Study of Designing and Manufacturing Floating Dock

`
University of Khartoum
Faculty of Engineering
Mechanical Engineering Department
Study of Designing and Manufacturing
Floating Dock
A thesis submitted in partial fulfillment of the requirements for
the degree of B.Sc. in Mechanical Engineering
Presented by:
Name
Index
E-mail
Moiz Osama
105087
Mizokajee92@gmail.com
250501
Omerelctra574@outlook/
Mohamed
Omer EL-tayeb
Mohamed
Omer Abdullah Idris
com
105053
Omer_taichou8@hotmail
.com
Supervised by:
Dr. Dina Mohamed Bilal
1
‫‪August 2015‬‬
‫إهداء‬
‫إلى أمي وأبي‬
‫إلى أهلي وعشيرتي‬
‫إلى أساتذتي‬
‫إلى زمالئي وزميالتي‬
‫إلى الشموع التي تحترق لتضئ لآلخرين‬
‫إلى كل من علمني حرف ا‬
‫ِّ‬
‫ِّ‬
‫ب ِّ‬
‫ك‬
‫أَش ُ‬
‫أَن ْ‬
‫أَِّْخ ْلنِّي بَِّر ْح َمتِّ َ‬
‫ك َر نِّ ْع َمتَ َ‬
‫ك الَّتِّي ْ‬
‫أَن ْ‬
‫أَع َملَ صَالحاً تَ ْرََاُُ َو ْ‬
‫ت عَلَيَّ َوعَلَى َوالدَيَّ َو ْ‬
‫أَوزِّ ْعني ْ‬
‫ق ال تعالى { َوقَالَ َر ِّ ْ‬
‫أَن َع ْم َ‬
‫فِّي عِّب ِّ‬
‫اْ َ ِِّّ‬
‫ين }النمل‪.91‬‬
‫ك الصَّالح َ‬
‫َ‬
‫الشكر والمنة والحمد هلل أوالً على ما هدى ووفق وسدْ‪ .‬ف إني مدين بالشكر لكل من قدم إلي يد العون خالل‬
‫مسيرة تعليمي من أساتذة وأق ارب وأصدق اء‪ ،‬وارشدني في كتابة هذا البحث المتواَع ف لهم مني الشكر والتقديربعد‬
‫شكر هللا عز وجل‪.‬‬
‫الشكر والعرف ان للدكتورة المشرف االول ‪ْ /ْ.‬ينا بالل التي اشرفت على هذا البحث منذ أن كان فكرة وكذلك يطيب‬
‫لي أن أشكر المهندسة رندا عبد الرحمن لما قدمته من مساعدة في هذا البحث و يتصل الشكر ألساتذتي محكمي‬
‫االستبانة‪ .‬واخص بالشكر والتقدير شركة ليدر تكنوبالست التي ساهمت بكل ما كنا نحتاجه من مواْ و تصنيع‪.‬‬
‫‪2‬‬
:‫الخالصة‬
‫يتعلق المشروع بالمراسي العائمة تصميمها وتصنيعها والمواد المستخدمة فيها وتتمثل مهمة المشروع في ايجاد‬
‫مادة جديدة تمتلك خواص معينة واستخدامها في تصنيع المراسي العائمة بدال عن المواد المستخدمة حاليا في‬
.‫االسواق‬
‫وبنجاح‬.‫تم اختيار المادة المالئمة بعد دراسة مستفيضة وتم تصنيعها واختبارها في ظروف التشغيل واثبتت نجاحها‬
‫هذه المادة المستح دثة يمكن احداث طفرة في صناعة المراسي العائمة واستبدال المواد القديمة مثل الحديد بالمادة‬
.‫الجديدة‬
Abstract:
This research is about floating docks its designing, manufacturing and
materials used in it. And the objective of the research is to select a new
material possesses unique properties and use it in manufacturing docks
instead of the available materials in market.
The suitable material is selected after massive study and it is manufactured
and tested under operating conditions and it is succeeded. And thus
manufactured of floating docks could be developed and replace the old
materials as iron with the new one.
3
Table of Contents:
1.Chapter one----------------------------------------------------------------------------------5
1.1 Background-------------------------------------------------------------------------------6
1.2 Goals and Objectives-------------------------------------------------------------------6
1.3 Methodology------------------------------------------------------------------------------6
1.4 Expected Results------------------------------------------------------------------------6
1.5 Study Restrictions-----------------------------------------------------------------------6
2.Chapter Two---------------------------------------------------------------------------------8
2.1 Literature Review------------------------------------------------------------------------8
2.2 Types of Docks--------------------------------------------------------------------------14
2.3 Types of floating Docks---------------------------------------------------------------22
2.4 Boats---------------------------------------------------------------------------------------23
3.Chapter Three------------------------------------------------------------------------------30
3.1 Designing and Manufacturing--------------------------------------------------------30
3.2 Archimedes Principle-------------------------------------------------------------------42
3.3Designing the model and model dimensions--------------------------------------44
3.4Calculations--------------------------------------------------------------------------------45
3.5 Feasibility Study--------------------------------------------------------------------------48
4.Chapter Four--------------------------------------------------------------------------------49
4.1 Recommendations and Considerations--------------------------------------------49
4.2 Conclusion--------------------------------------------------------------------------------50
4.3 References--------------------------------------------------------------------------------51
4
Chapter One:
1.1)
background:
-Floating Docks
A large boxlike structure that can be submerged to allow a vessel to enter it
and then floated to raise the vessel out of the water for maintenance or repair
Also called floating dry dock.
A floating dock, floating pier or floating jetty is a platform or ramp supported by
pontoons. It is usually joined to the shore with a gangway. The pier is usually
held in place by vertical poles referred to as pilings, which are embedded in the
seafloor or by anchored cables.
Floating docks are important equipment which aid small naval vessels and
boats in the purpose of docking. Floating docks are simple and flexible in their
construction and build, which aids to the purpose of docking of small sea going
vessels extremely well.
Another important point to be noted about floating docks is that they are
feasible where the level of water is concerned in the sense that, floating docks
can be altered to push in more quantities of water for the boat docked or vice
versa, if the situation demands.
It is also important that floating docks are duly recorded as being a part of the
naval docks because floating docks do have the potential to harm the marine
world. And since the preservation of the marine world is a very important duty
and responsibility of the people manning the docks, it becomes necessary to
understand the relevance and practicality of registering a floating dock with the
right department.
One more important thing that needs to be mentioned about floating docks is
that they are available in different materials like aluminum, logs or lumber, steel
– both stainless as well as galvanized and Styrofoam, making it easy on the
part of the constructing team to choose the best possible material on the basis
of location and area where the floating docks are supposed to be built and setup.
Another major factor that needs to be monitored when it comes to floating docks
is the point about the marine world. As it is so happens, in today’s times, the
marine world is regarded to be one which is facing a lot of threat from the highly
5
developed and developing human world. With the use of equipment like the
floating docks which have the ease to alter the water level in the area where it
is placed, the marine world and the organisms inhabiting it face a lot of problems
and complications.
1.2) Goals and Objectives:
The objective of this research is to determine a material with specific
proprieties that can be utilized as a reliable material as it can carry heavy
loads in different conditions, has a relatively light weight compared to its
capacity, possess long lifetime “low deterioration over time”, and also
easy to maintain and replace and it must not get rusty and resist
corrosion.
1.3) Methodology:
1-Searching and surveying in markets to work out general view and to
obtain the basics equations used and the steps of manufacturing.
2-A model should be manufactured from the results of the design.
6-Model should be tested under working conditions to finally obtain if
the material is accepted or not accepted or float or not flaot.
1.4) Expected Results:
A new material will be used based on a design of floating objects which
can be utilized and used for boats or floating docks.
1.5) Study Restrictions:
-Lack of information because there is no previous studies and researches or
similar process in Sudan.
-The biggest concern and restriction is the financial aspect of manufacturing,
the market is so expensive.
-some places consider information as confidential.
6
Chapter one Illustrates background about floating docks, the goals and
objectives of the project and the methodology used from the beginning of the
project till the last result achieved beside the restrictions that obstacle the study.
While Chapter two includes general literature view about floating docks and
previous studies done in this field and also their types and the different
materials used in manufacturing docks in addition to boats manufacturing.
In the other object chapter three figured out the procedures of designing and
model manufacturing and feasibility study and testing of the manufactured
model.
Chapter contains conclusion and recommendations based on the whole work
and study of the project.
7
Chapter Two
Literature Review
The earliest known docks were those discovered in Wade al-Jarf, an ancient
Egyptian harbor dating from 2500 BCE located on the Red Sea coast.
Archaeologists also discovered anchors and storage jars near the site. A dock
from Lothal in India dates from 2400 BCE and was located away from the main
current to avoid deposition of silt. Modern oceanographers have observed that
the Harappans must have possessed great knowledge relating to tides in order
to build such a dock on the ever-shifting course of the Sabarmati, as well as
exemplary hydrography and maritime engineering. This was the earliest known
dock found in the world, equipped to berth and service ships.
In the modern history The first concept of the floating dock dates back to 1873
when two men, John Stanfield and Edwin Clark, formed a business called
Clark-Stanfield. They developed the first floating dock, its main purpose being
to raise large ships out of the water to be repaired. Their company remains the
leader in the development of docks, both standing and floating, and in 1973,
the company released the first set of guidelines in regard to the rules,
regulations
and
classification
of
the
building
of
floating
docks
In china The use of dry docks in China goes at least as far back the 10th century
A.D.In 1088, Song Dynasty scientist and statesman Shen Kuo (1031–1095)
wrote in his Dream Pool Essays:
At the beginning of the dynasty (c. +965) the two Che provinces (now Chekiang
and southern Chiangsu) presented (to the throne) two dragon ships each more
than 200 ft. in length. The upper works included several decks with palatial
cabins and saloons, containing thrones and couches all ready for imperial tours
of inspection. After many years, their hulls decayed and needed repairs, but the
work was impossible as long as they were afloat. So in the Hsi-Ning reign period
(+1068 to +1077) a palace official Huang Huai-Hsin suggested a plan. A large
basin was excavated at the north end of the Chin-ming Lake capable of
8
