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OCR for page 13
Boat Design, Construction, and
Propulsion
Traditional fishing vessels have evolved to complement the sea
conditions and fishing methods unique to each particular region.
Like fishing gear, boats have passed the test of time. Nevertheless,
traditional craft are not without their problems. They often have
a very limited range of operation and are not able to go beyond
heavily fished nearshore areas. Many will sink if swamped, provid-
ing no reserve of safety. Customary building materials are often
unavailable. Deforestation in many coastal areas has created a
scarcity of quality wood for dugout canoes and larger craft.
Traditional boats can be improved, often without radically
altering the basic design; a respect for tradition will increase their
acceptance. New vessels should have improved fishing capabilities.
Increased seaworthiness and better fuel performance would permit
fishing further offshore for previously unexploited species. Work-
ing and storage space could be increased, creating better working
conditions and facilitating an increased catch. In areas without
harbors, Leachable craft are a priority. Improved designs should
also help ensure the safety of the crew by including a second means
of propulsion and sufficient buoyancy so that the vessel remains
afloat when flooded.
Cost effectiveness is a funda~nental requirement. The value of
13
OCR for page 14
14 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES
the daily catch must exceed the operational costs and help amor-
tize the construction costs within a reasonable time. In essence,
the boat should require low investment, use minimum fuel, catch
as much fish as possible, and have a long service life.
This chapter covers some design considerations, examines
some new boat construction methods and materials, and describes
a few propulsion techniques.
DESIGN
A fishing boat may be described as a floating platform used
to transport the crew, gear, and cargo to and from the fishing
grounds and to support the crew and equipment during the fishing
operation.
Some of the major factors that affect the design of this plat-
form include:
Available funds
Available materials
Skills for building and maintenance
Size limitations dictated by water depth or requirement for
beaching
Distance to fishing grounds
Fuel costs
Type and quantity of gear used
Vessel speed requirements
Number of crew, standard of accommodation, cooking fa-
cilities
Methods of bait and catch preservation
Safety features.
Usually when a decision is made to introduce new equipment
to an existing fishery, the purpose is to fish for a new species
or to fish in a new area. New boats, new gear, or both may be
needed. In some fisheries, it may be necessary to introduce a few
larger vessels. Unless a cooperative system already exists, serious
problems of equity can arise when a small group gains significant
advantage in productivity through access to new large vessels. The
introduction of small, high-speed outboard-motor-powered boats
has also brought its share of problems. When the costs of fuel,
motor repair, and replacement reach a significant percentage of the
OCR for page 15
BOAT DESIGN CONSTRUCTION, AND PROPULSION
.-- ..~.~.~,~.~ ~--..~.~.~-~.~..~-~,.~-~-~-~ ~~ --
: :::: ::
.......... I-. -.: -a.--:---: ,- ~ ~~ ~~ ~-~--~--~ ~~ ~~ ~~ ~~ ~~ ~~ '" ''' ' ~ , ~~
15
::::: ::: j~::
........ ,., .~--~ ~,.~.
FIGURE 1.1 For some fishermen, the costs for fuel and engine repair can
approach the value of the catch. (D. Suman)
fisherman's income, the attractiveness of speed diminishes (figure
1.1~.
Small craft design should be based on the traditions of a given
region. Vessel sizes and designs that have evolved in an area are
usually well adapted to the local fishing gear and methods, the
range of operations, construction materials, the winds, and local
sea conditions. A radical departure from the traditional hull design
may not gain local acceptance.
Rafts are keelless vessels that are common In many areas
of Asia. They may be constructed of bamboo, logs, or plastic
cylinders, lashed or fastened together. These vessels are beach-
landing craft, well suited for heavy surf conditions that would
exclude many other boat types.
The kattumaran of South India is a wooden log raft that ranges
from 3 to 9 m long. Each log is individually shaped with a definite
fore and aft curvature. Longer logs are placed inboard and shorter
ones outboard, and all are lashed together. Planking is then nailed
over the logs to provide a smooth working surface.
Single-hulled vessels are most commonly used in small-scale
fisheries. Designs with a high length to beam width ratio and a
OCR for page 16
16 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES
O O;5 10 2.0 30
0 1 2 ~ ~ 5 6 7 e 9 10
(~ Sham ~ apliono I I I I I I I I
_ 1j = , it_
1 il , ii- ~ 1 ~ ?~ ! l~
.l7~
_ .
;~= _
L1 <:1
MAIN PARTICULARS
_ Lath it .11 ergo m (28 fit 6 nil
(I) acom 0~r O11 2.05 at ~ ~ to Bin)
200- , ~ ~ Dcom nodded o.ao In ~ 2 Ir an)
t~hl9~, . / 1 ~ a~ oppose. 750 ho ~ 1700 lb )
i,. ~ ~ 1__ _____
FIGURE 1.2 This FAO-developed 8.7-m boat was specifically designed for
village fishery use.
low displacements to length ratio have less resistance per unit of
displacement than do fat, heavy hull forms. Therefore, narrowing
the beam, lightening the draft,** and decreasing the displacement-
length ratio will result in less fuel consumption at a given speed.
