Wreck Discovery - Read the SCUBA article
Transcription
Wreck Discovery - Read the SCUBA article
LEARNINGCURVE Wreck discovery Wrecks come in every shape and size, but all have certain principal features. Charter skipper Bob Anderson sheds some light on the machinery you are likely to see, painting a picture of what can be found on a typical wreck he sea does strange things to time. As soon as a ship slips below the waves her history is paused and a new future starts governed by the salty water and other destructive forces of nature. The coast of the UK is littered with wrecks: Ian Whittaker’s book Off Scotland charts the position of every recorded wreck in Scottish waters as a black dot on a white sheet of paper. The coastline can clearly be traced from this information alone. Wrecks are the very raison d’être for many who dive, yet they are strangely misunderstood. In my mind, much of this confusion arises because people complicate wrecks more than necessary. The way to understand and interpret a wreck lies in simplifying the structures common to all vessels and having an understanding of their role in the ship. Most divers jump off a boat to get to a wreck, so a simple glance around before you jump can help. There is a wealth of information about most sites that can be soaked up before entering the water so, in many ways, a wreck dive should be a confirmation of T 50 what is already known rather than a voyage into the unknown. Underpinning everything is a simplicity of function that really brings things alive. Three-castle steamships A good starting place is the classic steamship. The Sound of Mull has several firm favourites and the Shuna and the Hispania rank as among the best in the UK. Usually with a tonnage of around 1,200 and about 80m long, these ships were built to carry a bulk cargo, commonly coal, in a number of cavernous holds. On top of the hull were three castles (a term inherited from old sailing ships): the forecastle or fo’c’sle at the bow, the bridge and engine room in the middle, and the poop at the stern. Underneath lie the engine spaces and cargo holds, which take up the majority of the space on the ship. A hull has a design speed at which it will efficiently cruise through the water, which is a function of waterline length. Yachts and warships tend to be long and sleek in order to maximise speed, while steamships favour a more bulbous, bellied hull to maximise internal cargo carrying capacity. The bows of both the Hispania and the Shuna in the Sound of Mull are bluff, flat-nosed affairs that flow to the full beam of the ship swiftly with little hydrodynamic grace. Yet at the stern, these ships have a beautiful curve that is a characteristic snapshot of their age, a shape that has all but gone from modern ship design. Dropping over the stern rail of a ship and down to the prop and rudder always conveys a good sense of scale. There is nothing quite like seeing the blades of a massive prop to make you feel small. RAbove: Rising up the bow of a classic steamship, Norway's Helga Ferdinand However these often, large lumps of valuable non-ferrous metal are easily removed and so many are simply not there. The Shuna, luckily, has a ferrous prop and so it remains. UBelow: The typical layout of a three castle steamship The bow and anchors The front island, or fo’c’sle, is a legacy from fighting ships of old where there literally was a castle at the bow that allowed archers to fire down on the enemy. This part of the ship slowly evolved into the bosun’s stores below deck and the anchor winch topside. The Shuna’s crew attempted to run the ship up the beach and hold her there on the anchors. Sadly they failed and the ship slipped back down the slope to where she ILLUSTRATED MARINE ENCYCLOPAEDIA 1890, PAASCH, H lies today. The evidence for this story is there today as the rusty remains of the anchor chains can just be made out in the silt at the bottom of the bow and the anchors are not housed in their normal positions. Ships’ anchors are generally stowed in the sides of the hull at the bow. The chain goes through the hawse pipe, from the outside of the hull to the deck, running over thick rubbing plates to the anchor windlass. From the winch it will run over a gypsy (which is a shaped ‘wheel’ that raises the chain as it turns) before running down a spurling pipe down into a chain locker where it is stowed. The main remains of the modern wreck of Lunokhods in Shetland is a bow section that has snapped off from the rest of the ship g 51 LEARNINGCURVE RAbove: A diver is dwarfed by the massive iron blades of the Shuna g but, despite the modern details, it shows that the principles of anchor stowage have remained unchanged. The bosun’s stores in the bow are usually in a compartment just below the anchorhandling area and frequently hold interesting arrays of ship parts or other stores. In both the steamships in Lerwick harbour, the stores still have the remains of blocks wires, ropes and other tackle slowly rusting away. I always like to swim off a wreck at the g SBelow: The stern of the Hispania is a flow of beautiful lines RAbove: The Lunokhods is a modern ship but the principles remain the same: a diver illuminates the anchor winch while a rope drum to the left tidies away the warps while at sea RAbove: The bows of the Glen Isla sail out of the depths – there is no better feeling than slowly rising up the bow of a classic