containing the dragon ships, and in it heavy crosswise beams were laid down
upon a foundation of pillars. Then (a breach was made) so that the basin quickly
filled with water, after which the ships were towed in above the beams. The
(breach now being closed) the water was pumped out by wheels so that the
ships rested quite in the air. When the repairs were complete, the water was let
in again, so that the ships were afloat once more (and could leave the dock).
Finally the beams and pillars were taken away, and the whole basin covered
over with a great roof so as to form a hangar in which the ships could be
protected from the elements and avoid the damage caused by undue exposure.
The first European and oldest surviving dry dock still in use was commissioned
by Henry VII of England at HMNB Portsmouth in 1495 (see Tudor navy). This
dry dock currently holds the world's oldest commissioned warship, HMS
Victory.
Possibly the earliest description of a floating dock comes from a small Italian
book printed in Venice in 1560, called Descrittione dell'artifitiosa machina. In
the booklet, an unknown author asks for the privilege of using a new method
for the salvaging of a grounded ship and then proceeds to describe and
illustrate his approach. The included woodcut shows a ship flanked by two large
floating trestles, forming a roof above the vessel. The ship is pulled in an upright
position by a number of ropes attached to the superstructure.
Modern times:
Liverpool (Old Dock)
In 1715 the first commercial wet dock, Liverpool's Old Dock, opened.[2] These
early docks were of simple construction: a single lock gate isolated them from
the tidal waters. Access was gained for a few hours around high tide by opening
this gate. Although this short opening period was disruptive to shipping, any
longer opening allowed the internal dock level to fall with the ebbing tide.
A half tide dock is a partially tidal dock. They need have no gate, but as the
tide ebbs a raised sill or weir on the floor of the dock prevents the level dropping
below a certain point, meaning that the ships in the dock remain afloat, although
9
they still fall with the first ebb of the tide. Half tide docks were only useful for
ships of shallow draught, in areas with a large tidal range. The tide must rise
sufficiently to give them a clear passage over the raised sill.
Hull
In 1775 Hull's Old Dock was opened. This was the first commercial floating
dock, isolated by a lock rather than a single lock gate. This allowed the dock's
water level to be maintained and, more importantly, it increased the time for
which tidal access was possible. However the lock was only 121 ft long and this
limited the number of ships passing through it.
Bristol
One of the first large fully floating docks was that of Bristol's Floating Harbour,
built in 1809 to a plan by William Jessop. This involved the diversion of the River
Avon (Bristol)away from its previous route through the harbour and into a new
channel at the New Cut. Entrance to the harbour was now gained through an
entrance basin, at what is now Cumberland Basin. Although linked by locks to
the harbour and the river, the intention was that the basin would itself be used
as an entrance lock: rather than locking each ship through one-by-one, ships
could wait for the tide inside the basin and then the outer lock gates could both
be opened allowing all to leave and arrive together. For a port with such a
convoluted and tide-dependent approach as Bristol's, any easing of access was
valuable.
As the harbour now need never be connected directly to the tidal waters, its
water level could be held constant, without even the small variation of the hours
around high tide. At Bristol, Jessop controlled the height of the harbour water
by a broad weir, built as a dam across the previous route of the river. Levels
were maintained by the flow of the small River Frome which still flowed into the
harbour.
The Alfredo da Silva Dry Dock, of the Lisnave Dockyards in Almada, Portugal,
was the largest in the world until 2000, when it was closed after the moving of
Lisnave operations to Setúbal.
10
Currently, Harland and Wolff Heavy Industries in Belfast, Northern Ireland, is
the site of the largest dry dock in the world. The massive cranes are named
after the Biblical figures Samson and Goliath. Goliath stands 96m tall, while
Samson is taller at 106m.
Dry Dock 12 at Newport News Shipbuilding is the largest dry dock in the
Western Hemisphere.[5] The Saint-Nazaire's Chantiers de l'Atlantique owns
one of the biggest in the world: 1,200 by 60 metres (3,940 ft × 200 ft). The
largest graving dock of the Mediterranean as of 2009 is at the Hellenic
Shipyards S.A. (HSY S.A., Athens, Greece)[1]. The by far largest roofed dry
dock is at the German Meyer Werft Shipyard in Papenburg, Germany, it is 504m
long, 125m wide and stands 75m tall.[6] —The largest dry dock in North
America named The Vigorous. It is operated Vigor Industries in Portland, OR,
in the Swan Island industrial area along the Willamette River.
The floating dry dock ‘Bermuda’ celebrates 143 years of arrival in Bermuda
today.
The ‘Bermuda’ was built in 1866 in North Woolwich, England, and arrived on
Bermuda’s shores in 1869. It was a patented invention of Messrs Campbell
Johnstone and Co. It weighed 8,200 tonnes and could lift any vessel afloat at
the time except for the Great Eastern, which was a large iron sailing steam ship.
It was the largest floating dock ever constructed and only lost that distinction to
its successor in 1901, Admiralty Floating Dock , also made for the Bermuda
Dockyard.
In her prime, the ‘Bermuda’ was used to accommodate large warships. The
Bermuda was more than 47,000 sq ft and 381ft long and 123ft at its maximum
width, and a depth of 74ft. It could easily accommodate ships up to 370ft long
and 25ft wide.
It went on to serve the Royal Navy until 1906. After partially dismantling the
dock, it was towed away from its post in Dockyard. During the towing process,
it was caught in a gale and drifted over to Spanish Point, where it got lodged on
the rocks and became unmovable. In 1950, the Bermuda Government tried to
clear the bay of the remnants of the dock using dynamite, to no avail. The now
11
rusted and ruined floating dock is located at the entrance to Stoves Bay, also
known as Pontoons in Spanish Point.
Fig (1): shows Bermuda dock
The first modern concept of the floating dock dates back to 1873 when two men,
John Stanfield and Edwin Clark, formed a business called Clark-Stanfield. They
developed the first modern floating dock, its main purpose being to raise large
ships out of the water to be repaired. Their company remains the leader in the
development of docks, both standing and floating, and in 1973, the company
released the first set of guidelines in regard to the rules, regulations and
classification
of
the
building
of
floating
docks.
The fleet of floating drydocks built by the Bureau of Yards and Docks during
World War II was a significant and at times dramatic factor in the Navy's
success in waging global war.
It had long been recognized that in the event of another world war the fleet
would be required to operate in remote waters, and that ships were going to
suffer hard usage and serious battle damage. It was obvious that many crippled
ships would be lost, or at least would be out of action for months while returning
to home ports for repairs, unless mobile floating drydocks could be provided
that could trail the fleet wherever it went. It was the Bureau's responsibility to
meet these requirements.
Floating drydocks have been used for overhaul and repair of ships for many
years, and many ingenious designs have been devised from time to time. One
of the most interesting was the Adamson dock, patented in 1816, which may
12
be considered the prototype of some of the new mobile docks. The Navy
apparently built several wooden sectional docks at various navy yards about
1850, but little is known of their history.
About 1900, two new steel floating drydocks were built for the Navy. The first
of these, of 18,000 tons lifting capacity, was built in 1899-1902 at Sparrow's
Point, Md., and towed to the Naval Station a Algiers, La., where it was kept in
intermittent service for many years. In 1940, it was towed via the Panama Canal
to Pearl Harbor to supplement the inadequate docking facilities there. Since the
dock was wider than the Canal locks, it was necessary to disassemble it at
Cristobal and to reassemble it at Balboa. Although both the dock and the ship
in it were damaged during the Japanese attack on Pearl Harbor on December
7, 1941, the dock was not lost, but was quickly repaired and subsequently
performed invaluable service both in the salvaging of vessels damaged in that
attack and in the support of the fleet in the Pacific.
The other dock, the Dewey, was a 16,000-ton dock, built in three sections, and
capable of docking itself. It was constructed in 1903-1905, also at Sparrow's
Point, Md., and was towed via the Suez Canal to the Philippines. The saga of
this voyage is an epic of ocean towing history. The Dewey was still in service
at Olongapo when the Japanese invaded the Philippines early in 1942. [sic:
Preliminary landings took place as early as 8 December, with the main landings
following on the 21st. Manila was occupied on New Years Day. -- HyperWar] It
was scuttled by the American naval forces before they abandoned the station.
Neither of these docks was suitable for mobile operation. Between 1920 and
1930, the Bureau of Yards and Docks made numerous studies of various types
of mobile docks of both unit and sectional types. In 1933, funds were finally
obtained for one 2,200-ton dock, and the Bureau designed and built the ARD1. This dock was of revolutionary design. It was a one-piece dock, ship-shaped
in form, with a molded closed bow and a faired stern, and may be best
described as U-shaped in both plan and cross-section. The stern was closed
by a bottom-hinged flap gate, operated by hydraulic rams. This gate was
lowered to permit entrance of a ship into the submerged dock and then closed.
The dock was then raised by pumping water from the ballast compartments and
13
also from the main basin. This dock was equipped with its own diesel-electric
power plant, pumping plant, repair shops, and crew's accommodations. It was
the first drydock in any navy which was sufficiently self-sustaining to
accompany a fleet into remote waters.
The ARD-1 was towed to Pearl Harbor, where it was used successfully
throughout the war. Thirty docks of this type, somewhat larger and incorporating
many improvements adopted as a result of operational experience with this
experimental dock, were constructed and deployed throughout the world during
the war. In 1935, the Bureau obtained $10,000,000 for a similar one-piece