A number of FAO-designed hulls based on these principles
have been adopted in the South Pacific. The FAO 8.7-m boat
(figure 1.2) has been designed as an easily propelled, narrow beam,
light displacement craft suitable for village fishery operations. An
outboard-powered model of this craft has been built in Western
Samoa for US$1,250. With a crew of 4 and a 20~kg catch, the
vessel can achieve a speed of 10 knots with a 20-hp outboard
motor.
Multihulled vessels, such as catamarans and trimarans, have
traditionally been used as fishing boats in the Pacific Islands.
They show promise as fishing boats in other areas, especially
where fishermen use one or two outriggers and are accustomed to
the idea of multihulIs.
*Displacement: the weight or volume of water displaced by a boat.
**Draft: the depth of water that a boat displaces.
OCR for page 17
BOAT DESIGN, CONSTRUCTION, AND PROPULSION
A" 'A
~~ ~ -- ~~ I- <,jj,,.,.,,...~.,:
: ::~ :::: ~~ ~~::~:~:::~::::~::~::~_
:~-~,.~.~,~...-~.~ ~
: ~~ ~ ~~ ~ ~^ ~ ~ ~ -
- ~ ~~ ~~ ~~ .~ .., ,,.
17
FIGURE 1.3 The Sandskipper 24 catamaran has been successfully intro-
duced in Sri Lanka. Weighing only a ton, it can carry up to 3 tons of fish
and gear. (E. W. H. Gifford)
Multihulled boats have a number of positive features for small-
scale fisheries. Their hulls have low displacement to length ratios
and high length to beam ratios (Ion" and narrow) and therefore
offer minimum resistance and are easily propelled. Moreover, the
stability of multihulIs makes them ideal candidates for sail power.
Small catamarans are lightweight and can be beached and carried
with relative ease.
Several development projects are attempting to introduce
small fishing catamarans and trimarans into areas that tradition-
ally have used monohulis. A number of catamarans have been
introduced into the tropics by Gifl.ord and Partners of Southamp-
ton, England. One of them, the Sandskipper 24 (figure 1.3), is
gaining acceptance in Sri Lanka as a Leachable fishing vessel. It
has a lateen sail and a diesel engine as propulsion options. This
vessel design has proved very satisfactory for gill netting. It can
carry a ton of gear and up to 2 tons of catch in good weather.
OCR for page 18
18 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES
CONSTRUCTION
Traditional dugout canoes and bamboo rafts are common
throughout the Third World (figure 1.4~. The construction mate-
rials are usually inexpensive and available locally. However, both
materials severely limit the hull shape and are relatively short-
lived. Wooden logs are heavy and can result in high fuel consump-
tion. While bamboo has the advantage of being lightweight, it is
not especially durable.
Wood and bamboo will remain important boat building ma-
terials in coastal fishing villages where they are readily available.
Where there is a scarcity of good wood, there may be no alter-
native to adopting new materials. Newer materials and methods
can offer many advantages that compensate for their increased
cost. The choice of material urine depend upon a number of factors
including cost, availability, longevity, ease of repair, strength, and
resistance to corrosion and rot.
Wood Construction
Timber
Planked hulls have been constructed for hundreds of years
throughout the world, and in many areas they are still very popular
and highly regarcled. Nevertheless, their importance is clearly
diminishing as new construction materials are accepted (figure
1.5~.
Several variations of planking are commonly used. In carve!
planking, the outside planking is laid edge to edge, giving the hull
a smooth surface. If the planks are very narrow (2.~4 cm wide)
and wedged together with the edges fastened, the method is called
strip planking. Marine glue or caulking is used to keep the seams
watertight.
In clinker planking, each plank overlaps the upper edge of the
plank below and is attached to it by nails driven from the outside.
This variation is strong and flexible and is ideal for such small
craft as dinghies.
Wood can be a very satisfactory boatbuilding material: it has
good resistance to chafe, gives thermal and acoustic insulation,
and allows great variation In hull shape. If good timber is avail-
able locally and is economical, it is a logical choice. However,
OCR for page 19
BOAT DESIGN, CONSTRUCTION, AND PROPULSION 19
FIGURE 1.4 Cuna tribesmen in Panama still have the logs and skills for
shaping dugout canoes. (D. Suman)
in many tropical coastal regions, suitable boatbuilding timber is
scarce and expensive. Another disadvantage is the high degree
of skill required to build a wooden boat. With only hand tools,
construction cam be very time-consuming. The hulls produced are
of medium weight and, as they become increasingly waterlogged
OCR for page 20
20 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES
FIGURE 1.5 In Martinique, a traditional planked hull wooden boat rests
on the beach; several fiberglass reinforced plastic boats float just off shore.
(D. Suman)
with age, consume large amounts of fuel. Many woods are also
subject to rot and attack from marine borers.
In Tahiti, V-bottom bonitiers are built of imported redwood
planking with local timber used for the frames. Hot dipped, gaI-
vanized carve] nails are used for the fastenings. These boats are
reported to last well, in spite of being stressed when they are run
at high speeds.
