDM rubber hose. Additional labeling on some brands rates the product’s flexibility: “R” for soft-wall, “R2” for hard-wall, and “R3” for exhaust connectors. Softwall hose, commonly used for straight connections, is reinforced with multiple yarn plies. Hard-wall hose is wire- and yarn-reinforced, preferably wire sandwiched between two plies. Flexible elbows and hose bellows with an “R3” rating easily mold into the tightest bends to compensate for engine movement, vibration, noise and misalignment, and reduce engine back pressure. Engine Coolant Hose Hoses that circulate engine coolant water must resist kinking, heat, antifreeze and oil. A heavy-wall, twoply rubber hose, with or without wire reinforcing, is recommended, or substitute premium automotive black heater hose or blue silicone hose, both rated to meet SAE J20 standards. Some coolant hoses are also reinforced with synthetic yarn. For high-temp applications, Trident’s Premium Blue Silicone hose has a maximum continuous rating of 287°C (550°F). Raw-Water Pick-up Hose Any hose connected to a thru-hull located below the waterline that delivers raw water to an engine, head, air conditioning and livewell should be the best hose purchasable. Don’t rely on corrugated hose — a rupture could sink your boat. There are no standards for this hose, though it’s recommended to use two- ply, wire-reinforced, heavy-wall rubber hose, the type used for engine exhaust (SAE J2006 R2 or / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 39 ABOUT HOSE / Back page / Next page / Contents page / equivalent). Such hose won’t kink nor collapse under suction if the rawwater screen becomes clogged. Potable Water Hose According to ABYC and NMMA standards, water hoses must be foodgrade or FDA-approved, usually PVC (polyvinyl chloride), preferably smooth-walled and opaque rather than clear as light encourages algae growth. Never use rubber hose as it imparts a foul smell in the water. Pressurized cold-water systems require reinforced hose for water distribution, typically a clear or white hose with red, blue and/or white polyester yarn tracers. Both pressurized and non-pressurized hotwater systems, where lines carry 60°C (140°F) water or higher, require reinforced rubber hose. Water tank fill and vent hoses commonly use smooth-walled rigid hose. Alternatives to hose for all applications are rigid household-type water pipe (different types for carrying cold and hot water) and piping systems offered by Whale and Flair-It. (For detailed information on Cheap multiflex corrugated hose collapses in suction applications, ruptures easily and reduces water flow by up to 30%. cuffs, is the worst option for bilge pump intakes or for connecting pumps to thru-hulls. Sure it’s resistant to oil, water, easily bends around tight corners and lasts a long time. But kink it and the hose cracks. Chafe it and it punctures. And the corrugations and cuffs reduce water flow by 30% and higher. (For more information on bilge hose and water volume, refer to DIY 2000#1 issue.) Most quality boatbuilders have replaced corrugated hose with a more durable nearly-as-flexible smooth version. Drains Flexible, heavy-walled rubber water intake hose that doesn’t kink or abrade is recommended for cockpit, sink and shower drains. Alternatively, you can use smooth vinyl or PVC tubing, depending on the installation. Sanitation Hose (top) White PVC smooth-wall hose commonly used for head and potable water applications; (middle) Premium choice odor-resistant, heavy- and smooth-walled, reinforced, premium black rubber sanitation hose; soft-wall portable water hose reinforced with multiple yarn plies, commonly used for straight connections. installing and troubleshooting freshwater systems, refer to DIY 1997-#1 issue.) Bilge Hose Cheap multi-flex corrugated hose, the stuff with the equally spaced molded Sanitation hose on boats must contain sewage that is about 30 times more Use a smooth wall, wire-reinforced hose (top) first to do the job before selecting the cheaper, corrugated hose (bottom). concentrated, especially vacuum-type toilets that have very low water content, than residential sewage. This is not an easy task. Such hose must be flexible, kink-resistant and more importantly, odor-resistant. Often the only type offered in marine stores, and commonly installed on boats, is food-grade, smooth-walled white PVC. Not the best selection as odor permeation is commonplace –- before upgrading, I replaced cheap head hoses every season as part of my spring commissioning chores. Stink-resistant alternatives, but not readily available, are gray antibacterial hose and the smooth, heavywalled, premium-grade, less odorous, black rubber hose. Either is a better choice than conventional PVC hose, but about twice the cost, however, they won’t need replacing as often. Some boat owners have had good success with Schedule 40 or Schedule 80 pipe, supported every 1.8m (6'). Installing short hoses, minimizing connections and limiting use of Yvalves that can trap sewage also helps to reduce odor-causing problems. (For step-by-step head and holding tank installations and troubleshooting, refer to DIY 1997-#2.) Although there are no recommended standards for sanitation hose, it’s often labeled with the type and manufacturer. Knowing this information helps to identify your replacement options. Ducting Factory-supplied flexible vinyl ducting used for heat and air conditioning systems punctures easily. Better to replace it with more durable, heavierwalled ducting. Propane Hoses used onboard for propane appliances must comply with UL 21 and must be assembled with swaged end fittings. All installations must comply with ABYC A1. / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 40 PLUMBING 101 / Back page / Next page / Contents page / HOW TO PLUMB BENDS Plumbing a bilge pump, cockpit drains, sink or thru-hulls often necessitates bending hose at acute angles. Most rubber water hose collapses when tightly bent, and the cheap multi-flex corrugated stuff that does bend punctures easily and should never be used in critical installations. Vetus exhaust hose is the perfect solution. Form this hose into a tight coil and it retains its inside diameter without crushing or kinking. Unlike other exhaust hose, it can be used in pressure applications. The 50mm (2") hose, for example, is rated for 174 psi (or 12 bar). It’s available in various diameters starting at 30mm (1-3/16") ID. Vetus black exhaust hose (look for the yellow stripe) is expensive at US$8 per foot for the 50mm (2") size, but a better option than using inferior hose or PVC tubing and adding elbows. — Jan Mundy / Back page / Next page / Contents page / © DIY boat owner 2001 1-888-658-2628 41