mobile dock, to be capable of lifting any naval vessel afloat. Complete plans
and specifications were prepared by the Bureau for this dock, which was to be
1,027 feet long, 165 feet beam, and 75 feet molded depth. Bids received for
this huge drydock, designed as the ARD-3, appreciably exceeded the
appropriation, and the project was abandoned when the additional funds
needed for its execution were refused.
Fig (2) shows using docks in navy
2.2) Types of docks:
14
REMOVABLE DOCKS:
1-Floating Docks
Floating docks are relatively easy and economical to build, adaptable to most
shorelines and, because they are held up by the water, the distance between
the top of the dock’s deck and the surface of the water - known as freeboard remains fairly constant, varying only with dock load and high seas (being
minimal on a well-designed and well-built floater). Since a floating dock is not
dependent on submerged lands to hold it up, the added benefit is that there is
no maximum water depth that prevents its use.
From an environmental perspective, floating docks cause minimal direct
disruption to submerged lands; disruption typically caused by anchors, spuds,
or pilings (the most popular ways to moor a floating dock in place). In fact, if
secured to the shore only, there may be no contact with submerged lands at
all. However, floating docks can block sunlight to aquatic plants - altering fish
habitat - and they may also cause the erosion of shorelines. This means that
floating docks will not work everywhere. To minimize damage to the shoreline,
a floating dock must have sufficient buoyancy to keep its floats resting on water,
rather than bumping into submerged lands (which can harm both the dock and
aquatic habitat). A depth of 1 metre (approximately 3.3 feet) (measured at the
low-water mark) is the normal accepted minimum however, less depth may be
possible if the water level never varies and the area is not subject to harsh wave
action.
Floating docks often lack stability but it is not impossible to make a stable floater
- hundreds of good designs exist; some so stable a user could mistake the dock
underfoot for a waterfront boardwalk. Unfortunately, the number of unstable
disasters out there is great due to poor construction practices. When it comes
to stability, a floating dock works best when it is made long, wide, low, and
heavy. Remember to look for a design that will achieve this stability without
causing harm to fish habitat.
The consensus among dock builders is that 1.8 meters (approximately 6 feet)
x 6.1 meters (approximately 20 feet) is the minimum size for a stable floater;
15
this single section weighing in at about 450 kilograms (approximately 1000 lbs)
minimum. And bigger is even better for stability.
As usual, the drawbacks to bigger are increased initial cost, increased labour
for installation (and removal) and of course, greater impact on the shoreline’s
ecosystem. A pipe dock - which can be made smaller and still remain stable may be a preferable choice in shallow water.
In areas where ice conditions prohibit a four-season solution, the floating dock
offers the advantage that it can be removed from the water in the fall and
replaced in the spring (albeit with no small effort in some cases). That said,
many floaters are left in all year where wave action and ice conditions permit.
In addition to size and shape, float type and float location also contribute to
stability. A discussion of float types is beyond the scope of this booklet but as
a general rule, installing floats towards the perimeter of the dock, rather than
set back towards the dock’s centre line, greatly enhances stability.
Fig (3) shows a floating dry dock.
2-Pipe Docks
If you can imagine a 1 metre wide wooden ramp sitting about a quarter of a
metre above the water, supported by long skinny legs running from the ramp
down to submerged land, you have just mentally built a pipe dock. Building one
in reality is only a little more difficult, and not a lot more expensive (pipe docks
are typically the least costly dock option). As most of the dock sits out of water,
16
contact with the land and shading of aquatic vegetation is typically held to a
minimum, making a simple pipe dock the least disruptive to the environment of
all the dock types.
Unlike the floating dock, the pipe dock is stationary, therefore, the distance
between the dock and the water varies as the water rises and falls. Should the
lake or river at your shoreline do a gentle retreat through the season, the pipe
dock’s deck can usually be lowered on its legs to accommodate moderate
fluctuations in water levels, and even more extreme fluctuations can sometimes
be handled by relocating the dock further out on the shoreline. (The dock’s light
weight is a real advantage here). Some pipe dock legs can also be fitted with
wheels to make moving the dock an even easier task. Be aware that the
slightest amount of ice movement can fold up a pipe dock like an accordion, so
plan on moving the dock at least twice a year (the more favourable option), or
on buying a new one each spring.
Because a pipe dock’s deck and framing remain elevated above the water,
there is very little surface area exposed at the waterline for nature to damage.
This makes the pipe dock a good candidate for situations where plenty of
surface activity is experienced, such as on busy river channels where the wakes
from passing boats may be a problem. However, with waves passing under the
dock unobstructed, any boat moored to the opposite side will be exposed to the
full brunt of wave action.
Severe wave action can put some of the lighter aluminum pipe docks at risk.
However, lighter construction also means less labour to install and remove the
dock, and less initial cost to purchase. And in the right situation - a protected
bay for instance - a lightweight pipe dock is certainly up to the task of mooring
smaller boats. For larger vessels and harsher wave action, boat lifts or marine
railways are a better choice.
Because a pipe dock is propped up on legs, it can be built smaller than a
floating dock yet still remain stable. The basic rule for pipe docks is that the
width of the dock should be at least 1 metre (approximately 3.3 feet) and never
less than the depth of the water. Because stability suffers as legs get longer,
17
about 2 metres (6-7 feet) is considered the maximum water depth for pipe dock
installations. Choose one of the other dock types - such as a floating dock - for
deeper water.
Because they have little contact with submerged lands, pipe docks are easy on
the aquatic environment.
Fig (4) shows a pipe dock
PERMANENT DOCKS:
1-Graving docks
The classic form of dry dock, properly known as a graving dock, is a narrow
basin, usually made of earthen berms and concrete, closed by gates or a
caisson, into which a vessel may be floated and the water pumped out, leaving
the vessel supported on blocks as shown in figure (5). The keel blocks as well
as the bilge block are placed on the floor of the dock in accordance with the
"docking plan" of the ship.
Some fine-tuning of the ship's position can be done by divers while there is still
some water left to maneuver it about. It is extremely important that supporting
blocks conform to the structural members so that the ship is not damaged when
its weight is supported by the blocks. Some anti-submarine warfare warships
have protruding sonar domes, requiring that the hull of the ship be supported
several meters from the bottom of the dry dock.
18
Once the remainder of the water is pumped out, the ship can be freely inspected
or serviced. When work on the ship is finished, water is allowed to re-enter the
dry dock and the ship is carefully refloated.
Modern graving docks are box-shaped, to accommodate the newer, boxier ship
designs, whereas old dry docks are often shaped like the ships that are
intended to be docked there. This shaping was advantageous because such a
dock was easier to build, it was easier to side-support the ships, and less water
had to be pumped away.
Dry docks used for building Navy vessels may occasionally be built with a roof.
This is done to prevent spy satellites from taking pictures of the dry dock and
any ships or submarines that may be in it. During World War II, covered dry
docks were frequently used by submarine fleets to protect them from enemy air
raids, however their effectiveness in that role diminished after that war. Today,
covered dry docks are usually used only when servicing or repairing a fleet
ballistic missile submarine. Another advantage of covered dry docks is that one
can work independently of the weather. This can save time in bad weather.
Fig (5) shows a graving dock
2-Crib Docks
19
A “crib” is a container. In the context of waterfront construction, a crib holds a
few tons of rock and stone. Cribs should not be confused with gabions. Gabions
are inexpensive wire or plastic mesh baskets designed to hold stones, rock, or
concrete; the baskets wired together to serve as unattractive retaining walls. At
first glance, they may seem like a good idea for dock building, but time has
proven gabions to be better at tearing skin than retaining rock under siege by
strong currents, waves, and ice, all of which will distort the basket’s shape,
causing the gabion to sag and flatten.
A proper crib is built from new, square-cut timber, not wire or driftwood or round
logs tacked together with small nails and hope. (Occasionally, steel or concrete
castings are used in lieu of wood). The timbers are assembled in opposing
pairs, one pair laid out on top of the next, creating a slatted, box-like affair with
an integral floor. Threaded rods run the full height in each corner to secure the
timbers in place. The box is then filled with rock.
Maximum water depth for a crib is about 2.5 metres (approximately 8 feet). For
optimum stability, a crib’s total height should at least equal its total width.
Obviously, this can make for a very large container, which in turn needs a ton
or more of rock to fill it, and all of this rock must be taken from onshore sources,
not from close-at-hand submerged lands (which would disrupt fish habitat). For
this reason, and from an environmental standpoint, cribs should be placed
above the ordinary high water mark, using the strength of the crib as an anchor
or attachment point for other structures such as floating docks, cantilever docks
or pipe docks. (On a lakeshore, the ordinary high water mark is the highest point
to which water customarily rises, and where the vegetation changes from
mostly aquatic species to terrestrial). If however, cribs must be placed in the
water, leave at least 2 metres (6-7 feet) between them, and locate them at least
2 metres from the ordinary high water mark. This will allow near-shore water to