Plywood
Plywood is a sandwich of wood veneers and filler material
held together by adhesives. There are many grades of plywood,
but generally, marine plywood made with a waterproof adhesive is
required for boatbuilding. Lower grade plywoods can sometimes
be upgraded for marine use if they are coated with a polyester
resin.
Plywood is very adaptable to small boatbuilding operations.
OCR for page 21
BOAT DESIGN, CONSTRUCTION, AND PROPULSION
21
It is light, can be cut to any shape, and is easily bent. Since
sections are cut from large plywood sheets, there are fewer seams
than in planked boats. Plywood construction involves building a
framework for the hull from planks and then attaching sections of
marine plywood to this frame. The plywood hull is held together
by nails; marine glue is used to seal the seams.
Plywood boatbuilding can be quick, inexpensive, and easy. As
long as the surface, and especially the edges, of the plywood are
treated with epoxy resin or another sealer, the boat will have a
long life. However, the use of plywood does restrict the hull to
hard chine shapes, such as flat or V-bottomed boats. Moreover,
its resistance to chafe is not high.
There are many successful examples of plywood boats built
and used throughout the world.
Some 250 plywood versions of the Alia, an 8.5-m fishing cata-
maran, were built in Western Samoa in the 1970s and have sur-
vived almost a decade without hull rot or delamination. These
vessels have an emergency sail but rely on outboard motors as
their principal method of propulsion. Fishermen generally employ
these catamarans for trolling and handlining. In Fiji, more than
130 V-bottom fishing boats (8.6 m) have been constructed of ply-
wood. They are equipped with inboard diesel motors and are also
used primarily for handlining and trolling.
A plywood single outrigger canoe was designed by FAO in
1985 specifically for the waters of Papua New Guinea (figure 1.6~.
This 7-m canoe is sail-assisted and is designed to use an Hop out-
board motor. The outrigger is filled with foam and helps support
the weight of two or three persons in the canoe. In sea trials it
was shown that this new vessel equipped with an 8-hp outboard
engine was faster than a traditional dugout, powered with a 25-hp
engine, and could travel about twice as far on the same amount of
fuel. Similar plywood outrigger canoes (proas) have proved their
worthiness throughout the South Pacific where they can replace
canoes made from timber.
Plywood skiffs have wide acceptance throughout the world
as inexpensive, rugged work boats. In southern New England
(United States), plywood skiffs are extremely common and are
used for lobstering, trawling, and gill netting. With good water-
proof adhesives, these skids can have a midyear service life.
Marine plywood is also used in the stitch-and-glue technique
(figure 1.7~. Precut sections of plywood are wired together with
OCR for page 22
22 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES
FIGURE 1.6 In Papua New Guinea, plywood outrigger fishing boats have
been introduced to replace dugout canoes. The new vessels travel faster
with an 8-hp engine than do the traditional canoes with a 25-hp engine.
(Designer: O. Gulbrandsen; photo: D. Cook)
galvanized wire; the seams are then sealed with epoxy resin. The
final connection is made by bonding the epoxy resin glue with
glass fiber. Once the resin has set, the wires can be cut and a
finish applied. The product can be a strong, light boat with a life
expectancy at least as good as traditional timber vessels.
Boat construction by this technique is easy and fast. Precut
OCR for page 23
BOAT DESIGN, CONSTRUCTION, AND PROPULSION
23
sections of marine plywood may be assembled in a village work-
shop without sophisticated equipment. Skilled carpenters are not
required, but it may be necessary to import the epoxy resin and
glass fiber.
This boatbuilding technique has been introduced at the Mut-
tom Cooperative Boatyard in Tami} Nadu, southern India, in
cooperation with the Intermediate Technology Industrial Services
of England. A number of different designs have been constructed
to satisfy coastal conditions, crowded beaches, and the need for
more space to carry nets.
Another new boat design constructed by stich-and-glue meth-
ods is the ply valiam (figure 1.8~. Traditional grandams are dugouts
made from large mango trees. Having narrow hubs with lim-
itec! stability, they are airnost impossible to sad! windward except
in very light winds. Ply valIams are wider at the gunwale than
traditional boats and have increased stability. This permits the
fishermen to sail in any direction with increased safety, thus boost-
ing their fishing potential. Cheaper than the traditional craft, it
has been well accepted by fishermen. The ply valiarn is now in
service at Quilon, Kerala State, South India.
Double-hulled boats have been constructed by stitch-and-glue
methods. They can be landed on the beach and offer stability
and a large platform for fishing. One small version, the 4.8-m
Sandskipper, was also introduced into South India (figure 1.93. It
can carry half a ton of gill net and an additional ton of catch.
A plywood houri has also been designed as a replacement for
the dugouts and planked houris of the Indian Ocean (figure 1.10~.
Built from only 4 sheets of plywood, it can be rowed, paddled, or
powered with a 4-hp motor.