steamship 52 g LEARNINGCURVE g bow before turning and looking back. There is often a panorama to soak in that gives a full sense of the ship and her character. The cargo and holds Within the hull lies the cargo. Coal is the most common find, as it is a bulk commodity needing to be moved in large quantities over considerable distances. The Shuna has holds full to the top, still fully laden even on the seabed. Of far more interest is a ship with a good variety of mixed goods such as the Breda. Twelve divers can happily scratch around the holds like hens in a pen, searching for some RAbove: Exploring the coal in the holds of the Shuna of its vast array of goodies, each wrapped in their own smoky cloud of silt. Salvage plays a part in what you see of the holds, as the manifest was often the most valuable component of a ship. The SS Buitenzorg, which lies deep in the mouth of the Sound of Mull, was salvaged and the hatches from the holds were ripped open, releasing the bundles of raw latex rubber which then slowly floated to the surface. The bundles could take hours to reach the surface, by which time the tide had taken g SBelow: A naked hermit RAbove: A squat crab runs across a pile of white bathroom tiles lobster has made his home from gas mask eyepieces fallen from their rubber mask SBelow: Bicycle tyres slowly rot in the hold of the Breda RAbove: An anemone has found a home on a tube of rubber glue 55 LEARNINGCURVE g them miles from the site: many locals will tell the tales of setting off in hot pursuit. The bridge The middle castle on our idealised steamship is the bridge atop the main accommodation area. It is well worth visiting the SS Great Britain in Bristol where there is a bridge from one side of the ship to the other that forms a raised platform for command, which shows the origin of the term very well. This is one area that has changed beyond recognition over the years. In times past there would have been a single sailor steering a ship by compass at a solitary wheel, whereas modern ships can have a bank of complicated electronics forming a wall of monitors that the skipper does well to see over. On wrecks, the bridge draws divers in with the glitter of brass. Many of the favoured items for salvage are grounded in this area, from compass binnacles to the ship’s wheel and other brass bounties. The steering binnacle from the Glen Isla, for example, has been recovered and is now in the Shetland museum; the feet are formed from three dolphins, a popular theme of the time. Many ships had a wooden bridge on top of a steel accommodation block so often the only indication is the solitary helm posting and the central boss of the wheel, a lonely sentinel on the roof of the wreck. In many ways, it is the crew area below the bridge that holds most interest. The stubs of table legs emerge from the mud, debris such as drawer fronts and other bric- SBelow: Exploring the triple expansion steam engine of the Glen Isla a-brac rise tantalisingly out from the ooze. Behind the mess, is usually a bathroom area with tiled floors, sinks and baths with taps hanging from the walls. If there ever is to be a touch of humanity on a wreck, it lies here. The engine room The engine room is one of the few places you can see the technology of the day stopped and frozen in time. Admittedly all the parts are corroding and slowly falling apart but these are not sterile museum surroundings: with care you can wriggle among the exposed con rods, trace the SBelow: A steam SBelow: Swimming engine before time and salt take a toll between the boilers of the steamship Gwladmena. ILLUSTRATED MARINE ENCYCLOPAEDIA 1890, PAASCH, H pipework and, if you are lucky, see the engineer’s spanners sitting next to the vice on a workbench. There is a Fred Dibnah within us all that can see the aesthetic, if not mechanical beauty in a place where form truly follows function. The Shuna has an often-overlooked engine room that many manage to miss, in the less than glowing viz that shrouds the wreck. Yet this is a gem of an engine, all the parts laid as they were in service with room to shine a torch around corners. Further north, the Glen Isla stands out even more: all the components are visible from g 57 LEARNINGCURVE TBelow: Though slightly reshuffled by the ravages of time, all the major organs of the Gwladmena are on show from the engine in the front to the two boilers behind PRight: Shetland is eclipsed by some of the wrecks in the colder Norwegian waters. Here a diver peeks into the open hatch of a steamship engine room UBelow right: Auxilliary steering wheel at the stern of Norway's DS Tyrifjord g the boilers to the engine, pipework, valves and engineer’s cabin. The stern In the past, the aft castle was the poop deck from which the boat would have been helmed. However this function has moved forward to the bridge over time, as the tiller has given way to a wheel. Yet the area often still holds some form of emergency auxiliary steering above the rudder shaft. The picture of the Breda that I like the best shows her from the stern steaming through what I imagine to be the Suez canal. I picture a salt worn Dutch seaman pausing for a cigarette over the stern rail before throwing the stub into the ship’s wash with a rasping cough and the slow drawl of a man too long from land and too battleworn to go home. The stern is very characteristic on the Breda and it is easy to 58 59