circulate around the structures.
From an environmental perspective, floating and pipe docks are preferred to
crib docks, since crib docks can cover over sensitive spawning habitat and
result in the removal of rocks and logs that provide shelter.
20
2.3) Types of Floating Docks
There are many types of floating docks available and generally they classified
according to the material used to build the dock. There is the wooden dock,
which is
the least expensive type to build because of its use of simple materials. Another
type is the Floating Polydock. This type of dock is easy to install and uses a
connection system. This means that the pieces can be connected in any shape
that is desired and can be easily rearranged. It goes by a modular design, which
allows for the expansion of the dock if something larger is required. There is
also the Galva Foam Steel dock. This type of dock usually incorporates the use
of galvanized steel, making for a more durable construction. It offers more
stable ramps for safety and uses a higher density polyethylene, meaning that
there is greater strength for floatation.
Fig (6) wooden floating dock
21
Fig (7) poly floating dock
2.4) Reasons of Using Floating Docks
Floating docks provide much more stability than fixed pier docks. They are
engineered to provide greater buoyancy and to distribute weight more evenly
than fixed docks. Because they float, the vertical distances remain the same,
allowing boats and passengers to easily enter and exit boats without climbing
down in low water levels. In high water conditions, the docks still remain at the
same fixed height. If water levels are very low, creating a wider shoreline, the
ramps to the floating docks can be extended, allowing the dock to float in deeper
water while maintaining access from the shore. Maintenance is low and
components can last for years without replacement due to wear. Floating docks
can also be moved, if necessary, and can be constructed with open or covered
slips.
Floating dock systems are modular. Additional slips can be added for expansion
of growing marinas.
2.5) Boats:
A boat is a watercraft designed to float on and provide transport over water. It
is usually operated on inland bodies of water (such as lakes or rivers) shown in
figure (8) below or in protected coastal areas. However, some boats, such as
the whaleboat, were historically designed to be operated from a ship in an
offshore environment.
In naval terms, a boat is small enough to be carried aboard another vessel (a
ship). Notable exceptions to this size concept are the Great Lakes freighter,
riverboat, narrowboat, and ferryboat. These are examples of large boats, but
they generally operate on inland and protected coastal waters. Modern
submarines may also be referred to as boats (despite their underwater
capabilities and size), perhaps because early submarines could be carried by
a ship and were not capable of making offshore passages on their own. Boats
may have military, other government, research, or commercial usage; but a
22
vessel, regardless of size, that is in private, non-commercial usage is almost
always called a boat.
Boats of various types have been built and used since ancient history, allowing
people to transport themselves and their cargo across large stretches of water
without having to swim. In addition, they have been used for fishing. Large ships
are usually equipped with small lifeboats that can be used for emergency
evacuation of the passengers and crew. Also, in places where large ships
cannot venture too close to the shore, small boats are used to shuttle people
and their belongings between ship and shore.
2.6) Reasons that make boats floats
A boat stays afloat because its weight is equal to that of the water it displaces.
The material of the boat itself may be heavier than water (per volume), but it
forms only the outer layer. Inside the boat is air, which is negligible in weight,
but the air adds to the volume. The central term here is density, which is mass
('weight') per unit volume. The mass of the boat (including its contents) as a
whole has to be divided by the volume below the waterline. If that figure is equal
to the density of water (roughly one kilogram per liter), the boat will float. If
weight is added to the boat, the volume below the waterline will have to increase
too, to maintain the same average density. Consequently, the boat sinks a little
to compensate.
Figure (8) shows a floating boat
23
2.7) Parts of Boats:
The front of a boat is called the bow or prow. The rear of the boat is called the
stern. The right side is starboard and the left side is port. On old time boats, a
Figurehead sits on the front of the bow.
The roughly horizontal, but cambered structures spanning the hull of the boat
are referred to as the "deck." A ship often has several decks, but a boat is
unlikely to have more than one. The similar but usually lighter structure that
spans a raised cabin is a "coach-roof." The underside of a deck is the deck
head.
The "floor" of a cabin is properly known as the sole, but it is more likely to be
called the floor. (In proper terms, a floor is a structure that ties a frame to the
keelson and keel.) The keel is a lengthwise structural member to which the
frames are fixed (sometimes referred to as a backbone). The vertical surfaces
dividing the internal space are bulkheads.
Until the mid-nineteenth century, most boats were made of all-natural materials,
primarily wood. Many boats had been built with iron or steel frames but were
still planked in wood. In 1855, ferro-cement boat construction was patented by
the French. They called it Ferciment. This is a system by which a steel or iron
wire framework is built in the shape of a boat's hull and covered (troweled) over
with cement. Reinforced with bulkheads and other internal structure, it is strong
but heavy, easily repaired, and, if sealed properly, will not leak or corrode.
These materials and methods were copied all over the world, and have faded
in and out of popularity to the present.
As the forests of Britain and Europe continued to be over-harvested to supply
the keels of larger wooden boats, and the Bessemer Process (patented in 1855)
cheapened the cost of steel, steel ships and boats began to be more common.
By the 1930s, boats built of all steel from frames to plating were seen replacing
wooden boats in many industrial uses, even the fishing fleets. Private
recreational boats in steel are uncommon. In the mid-twentieth century,
aluminum gained popularity. Though much more expensive than steel, there
are now aluminum alloys available that will not corrode in salt water, and an
24
aluminum boat built to similar load carrying standards could be built lighter than
steel. The boat-building industry is now being dominated by fiberglass.
Platt Monfort invented Wire Plank(r)(1969), Fer-a-Lite(r)(1972), Str-r-etch
Mesh(r)(1975), and Geodesic Airolite Boats(r)(1981). Fer-A-Lite(r) is a mixture
of polyester resin, fiberglass, and a filler. This, along with Str-r-etch Mesh(r),
could be used to build a boat in the same fashion as a ferro-cement boat, but
the resulting hull would be much lighter and more resilient. Wire Plank(r) was
first used in ferro-cement construction, but could also be used with Fer-a-Lite
to create a medium to heavy weight hull. Geodesic Airolite Boats(r) are built
using very lightweight wooden frames (geodesic) that are covered over with
some lightweight heatshrinkable plastic or a synthetic fabric such as dacron
coated with sealant. This tensioned skin adds to the overall strength of the
structure and boats built thus are of the ultra-light variety. Boats come in many
different shapes and sizes, so that some boats will be used perfectly against
different types of waves.
Around the mid-1960s, boats made out of glass-reinforced plastic, more
commonly known as fiberglass, became popular, especially for recreational
boats. The coast guard refers to such boats as 'FRP' (for Fiberglass Reinforced
Plastic) boats. Fiberglass boats are extremely strong, and do not rust, corrode,
or rot. They are, however, susceptible to structural degradation from sunlight
and extremes in temperature over their lifespan. Fiberglass provides structural
strength, especially when long woven strands are laid, sometimes from bow to
stern, and then soaked in epoxy or polyester resin to form the hull of the boat.
Whether hand laid or built in a mold, FRP boats usually have an outer coating
of gelcoat which is a thin solid colored layer of polyester resin that adds no
structural strength, but does create a smooth surface which can be buffed to a
high shine. One of the disadvantages of fiberglass is that it is heavy and to
alleviate this, various lighter components can be incorporated into the design.
One of the more common methods is to use cored FRP, with the core being
balsa wood completely encased in fiberglass. Cored FRP is most often found
in decking which helps keep down weight that will be carried above the
waterline. While this works, the addition of wood makes the cored structure of
25
the boat susceptible to rotting. The phrase 'advanced composites' in FRP
construction may indicate the addition of carbon fiber, kevlar(tm) or other similar
materials, but it may also indicate other methods designed to introduce less
expensive and, by at least one yacht surveyor's eyewitness accounts, less
structurally sound materials.
Cold molding is similar to FRP in as much as it involves the use of epoxy or
polyester resins, but the structural component is wood instead of fiberglass. In
cold molding very thin strips of wood are laid over a form or mold in layers. This
layer is then coated with resin and another directionally alternating layer is laid
on top. In some processes the subsequent layers are stapled or otherwise
mechanically fastened to the previous layers, but in other processes the layers
are weighted or even vacuum bagged to hold layers together while the resin
sets. Layers are built up thus to create the required thickness of hull.
People have even made their own boats or watercraft out of commonly
available materials such as styrofoam or plastic, but most homebuilts today are
built of plywood and either painted or covered in a layer of fiberglass and resin.
2.8) Boat propulsion
The most common means of propulsion are:
Human power (rowing, paddling, setting pole, and so forth)
Wind power (sailing)
Motor powered screws
Inboard
Internal Combustion (gasoline, diesel)
Steam (Coal, fuel oil)
Nuclear (for large boats)
Inboard/Outboard
26
Gasoline
Diesel
Outboard
Gasoline
Electric
Paddle Wheel
Water Jet (Jet ski, Personal water craft, Jetboat)
Air Fans (Hovercraft, Air boat)
2.9) Types of boats:
There are many and various types of boats and here is a list for common boats
wide word:

Air boat

Banana
boat

Bangca

Bareboat
charter

Barge

Bellyboat

Bow Rider

Cabin
cruiser

Canoe

Cape
Islander

Car-boat

Dredge

Drift Boat

Durham

Lifeboat
Boat

Log boat
Express

Longboat
Cruiser

Longtail

Felucca

Luxury

Ferry

Fireboat

Motorboat

Fishing

Narrowboat
boat

Norfolk


Flyak

Folding

Landing
craft
yacht
wherry

boat
Outrigger
canoe
27

Schooner

Scow

Sharpie

Shikaras

Ship's
tender

Ski boat

Skiff

steam boat

Slipper
Launch

Sloop

Submarine

Surf boat

Swift boat

Caravel



Catamaran

Catboat

Gondola

Coble

Great
water craft

Center
Lakes
(PWC)

Tugboat
Console
freighter

Pinnace

U-boat
Go-fast
boat

Padded V-

Tarai Bune
hull

Trimaran
Personal

Trawler
(fishing)

Coracle

Houseboat

Pirogue

Waka

Cruiser

Hovercraft

Pleasure

Wakeboard

Cruising

Hydrofoil
trawler

Hydroplane

Pontoon

Walkaround

Cuddy

Inflatable

Powerboat

Water taxi

Cutter
boat

Punt

Whaleboat
craft
boat
(sailing

Jetboat

Raft

Yacht
boat)