GLASSFIBER TAPE
ON EPOXY GLUE
1 //
~ ,^ ,,_ TIES CUTOFF, EDGE ROUNDED. GLASSFIBER TAPE
WIRE TIES JO NT Fl ED WITH RES N AND AND EPOXY RESIN
ABOUT EVERY 20 CM TIE HAMMERED WWN SLATE DUST OR EPOXY PUT
FIGURE 1.7 The stitch-and-glue construction method involves wiring ply-
wood sheets together, sealing the joint with epoxy resin, and finishing the
seal with fiberglass tape and additional resin.
OCR for page 38
38 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES
and covered with resin. Fiberglass mats are then applied at right
angles to the C-FIex. Sanding and a final finishing complete the
process.
C-FIex offers all the advantages of FRP as a construction ma-
terial, except that the strength-to-weight ratio may not be quite
as high. No mold is required, which greatly lowers costs and per-
mits clecentralized village construction. An additional advantage
is that few tools and equipment are required.
Even though the absence of a mold cuts costs, the C-FIex must
be purchased through a company in New OrIeans (United States).
In many locations, the fiberglass and laminating resin would have
to be imported, resulting in a costly product.
The International Center for Living Marine Aquatic Resources
Management (ICLARM) in the Philippines designed and con-
structed an experimental small fishing boat using defier. The
hull is 6 m long, has a shallow draft, and is beachable. Pro-
pelled by an inboard engine, the craft also has a sail-assist option.
ICLARM suggests that the fiberglass material accounts for about
two-thirds of the cost of supplies.
Aluminum
Construction of small aluminum vessels involves standard
metal-work~ng techniques. Aluminum plates are cut and bent
to fit the frame of the hull. Welding and riveting are then used to
seal the seams and fasten the plates.
Aluminum alloys are excellent materials for small vessels.
They can be shaped to almost any huh form and produce a greater
variety of shapes than glued wood can. Aluminum is also light,
which is another advantage, because it reduces the displacement
and results In low fuel consumption. In addition, aluminum shows
a high resistance to chafe, has an excellent strength-to-weight ra-
tio, and holds up well under bending stress.
Aluminum oxide forms in a thin coating on the alloy and
provides protection against corrosion. Thus, boats constructed of
this material can have great longevity.
The disadvantages of aluminum are significant. The cost of
aluminum alloys suitable for boatbuilding is very high, and the
alloys may be difficult to purchase in small quantities. Although
dents may be easily hammered out, punctures may require welding
equipment, which is not likely to be available in coastal fishing
OCR for page 39
BOAT DESIGN, CONSTRUCTION, AND PROPULSION
TABLE 1.1 Boatbuilding Materials Comparison: Construction
39
Construction Availability Skill Time to Hull
Material Cost of Materials Level Build Shape
Logs 1 1 1 2-4 3-5
Bamboo 1 1 1 1 5
Wood planking 2-3 1-5 5 5 1
Strip planking 2 2-5 3 2-3 1
Plywood sheet 2-3 3-5 2-3 2-3 3
Stitch and glue 3-4 3-5 2 2 2
Cold molded 3-4 3 2 2 1
Constant Camber 3-4 3-5 2-3 2-3 3
Fiberglass lanunate 3-5 1-5 2 1 1
FRP sandwich core 4-5 1-5 3 2-3 1
Composite laminate 5 1-5 3-5 3 1
C-Flex 3-5 2-5 2 2 1
Aluminum 4-5 1-3 2-4 2-3 2
Steel 1 1-3 2 2-3 2-3
Ferrocement 2 1-2 1-3 2-3 1
.
Scale:
Cost: 1 = lowest cost
Availability: 1 = readily available
Skill: 1 = lowest level of skill needed
Time: 1 = least time required
Hull: 1 = highest flexibility in design
villages. Moreover, aluminum ~ far more difficult to weld than
steel and requires the high temperatures of arc-welding.
More than 150 aluminum versions of the Alia were constructed
in Western Samoa. They have good fuel economy and have proven
generally satisfactory, although a few developed cracks.
The characteristics of various boatbuilding materials are sum-
marized in tables 1.1 and 1.2. In table 1.1, materials are compared
in terms of their use in construction inclu(ling cost, availability,
skill level needed, building time, and design flexibility. In table 1.2,
these same materials are compared for their performance, includ-
ing strength to weight, fuel consumption, chafe resistance, service
life, and ease and cost of maintenance.
OCR for page 40
40 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES
TABLE 1.2 Boatbuilding Materials Comparison: Performance
St rength -
Construction Weight
Material Ratio
Hull Weight
Fuel Resistance
Consumption to Chafe
Longevity Maintenance
Logs 5 5 1 3 ---
Bamboo 1 1 3 5 ---
Wood planking 3 4 2 1-3 4
Strip planking 2 4 2 1-3 4
Plywood sheet 1 3 4 3 5
Stitch and glue 1-2 2 4 3 5
Cold molded 1-2 2 4 1-3 2-3
Constant Camber 1 2 4 1-3 3
Fiberglass laminate 2 3 2-3 1-2 1-2
FRP sandwich core 1-2 1 3-4 2-3 1-2
Composite laminate 1 1 1-3 1-3 1-2
C-Flex 2-4 3-4 2 1-2 1-2
Aluminum 1 1 1-3 1 1-2
Steel 3 4 1 1-3 2-4
Ferrocement 5 5 2-3 3 2
Scale:
Strength-Weight: 1 = high ratio
Hull weight and Fuel consumption: 1 = low weight and low fuel consumption
Chafe: 1 = highly resistant
Longevity: 1 = long life
Maintenance: 1 = low cost and less difficult to maintain
PROPULSION
New technologies in propulsion include alternative fuels, al-
ternative engines, and unconventional w~nd-based methods. Al-
ternative fuels include biomass-derived gasoline and diesel-fuel
substitutes. Alternative engines include units powered by steam
and producer gas. Unusual types of sails and wind-powered rotors
complete this section.
Alternative Fuele
Both alcohol (ethanol) and vegetable oils have been examined
as potential alternative filets for small island communities. It
was proposed, for example, that it would be possible to produce
alcohol from cassava on one of the smaller islands In Fiji. Using
a simple fermentation unit and distillation column, ethanol of
95 percent purity could be manufactured and used in modified
outboard engines.*
*National Research Council. Alcohol Fuels: Options for Developing
Countries. National Academy Press, Washington, D.C. 1983.
OCR for page 41
BOAT DESIGN, CONSTRUCTION, AND PROPULSION
41
Coconut of} and other vegetable oils have been examined for
use In diesel engines. There have been three general approaches in
the testing of vegetable oils as diesel substitutes. First, the oils can
be used as 100 percent substitutes for diesel oil. In many short-
term performance tests, vegetable oils have proved almost equal to
diesel fuel. The use of pure vegetable oils in longer term endurance
tests has rarely been satisfactory, however. Problems arise with
coking and clogging of the injector ports and with fouling of the
crankcase oil. Various blends of vegetable oils and diesel of} have
also been tested. The use of 80:20 (or higher) blends of diesel of} to
vegetable of} has generally proved satisfactory in both short-term
and long-term tests. In the Philippines, however, when there was
a national program to include 5 percent coconut of} in the diesel
fuel, there were significant problems with clogging of fuel filters.
The most promising approach in the use of vegetable oils as
diesel fuels involves their chemical transformation. Through the
reaction of vegetable of} glycerides with alcohols (such as methanol
or ethanol), the original high molecular weight glycerides are con-
verted to methyl or ethyl esters, much closer in molecular size and
shape to diesel oil. Performance tests with the esters derived from
many vegetable oils have demonstrated good results in both short-
and long-term testing.
Alternative Engines
Both steam- and producer-gas-powered engines have a special
appeal for developing countries, that of fuel diversity. A wide
variety of forest and agricultural products and wastes can be used
as fuel in these systems. Using coconut-shell-derived charcoal as
fuel, producer-gas-powered fishing boats have been tested in the
Philippines.* The Intermediate Technology Development Group
(ITDG) in I,ondon has begun development and testing of a small
steam engine specifically for use in developing countries (figure
1.22~.
Wind Power
Despite the presence of favorable winds in many areas, sealing
as a means of propulsion for fishing craft in the developing world
*National Research Council. Producer Gas: Another Etuel for Motor
Transport. National Academy Press, Washington, D.C. 1983.
OCR for page 42
42 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES
.~.~.~.~.~ - .~ . ~.-~ ~ ~ ~
.... .- ~ ~ ~~ ~~ ~ ~ ~ ~ ~ ~
I- At- ~~ ... -... ..-.........
.~ ~ ..~ ~: .~ . A- - S~ ~~ I. ~ .....
.... ~ ~.~-~.~ -. ~~ ~ - -.
. ~.~ ,~,.-~,~ ~~.~,.~ ,.~ ~., ~ ~
k.~'.2 .2-~ ~ . . ~~ ~~..~ i,: ., ~,~ ~ ,..-. I,...
"my. ...'..' " ' -'-~,:.,~.~.~ A, '.'.' .'..'.. "A ~,,.~.....
,...-., I.: ,,,., ,. ~,~,~....'"' '- . :.....
i.'.. ~.-2~ I'.' I, ',~ I'm '~,~.'-~-,-. ~ ~'-2~'., 2~..,:,~.....
i ..~. it..., ...-.. 'A .,., ~~.-:~.,.-.-'~..~,~,~. :.....
.... ,, - - , ~ ,,-.- .,, ,., - ~ I ~ ~ ~ ~ I, If. ~ ,
FIGURE 1.22 The Intermediate Technology Development Group has begun
development of a small steam engine specifically designed to be used in fishing
boats in developing countries. (D. Hislop/ITDG)
has declined in recent years. Wind patterns in the tropics are gen-
erally stable and predictable; large regions benefit from regular
trade winds. In some areas, such as the northeast Indian Ocean,
the China Sea, and Malaysia, fishermen continue to use their sail-
ing skills. Large parts of Africa and Central and South America
have not developed sail craft because they lack information, suit-
able materials, or incentive. Retrofitting sails to existing vessels
can also be troublesome: hulls may not be suitably designed or
sufficiently strong to accommodate masts or the strain imposed
by sailing.