Jet ski

Rigid-hulled

Yawl

Dhow

Jon boat

Dinghy

Junk

Riverboat

Dory

Kayak and

Runabout

Dragon
Sea kayak

Rowboat,
boat

inflatable
Ketch
rowing boat

Sailboat,
sailing boat

Sampan
Unusual boats have been used for sports purposes. For example, "big bathtub
races" use boats made from bathtubs. Pumpkins have been used as boats as
in the annual Pumpkin Boat Race on Lake Otsego in New York state, USA. In
this race, very large, hollowed-out pumpkin shells are used for boats, powered
by canoe paddles.
28
Fig (9) shows air boat
29
Chapter Three:
Designing and manufacturing
Manufacturing of floating docks goes through several levels and
developments specially in materials used to manufacture the docks because
of great developing of materials science.
From the beginning of the floating docks manufacturing many materials are
used to build them such as steel, wood, plastic, and modern composite
materials.
Therefore in this chapter a suitable material must be specified according to
the requirements of the application and the application conditions.
1. Steel:
Steels are alloys of iron and other elements, primarily carbon, widely used in
construction and other applications because of their high tensile strengths and
low costs. Carbon, other elements, and inclusions within iron act as hardening
agents that prevent the movement of dislocations that otherwise occur in the
crystal lattices of iron atoms.
The carbon in typical steel alloys may contribute up to 2.1% of its weight.
Varying the amount of alloying elements, their formation in the steel either as
solute elements, or as precipitated phases, retards the movement of those
dislocations that make iron comparatively ductile and weak, and thus controls
qualities such as the hardness, ductility, and tensile strength of the resulting
steel. Steel's strength compared to pure iron is only possible at the expense of
ductility, of which iron has an excess.
The carbon content of steel is between 0.002% and 2.1% by weight for plain
iron-carbon alloys. These values vary depending on alloying elements such as
manganese, chromium, nickel, iron, tungsten, carbon and so on. Basically,
steel is an iron-carbon alloy that does not undergo eutectic reaction. In contrast,
cast iron does undergo eutectic reaction, suddenly solidifying into solid phases
30
at exactly the same temperature. Too little carbon content leaves (pure) iron
quite soft, ductile, and weak. Carbon contents higher than those of steel make
an alloy, commonly called pig iron, that is brittle (not malleable). While iron
alloyed with carbon is called carbon steel, alloy steel is steel to which other
alloying elements have been intentionally added to modify the characteristics
of steel. Common alloying elements include: manganese, nickel, chromium,
molybdenum, boron, titanium, vanadium, tungsten, cobalt, and niobium.
Additional elements are also important in steel: phosphorus, sulfur, silicon, and
traces of oxygen, nitrogen, and copper.
Alloys with a higher than 2.1% carbon content, depending on other element
content and possibly on processing, are known as cast iron. Cast iron is not
malleable even when hot, but it can be formed by casting as it has a lower
melting point than steel and good castability properties. Certain compositions
of cast iron, while retaining the economies of melting and casting, can be heat
treated after casting to make malleable iron or ductile iron objects. Steel is also
distinguishable from wrought iron (now largely obsolete), which may contain a
small amount of carbon but large amounts of slag.
History of steelmaking
Main articles: History of ferrous metallurgy, History of the steel industry (1850–
1970) and History of the steel industry (1970–present)
Bloomery smelting during the middle Ages
Ancient steel:
Steel was known in antiquity, and may have been produced by managing
bloomeries and crucibles, or iron-smelting facilities, in which they contained
carbon.
The earliest known production of steel are pieces of ironware excavated from
an archaeological site in Anatolia (Kaman-Kalehoyuk) and are nearly 4,000
31
years old, dating from 1800 BC.[17][18] Horace identifies steel weapons like
the falcata in the Iberian Peninsula, while Noric steel was used by the Roman
military.
The reputation of Seric iron of South India (wootz steel) amongst the Greeks,
Romans, Egyptians, East Africans, Chinese and the Middle East grew
considerably.[16] South Indian and Mediterranean sources including Alexander
the Great (3rd c. BC) recount the presentation and export to the Greeks of 100
talents of such steel. Metal production sites in Sri Lanka employed wind
furnaces driven by the monsoon winds, capable of producing high-carbon steel.
Large-scale Wootz steel production in Tamilakam using crucibles and carbon
sources such as the plant Avāram occurred by the sixth century BC, the
pioneering precursor to modern steel production and metallurgy.
Steel was produced in large quantities in Sparta around 650 BC.
The Chinese of the Warring States period (403–221 BC) had quench-hardened
steel, while Chinese of the Han dynasty (202 BC – 220 AD) created steel by
melting together wrought iron with cast iron, gaining an ultimate product of a
carbon-intermediate steel by the 1st century AD. The Haya people of East
Africa invented a type of furnace they used to make carbon steel at 1,802 °C
(3,276 °F) nearly 2,000 years ago. East African steel has been suggested by
Richard Hooker to date back to 1400 BC.
Wootz steel and Damascus steel
Evidence of the earliest production of high carbon steel in the Indian
Subcontinent are found in Kodumanal in Tamil Nadu area, Golconda in Andhra
Pradesh area and Karnataka, and in Samanalawewa areas of Sri Lanka. This
came to be known as Wootz steel, produced in South India by about sixth
century BC and exported globally. The steel technology existed prior to 326 BC
in the region as they are mentioned in literature of Sangam Tamil, Arabic and
Latin as the finest steel in the world exported to the Romans, Egyptian, Chinese
and Arabs worlds at that time - what they called Seric Iron. A 200 BC Tamil
trade guild in Tissamaharama, in the South East of Sri Lanka, brought with them
32
some of the oldest iron and steel artefacts and production processes to the
island from the classical period.The Chinese and locals in Anuradhapura, Sri
Lanka had also adopted the production methods of creating Wootz steel from
the Chera Dynasty Tamils of South India by the 5th century AD.In Sri Lanka,
this early steel-making method employed a unique wind furnace, driven by the
monsoon winds, capable of producing high-carbon steel.Since the technology
was acquired from the Tamilians from South India, the origin of steel technology
in India can be conservatively estimated at 400–500 BC.
Wootz, also known as Damascus steel, is famous for its durability and ability to
hold an edge. It was originally created from a number of different materials
including various trace elements, apparently ultimately from the writings of
Zosimos of Panopolis. However, the steel was an old technology in India when
King Porus presented a steel sword to the Emperor Alexander in It was
essentially a complicated alloy with iron as its main component. Recent studies
have suggested that carbon nanotubes were included in its structure, which
might explain some of its legendary qualities, though given the technology of
that time, such qualities were produced by chance rather than by design.
Natural wind was used where the soil containing iron was heated by the use of
wood. The ancient Sinhalese managed to extract a ton of steel for every 2 tons
of soil, a remarkable feat at the time. One such furnace was found in
Samanalawewa and archaeologists were able to produce steel as the ancients
did.
Crucible steel, formed by slowly heating and cooling pure iron and carbon
(typically in the form of charcoal) in a crucible, was produced in Merv by the 9th
to 10th century AD. In the 11th century, there is evidence of the production of
steel in Song China using two techniques: a "berganesque" method that
produced inferior, inhomogeneous, steel, and a precursor to the modern
Bessemer process that used partial decarbonization via repeated forging under
a cold blas
33
Advantages of steel:
The many advantages of steel can be summarized as follow:
1. High strength.
Can carry heavy loads.
2. Ductility
A very desirable of property of steel in which steel can withstand extensive
deformation without failure under high tensile stresses
3. Hardness
4.Durability
One of the most obvious advantages to using steel.
-Disadvantages of steel:
Though steel contains many advantages, there will always be a few
disadvantages along with it:
develop molding during the winter
Since steel also contain metal material, if not treated carefully it can be toxic to
the environment as well.
It may also have a tendency for corrosion and rust if not maintain correctly,
thus it might not be as cost effective due to constant maintenance.
It has heavy load which is not recommended.
2-Wood:
Wood is a porous and fibrous structural tissue found in the stems and
roots of trees and other woody plants.
34
an organic material, a natural composite of cellulose fibers (which are strong in
tension) embedded in a matrix of lignin which resists compression. Wood is
sometimes defined as only the secondary xylem in the stems of trees, or it is
defined more broadly to include the same type of tissue elsewhere such as in
the roots of trees or shrubs. In a living tree it performs a support function,