Natural or synthetic fabrics are most commonly used for sails.
Dacron has proved to be one of the most durable and efficient
materials for sails, but for most developing countries, local ma-
terials will be more practical and less expensive. Depending on
wind strength and sail configuration, a sad! area ranging between
1.9 anil 6.5 m2 (2~70 ft2) is equivalent to 1.0 hp.
Exploratory research has also been done on hard sails, such
as wingsails or airfoils. These can be up to twice as efficient as
soft sails per unit area. The best wingsails can provide thrust up
OCR for page 43
BOAT DESIGN, CONSTRUCTION, AND PROPULSION
Fan housing
vent
Cylinder
rotates to
suit wind
. ~ ~ . ~ ~ ~ ~ ~ ~ ~ ~ : ~~ ~ ~ S i S S T: ~ ~ ~ ~ ~ ~ ~ ~ ~ - - ~ ~ - - ~ ~ -A . ~ ~
43
(~
Air flows
over Ball
surface
creating
forward
thrust
~ Windward
_ turbulence
_
Windward /
vent closed
Downwind
turbulence /
~ ]~' /'
~ Downwind
,>~ vent Is open
my) Fan sucks alr
through vent
I Wind direction
Forward thrust
~ ~~ ~~:~:~ ~~,~:~:~: ~~:~ ~:~':~
, ~ A; ~ i~,4 ~ ~ 5, ~ ; ~ ~~ ; ~ i , ~ ~ ' ~ ~ 5, ' '-at ~ it; ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ :~ ~W
FIGURE 1.23 The 31-m Cousteau windskip ALCYONE can be powered by
its turbosails or its diesel engines or both. (Photo courtesy of the Cousteau
Society, a member-supported environmental organization)
to 2~30 degrees from the wind direction. The Cousteau turbosai}
windship is shown in figure 1.23. This vessel also has diesel engines,
which can be used when winds are light.
OCR for page 44
44 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES
Hnm~n Power
Arm- and leg-powered devices including oars, paddies, and
pedal-driven propellers have all been used for boat propulsion.
A highly efficient racing shell requires about 230 watts (0.3 hp)
effective power to attain a speed of 4 m per second (9 mph).
Maximum instantaneous human output is about 1,500 watts (2.0
hp.), but for a one-hour period, this decreases to about 500 watts
(0.67 hp), and for 24 hours to about 370 watts (0.5 hp).
Since humans can probably produce more power by pedaling
than any other endeavor, much could be done with pedal-powered
propellers. Rowing is a relatively inefficient way to use human
power for boat propulsion. Sculling, the use of a rear-mounted oar
fixed on a fulcrum, is significantly more efficient.
LIMITATIONS
To gain ready acceptance of fishermen, changes or improve-
ments in boat design and construction should not depart radically
from traditional designs. This concern will be automatically sat-
isfied if the local users play an important role in deciding the
changes they would like to see in their boats. What works well in
one area will not necessarily work well in another.
If new construction materials are used, they must be econom-
ical and, if possible, available locally. Local facilities must also
exist for the repair and maintenance of the vessels.
Any new design must be appropriate for the fishing gear and
methods that are locally used and, at the same time, must enhance
the safety of the fishermen.
Before its introduction, a new vessel must first be carefully
evaluated and modified as a prototype. Improvements should be
recommended and adopted only when it can be clearly proved that
they will give the fishermen greater net returns and be economi-
cally justifiable.
Improved vessel designs should not be encouraged in those
coastal areas that are heavily overfished, unless the new craft can
travel farther onshore and tap stocks that are unexploited at that
tone.
RESEARCH NEEDS
The design of small fishing boats deserves more attention.
OCR for page 45
BOAT DESIGN,CONSTRUCTION,AND PROPULSION
45
Variations of traditional designs need to be tested to deterrence
which give the best fuel and safety performances and are most
appropriate for the accepted fishing methods. A series of small,
highly efficient hull forms should be compared in single and multi-
hull configurations. These results could suggest innovative vessels
that might be easily accepted by local fishermen.
Materials' science has provided new materials that are excel-
lent for boat construction. However, the cost of many of these
materials ~ prohibitive to many fishermen. More emphasis should
be given to lower cost, locally produced construction materials.
Water-resistant glues manufactured from local materials (lignin,
for example) would be an economic alternative to expensive im-
ported epoxy or phenolic resins. Natural fibers might also serve as
substitutes for fiberglass.
SELECTED READINGS
Desi~
Food and Agriculture Organization of the United Nations (FAO). 1984
Marital of Fishing VC&BCI Design. FAO, Rome, Italy.
Fyson, J. 1986. Dc~gn of Small Fuking Vc`scl`, Fishing News Books Ltd.
Surrey, U.K.
Reinhart, J. M. 1979. Small Boat Design. ICLARM Conference Proceedings
No. 1, ICLARM, Manila, Philippines.
Todd, J., and L. G. Lepiz. 1986. An integrated approach to development of
the small-scale fisheries of the Talamanca coast of Costa Rica. Pp. 187-
193 in Proceedings of the 57th Annual Guy and Caribbean Fi~hencs Institute
F. Williams (ed). GCFI, Miami, Florida, USA.
Traung, J. O. 1967. Fishing Boats of the World. Fishing News Books Ltd.
Surrey, U.K.
Construction
General
Sleight, S. 1985. Modent Boatbuilding Matenab and Methods. International
Marine Publishing Company, Camden, Maine, USA.
Wood
Steward, R. M. 1980. Boatbuilding Manual. International Marine Publishing
Company, Camden, Maine, USA.
Harper, E. 1980. Wood V"`cl Layup. Institute of Fisheries and Marine
Technologies, St. John's, Newfoundland, Canada.
OCR for page 46
46 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES
Plywood
Intermediate Technology Development Group. 1986. South India fishermen
helped by introduction of new boats. Ir~crmcdiatc Technology Ncw8 June:1.
Payson, H. H. 1985. Instant Boas (from plywood). International Marine
Publishing Company, Camden, Maine, USA.
Wright, M., and J. Herklots. 1980. Low-cost fishing dories in Sri Lanka:
the introduction of 'stitch and glue' technology. Appropriate Technology
7~1~:24-27.
Cold-Molding
Brown, J., 1981. Knock on wood part I: plight of the canoe people. Wooden
Boat 40:78-86.
Brown, J. 1981. Knock on wood part II: the laminated dugout caper. Wooden
Boat 41:50-57.
Chambers, T. 1985. Hot ideas for cold-molded boats. Wooden Boat 63:57-60.
Nicolson, I. 1983. Cold-Moulded and Strip Planked Wood Boat6uilding. Interna-
tional Marine Publishing Company, Camden, Maine, USA.
Fe rroce me Of
Harper, E. 1981. Fcrrocemcnt Boatbuilding. Institute of Fisheries and Marine
Technology, St. John's, Newfoundland, Canada.
Hartley, R. T., and A. J. Reid. 1973. Hartlcy's Fcrrocemcnt Boat Building,
Boughtwood Printing House, Takapuna North, New Zealand.
MacAlister, G. 1980. Ferrocement and the development of small boats.
Journal of Fcrrocemcnt 10:47-50.
National Academy of Sciences. 1973. Fcrrocemcnt Application" in Developing
Contract. Washington, D.C., USA.
Sharma, P. C., and V. S. Gopalaratnam. 1980. A Fcrrocement Canoe. Asian
Institute of Technology, Bangkok, Thailand.
Fiberglass-ReinforcedF Plastic
de Schutter, J. 1985. Glassfibre reinforced polyester: its application in a
boatbuilding project in Lombok, Indonesia. Vraa~baadc 13~3~:56-62.
Vaitses, A. 1984. Boatbuilding Onc-Off in Fiberglas. International Marine
Publishing Company, Camden, Maine, USA.
C-Fiex
Kennedy, K. 1977. C-Flcz Construction Manual. International Marine Publish-
ing Company, Camden, Maine, USA.
Taylor, M. 1982. C/Flex fantastic wood sheathing. National Fisherman
November 1982.
Propulsion
Asian Development Bank. 1986. Proccedinge of the Regional Confcrenec on Sail-
Motor Prop uleion. ADB, Manila, Philippines.
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BOAT DESIGN, CONSTRUCTION, AND PROPULSION
47
Asker, G. C. F. 1985. Roller furled genoa and rigid surface wingsail, a
flexible, practical wind-assist system for commercial vessels. Journal of
Wind Enginecnng and Industrial Aerodynamics 20:61-81.
Athula, R. 1983. Sri Lanka's experience with sail-assisted fishing boats.
In: Proceeding* International CorJerenec on Sail-As~ted Commercial Fishing
Vcs~ele. Florida Sea Grant Technical Report SGR 60, University of
Florida, Gainesville, Florida, USA.
Bergeson, L., and C. K. Greenwald. 1985. Sail assist developments 1979-1985.
Procecdinge, Windlech 85, University of Southampton, Southampton, Eng-
land. Elsevier, Barking, Essex, U.K.
Blackford, B. L. 1985. Windmillthrusters: theory and experiment. Proceed-
ings, Wincitcch 85, University of Southampton, Southampton, England.
Elsevier, Barking, Essex, U.K.
Callahan, S. 1985. Go sail a kite! High Technology 5~9~:61-62.
Fyson, J. F. 1982. Low-energy fishing vessels: the use of sail power. In
Appropriate Technology for Alfcrnatinc Energy Sourecs in Fisheries, R. C. May,
I.R. Smith and D. B. Thomson (eds.~. ICLARM, Manila, Philippines.
Fukamachi, T., S. Kabaya, A. Kubota, and Y. Nagami. 1985. Sea Liz ale of
~SAF-27n How Sail and Outboards Work Together. Yamaha Motor Co., Ltd.,
Shizuoka-ken, Japan.
Lange, K. 1984. Design and testing of a fishing vessel with combined
motor/sail drive for the artisanal small-scale fishery of Sierra Leone.
Proceedings, Intcrna~onal Confcrcnec on the Dcs*n, Cor~truction, and Oper-
ation of Commercial Fishing scrawls. Florida Sea Grant Report SGR 58,
University of Florida, Gainesville, Florida, USA.