enabling woody plants to grow large or to stand up by themselves. It also
conveys water and nutrients between the leaves, other growing tissues, and
the roots. Wood may also refer to other plant materials with comparable
properties, and to material engineered from wood, or wood chips or fiber.
The Earth contains about one trillion tonnes of wood, which grows at a rate of
10 billion tonnes per year. As an abundant, carbon-neutral renewable resource,
woody materials have been of intense interest as a source of renewable energy.
In 1991, approximately 3.5 cubic kilometers of wood were harvested. Dominant
uses were for furniture and building construction.
Wood Advantages
Functional
Durable material. Due to the new technical treatment in the wood products, the
good qualities and properties of the products stay longer and just with a simply
maintenance, is possible to recover the initial properties.
Reusable, recycle and recoverable material. Timber is a renewable material
that comes directly from trees in sustainable forest management.
Due to the cellular structure, timber is and excellent thermal insulator,
avoiding sudden change of temperature, reducing the need of heating and
cooling.
Keep the hygroscopic balance with the environment, due to its porous structure.
Excellent acoustic insulator, due to the chemical composition in lignin and
cellulose that absorb an important energy of acoustic waves, with the reduction
of acoustic pollution and other phenomenon as reverberation.
35
Timber is bound with efficiency energetic. Timber products are really
competitive because the energy loss, mainly calorific, is very little compared
with other materials, due to its porous structure full of air that becomes timber
in the best thermal and acoustic insulator.
Apart from the energetic save that suppose the use of timber products, we have
to consider also the save that suppose the recycle of all the components when
end the product's useful service life.
Beneficial for health due to timber product give a subjective comfort.
Adaptability.
Short time to staging.
Structural stability.
Better resistance against fire than other materials due to the low thermal
conductivity.
Environmental Advantages
Wood is the only material that reducesthe CO2 emission, as play an important
role to slow down Climatic Change.
Timber
needs
less
energy
in
its
manufacturing
process,
so
has
an environmental impact lower than other materials in their life service cycle.
Wood is an important drain of CO2meanwhile the products keep their life
service cycle.
Wood is a natural resource, renewable, whose consume help the local
sustainable management of forests and environmental protection.
Sustainable forestall management, timber industry could continue it activity in
the future, also strengthen the sense of social and environmental responsibility.
36
Timber products make easier to carry out the commitments of the Kyoto
protocol.
-Disadvantages of wood:
*Shrinkage and Swelling of Wood:
Wood is a hygroscopic material. This means that it will adsorb surrounding
condensable vapors and loses moisture to air below the fiber saturation point.
*Deterioration of Wood:
The agents causing the deterioration and destruction of wood fall into two
categories: Biotic (biological) and abiotic (non-biological).
Biotic agents include decay and mold fungi, bacteria and insects.
Abiotic agents include sun, wind, water, certain chemicals and fire.
*could not carry heavy loads
*absorbs moisture
-Selecting the new material:
A new material is developed and selected and the reason of choosing this
material is that it has the advantage of light weight and could carry heavy loads
beside other more advantages.it is called HDPE
-High Density Polyethylene ”HDPE”It is a thermoplastic composite material.
High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a
polyethylene thermoplastic made from petroleum. It is sometimes called
"alkathene" or "polythene" when used for pipes.[1] With a high strength-todensity ratio, HDPE is used in the production of plastic bottles, corrosionresistant piping, geomembranes, and plastic lumber. HDPE is commonly
37
recycled, and has the number "2" as its resin identification code (formerly
known as recycling symbol).
Properties
HDPE is known for its large strength-to-density ratio. The density of HDPE can
range from 0.93 to 0.97 g/cm3 or 970 kg/m3. Although the density of HDPE is
only marginally higher than that of low-density polyethylene, HDPE has little
branching, giving it stronger intermolecular forces and tensile strength than
LDPE. The difference in strength exceeds the difference in density, giving
HDPE a higher specific strength. It is also harder and more opaque and can
withstand somewhat higher temperatures (120 °C/ 248 °F for short periods,
110 °C /230 °F continuously). High-density polyethylene, unlike polypropylene,
cannot withstand normally required autoclaving conditions. The lack of
branching is ensured by an appropriate choice of catalyst (e.g., Ziegler-Natta
catalysts) and reaction conditions.
Fig. (10)HDPE pipe installation in storm drain project in Mexico
38
HDPE is resistant to many different solvents and has a wide variety of
applications:
Swimming pool installation
3-D printer filament
Arena Board (puck board)
Backpacking frames
Ballistic plates
Banners
Bottle caps
Chemical-resistant piping
Coax cable inner insulator
Food storage containers
Fuel tanks for vehicles
Corrosion protection for steel pipelines
HDPE is also used for cell liners in subtitle D sanitary landfills, wherein large
sheets of HDPE are either extrusion or wedge welded to form a homogeneous
chemical-resistant barrier, with the intention of preventing the pollution of soil
and groundwater by the liquid constituents of solid waste.
HDPE is preferred by the pyrotechnics trade for mortars over steel or PVC
tubes, being more durable and safer. HDPE tends to rip or tear in a malfunction
instead of shattering and becoming shrapnel like the other materials.
Milk jugs and other hollow goods manufactured through blow molding are the
most important application area for HDPE, accounting for one-third of
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worldwide production, or more than 8 million tons. In addition to being recycled
using conventional processes, HDPE can also be processed by recyclebots
into filament for 3-D printers via distributed recycling. There is some evidence
that this form of recycling is less energy intensive than conventional recycling,
which can involve a large embodied energy for transportation.
Above all, China, where beverage bottles made from HDPE were first imported
in 2005, is a growing market for rigid HDPE packaging, as a result of its
improving standard of living. In India and other highly populated, emerging
nations, infrastructure expansion includes the deployment of pipes and cable
insulation made from HDPE.[2] The material has benefited from discussions
about possible health and environmental problems caused by PVC and
Polycarbonate associated Bisphenol A, as well as its advantages over glass,
metal, and cardboard.
-The HDPE industry in SudanHDPE is imported in a shape of grains raw material by leader technoplast
industry as shown in figure (11) below
Fig (11) HDPE Raw Material
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And then it goes through several operating machines to form and manufacture
it to the final shape as in figure (12)
Fig (12) HDPE Forming Machine
Fig (13) HDPE Pipes
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3.2) Calculations and Archimedes principle:
The base of calculations of this application depends on Archimedes principle
*Archimedes principle*
Archimedes' principle indicates that the upward buoyant force that is exerted
on a body immersed in a fluid, whether fully or partially submerged, is equal to
the weight of the fluid that the body displaces. Archimedes' principle is a law of
physics fundamental to fluid mechanics. Archimedes of Syracuse formulated
this principle, which bears his name.
Practically, the Archimedes principle allows the buoyancy of an object partially
or wholly immersed in a liquid to be calculated. The downward force on the
object is simply its weight. The upward, or buoyant, force on the object is that
stated by Archimedes' principle, above. Thus the net upward force on the object
is the difference between the buoyant force and its weight. If this net force is
positive, the object rises; if negative, the object sinks; and if zero, the object is
neutrally buoyant - that is, it remains in place without either rising or sinking. In
simple words, Archimedes' principle states that when a body is partially or
completely immersed in a fluid, it experiences an apparent loss in weight which
is equal to the weight of the fluid displaced by the immersed part of the body.
In other words, for an object floating on a liquid surface (like a boat) or floating
submerged in a fluid (like a submarine in water or dirigible in air) the weight of
the displaced liquid equals the weight of the object. Thus, only in the special
case of floating does the buoyant force acting on an object equal the objects
weight. Consider a 1-ton block of solid iron. As iron is nearly eight times denser
than water, it displaces only 1/8 ton of water when submerged, which is not
enough to keep it afloat. Suppose the same iron block is reshaped into a bowl.
It still weighs 1 ton, but when it is put in water, it displaces a greater volume of
water than when it was a block. The deeper the iron bowl is immersed, the more