MacAlister, R. G. 1985. Application of Sail in Fuberics De?'clopment. Report
available from MacAlister, Elliot, and Partners Ltd. 56 High Street,
Lymington, Hampshire S04 9AH, U.K.
Mitchell, R. M. 1982. To Steam Launch. International Marine Publishing
Company, Camden, Maine, USA.
Morisseau, K. C. 1984. Rotor propulsion for the fishing fleet. Proceedings,
Intcrnahonal Confercnec on the Dc~gn, Construction, and Operation of Come
mercial Fishing Vce~cls. Florida Sea Grant Project SGR58. University of
Florida, Gainesville, Florida, USA.
National Academy of Sciences. 1980. Alfcrnativc FUcle for Maritime Tic.
National Academy Press, Washington, D.C., USA.
Shortall, J. W. III. 1982. Sailing Fishing Vessels Engineering Economic
Analysis. Technical Paper No. 25. Florida Sea Grant Project, University
of South Florida, Tampa, Florida, USA.
Shorthall, J. W. III. 1983. Sail-Assisted Commercial Marine Vehicles Bib-
liography and Abstracts. Technical Paper No. 28. Florida Sea Grant,
University of South Florida, Tampa, Florida, USA.
Temple, C. R. H. 1986. Sail power hoists shipping efficiency. Pacific Islands
Monthly. 57~9~:27-28.
Thomas, R. 1986. Freighters under sail. Occaru 19~3~:45-47.
Torsney, J. 1986. On the winds of change. Lifeline 5~2~:88-9.
OCR for page 48
48 FISHERIES TECHNOLOGIES FOR DEVELOP~G COUNTIES
RESEARCH CONTACTS
Agro-Forest Products Intermediate Technology Associates (AFPITA), P. O.
Box 31136, Seattle, WA 98103, USA (B. Bryant)
Asian Development Bank Project Advisor, Jalau Muara 51A, Padang Suma-
tra, Indonesia (D. Thompson)
Asker Enterprises, The Lincoln Building, Room 411, 60 East 42nd Street,
New York, NY 10165, USA (G. C. F. Asker)
Bay of Bengal Programme, Post Bag 1054, Madras 600018, India (L. Engvall)
Bundesforschungsanstalt fur Fischerei, Institut fur Fangtechnik, Palmaille 9,
Hamburg 50, Federal Republic of Germany (K. Lange)
Catfish Ltd., Carlton House, Ringwood Road, Woodlands, Southampton
S04 2HT, England (E. W. H. Gifford)
Cey-Nor Development Foundation, Ltd., Mattakkuliyaa, Sri Lanka (R.
Athula)
Department of Ocean Engineering, Florida Institute of Technology, Mel-
bourne, FL 32901, USA
Fisheries Technology Service, United Nations Food and Agriculture Orga-
nization (FAO), Via dells Terme di Caracalla, 00100 Rome, Italy (S.
Drew)
Fisheries Division, Department of Primary Industry, P.O. Box 417, Kone-
dobu, Papua New Guinea (D. C. Cook).
Intermediate Technology Development Group, Ltd., Myson House, Railway
Terrace, Rugby CV21 3HT, England (B. O'Riordon)
Kamberwood International Services, P.O. Box 550, North, VA 23128, USA
(J. Brown)
MacAlister Elliot and Partners, 56 High Street, Lymington, Hampshire S04
9AH, England (R. G. MacAli~ter)
MacLear and Harris, Inc., 28 West 44th Street, New York, New York 10036
USA (F. R. MacLear)
MIT Center for Fisheries Engineering Research, Room E38-376, 77 Mas-
sachusetts Avenue, Cambridge, MA 02139, USA (C. A. Goudey)
Oyvind Gulbrandsen, Myrsvingen 27, 4890 Grimstad, Norway
Sail Assist International Liaison Associates, Inc., 1553 Bayville Street, Nor-
folk, VA 23503, USA (K. Hill)
Sea Grant Advisory Service, 4646 W. Beach Blvd., Biloxi, MS 39531, USA
(C. David)
Seeman Fiberglass, Inc., P. O. Box 13704, 3520 Pine Street, New Orlean~,
LA 70185, USA (R. Delaune.)
Taiwan Fisheries Research Institute, 199 Ho-Ih Rd., Keelung, Taiwan (T. J.
Lee)
University of Southampton, Department of Ship Science, Southampton, S09
5NH, England (C. J. Satchwell)
Walker Wingsail Systems, Ltd., Point Hamble, Hampshire, S03 5PG England
(John Walker)
Wind Ship Development Corp., P.O. Box 440, Norwell, MA 02061, USA (L.
Bergeson)
Yamaha Motor Co., Ltd., 3380-67 Mukojima Arai-cho, Hamana-gun,
Shizuoka-ken, 431-03 Japan (T. Fukamachi)
Yee, A. A., 1441 Kapiolani Blvd., Suite 810, Honolulu, HI 96814, USA
Representative terms from entire chapter:
boat design