water it displaces, and the greater the buoyant force acting on it. When the
buoyant force equals 1 ton, it will sink no farther.
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When any boat displaces a weight of water equal to its own weight, it floats.
This is often called the "principle of flotation": A floating object displaces a
weight of fluid equal to its own weight. Every ship, submarine, and dirigible must
be designed to displace a weight of fluid at least equal to its own weight. A
10,000-ton ship must be built wide enough to displace 10,000 tons of water
before it sinks too deep in the water. The same is true for vessels in air: a
dirigible that weighs 100 tons needs to displace 100 tons of air. If it displaces
more, it rises; if it displaces less, it falls. If the dirigible displaces exactly its
weight, it hovers at a constant altitude.
It is important to realize that, while they are related to it, the principle of floatation
and the concept that a submerged object displaces a volume of fluid equal to
its own volume are not Archimedes' principle. Archimedes' principle, as stated
above, equates the buoyant force to the weight of the fluid displaced.
One common point of confusion regarding Archimedes' principle is the meaning
of displaced volume. Common demonstrations involve measuring the rise in
water level when an object floats on the surface in order to calculate the
displaced water.This measurement approach fails with a buoyant submerged
object because the rise in the water level is directly related to the volume of the
object and not the mass (except if the effective density of the object equals
exactly the fluid density). Instead, in the case of submerged buoyant objects,
the whole volume of fluid directly above the sample should be considered as
the displaced volume. Another common point of confusion regarding
Archimedes' principle is that it only applies to submerged objects that are
buoyant, not sunk objects. In the case of a sunk object the mass of displaced
fluid is less than the mass of the object and the difference is associated with
the object's potential energy.
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Consider a uniform cylinder immersed in a liquid as shown in Figure (14)
below:
Force on the upper face of
the
cylinder
=
hρgA
Force on the lower face of
the cylinder = [h + L]ρgA
Difference in force = LρgA
But LA is the volume of liquid
displaced by the cylinder,
and LrgA is the weight of the
liquid
displaced
by
the
cylinder.
Therefore there is a net upward force on the cylinder equal to the weight of the
fluid
displaced
by
it.
The same result will be obtained for a body of any shape, regular or not by
taking into account the vertical and horirontal components of the forces on the
object.
3.3) Designing the model and model dimensions
Given informations:- Two pipes form (HDPE) closed from the two sides and has outer diameter
200 mm and inside diameter 190 mm and the length is one meter .
-Sheet steel with dimensions ( 1 × 1) with thickness 1 mm “as initial value”
- Six rings from steel with outer diameter 201 mm and inside diameter 200 mm
and length of 5 mm
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- Three pieces from steel support the sheet steel and prevent it from bending
and has a length of 1 meter and dimensions ( 5 cm × 3 cm ) with thickness 0.7
mm
- 11 screws with total mass 70 g .
- The density of the materials is:Water 1000 Kg/𝑚3
Steel 7700 Kg/𝑚3
HDPE 955 Kg/𝑚3
3.4) Calculations:1. Volumes and masses
First the Masses and volumes of the components must be determined
theoretically.
𝜋
Volume of one pipe = 4 ∗ ( 0.22 − 0.192 ) ∗ 1 = 3.063 ∗ 10−3 𝑚3
Mass of two pipes = 2* volume * density = 2*3.063 ∗ 10−3 ∗ 955 = 5.85 𝐾𝑔
Mass of sheet steel = volume * density = 1*1*0.001*7700 = 7.7 Kg
𝜋
Mass of rings = 6 * 4 ∗ ( 0.2012 − 0.22 ) ∗ 0.05 ∗ 7700 =0.728 Kg
Mass of 3 pipes of steel = ((0.05 ∗ 0.03) − (0.043 ∗ 0.023)) ∗ 1 ∗ 3 ∗ 7700 =
3.93 Kg
At the lab we found that masses are:
HDPE pipes is 5.91 Kg
Sheet steel is 7.82 Kg
Rings is 0.684 Kg
Pipes steel is 3.96 Kg
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11 screws are 0.07 Kg
2/ Buoyancy force:Using Archimedes principle
Weight for the components = masses * Gravity acceleration
Weight = (5.91+7.82+0.684+3.96+0.07) * 9.81 = 180.94 N
The force by the swept water = volume of swept water * density * Gravity
acceleration
First for the pipes:
Since it is close from both sides then the full volume is calculated like it is full
Buoyancy force for two pipes = mass of swept water * Gravity acceleration
Mass of swept water by HDPE pipe = 2 *
𝜋
4
0.22 ∗ 1 = 62.832 𝐾𝑔
Mass of swept water from the other components = volumes of components *
density of water
Mass of swept water from the other components = ((1 ∗ 1 ∗ 0.001) +
(0.05 ∗ 0.03) − (0.043 ∗ 0.023 )) ∗ 3) + (
.07
)+(6 ∗
7700
𝜋
4
∗ ( 0.2012 − 0.22 ) ∗
0.05)) ∗ 1000 = 1.615 𝐾𝑔
The total mass of swept water = 1.615+62.832 =64.447 Kg
Lower force = swept water * Gravity acceleration = 64.447 *9.81 =632.225 N
From Archimedes principle
The Buoyancy force = lower force – Weight
The Buoyancy force =632.225 - 180.94 = 451.285 N
The Buoyancy force for a given diameters and thickness for a sheet steel and
rings
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Diameters\ Thinckness
1 mm
3 mm
5 mm
200mm
451.285
304.52
179.955
300mm
1205.77
1052.71
905.28
The Designed model consists of:
-Two pipes of HDPE material with length one meter each
Fig (15) two pipes of HDPE –
the two pipes are in parallel coordinates and connected to a sheet steel by
rings” six rings 201 mm diameter each”
fig (15) Ring
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-The assembly is supported by steel pipes in which the sheet metal is located
and submerged in water
fig (16) shows the model under testing loads
3.5) feasibility study
The previous chapters lead us to believe that floating docks manufacturing has
a bright future ahead of it, since it’s related to the composite materials
improvement, the search for a lighter material that can float and carries heavy
loads always continues.
The main purpose of floating dock is transportation especially for short
distances -where using ships will be a waste of money-, besides its
manufacturing cost floating dock is economic.
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Chapter 4
Considerations and Recommendations
Generally there are a few considerations that go into the design and operation
of a floating dock:
1. Water currents and pressure play a major role on the orientation of the
objects floating on it especially when these objects (floating docks) carry many
other things on them.
2. During winters, water freezes and this might result in bending of the vertical
poles that are used for anchoring the dock. Dismantling the dock during winters
needs to be given a serious thought as well.
3. Permissions to be sought before building your own dock.
4. Place of building the Dock and its proximity to the water boundary.
5. The location of the Dock.
Taking into perspective these considerations, a certain set of guidelines need
to be adhered to. These instructions, rules and regulations and classification of
Floating Docks have been put together by the inventors themselves.
Thus, Floating Docks are a gainful proposition as against the previous one Standing Docks. Its stability, alignment, design and applications make it a good
investment.
Recommendations:The test components are not the best to prove it can float. So this is some
recommendations to improve the buoyancy force.
1- Increase the diameters for HDPE pipes ( buoyancy force for 2 pipes with
outer diameter 1000 mm and inside diameter 950 mm with 1 meter
length = 1570 Kg )
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2- Increase the thickness of sheet steel to prevent the sheet from bending.
3- Using cork to help the docks to float.
4- Using wood instead of sheet steel because it is lighter and the thickness
can increased.
5- Using galvanized steel for metal components by applying a protective
zinc coating to steel or iron, to prevent rusting. But this type of steel are
expensive.
6- Using anti-corrosion coating if the galvanized steel cannot be affordable.
Conclusion
After surveying and searching and information gathered a material is
selected to be the composite material HDPE to its light weight and can
handle heavy loads “possesses high capacity or high strength to density
ratio” beside it does not has environmental concern.
The results obtained from calculations and design show that a small
diameter of this material is fit to lift high loads and increasing the
diameter will increase the capacity.
The model manufactured is made from the HDPE pipes and connected
to a metallic sheet by rings and base to support the thick sheet.
Finally manufacturing of this model is simple and base on simple
operations as welding and linking joints but the manufacturing of the
HDPE is in low volume production and not cost effective beside there is
a lack of design data base of such materials.
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References
-Fundamentals of Physics, Sixth Edition by David Halliday,
Robert Resnick, and Jearl Walker.
- Brewer, Ted. 1993. Understanding Boat Design. New
York, NY: International Marine/Ragged Mountain Pres.
-Det Norske Veritas , rules for floating docks , 2012
-Leader Technoplast , paper sheets , 2015
-ehow.com , June 2013
-Wikipedia encyclopedia
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