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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
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
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
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.
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.
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,
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
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.
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
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
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.
24 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES FIGURE 1.8 In India, traditional vallams are dugout canoes made from large trees. Plywood vallams (left) have been made as substitutes using the stitch-and-glue method. (C. Palmer) Cold-Molding The boat-construction technique known as cold-molding uses veneers or thin plywood strips to build up a laminated hull. The veneers are applied in diagonally opposed layers. The thickness of the veneers varies in proportion to the hull size, but typically they are from about 2 mm to about 10 mm thick. These thin boards can be produced by a plywood mill or with a band saw or circular saw. One cold-molding method involves fabricating a mold that provides surfaces on which the planking is stapled. The veneers must be carved to a shape that will fit with their neighbors. The first layer of veneer is stapled longitudinally to the frame (figure 1.11~. Epoxy adhesive or another gap-fi~ling glue is applied to this first layer, and a second layer of veneer is stapled diagonally over the wet, uncured glue (figure 1.12~. A third layer of veneer may be placed diagonally to the second.
25 - go on > lF.~ E_ no ~ ~1 ~ 9-,8 18~: -11 OGL ~ Z ~ ~0 1 d 1 ad 4= ·_ oo _` id ~ 4= ,9 G I._ ~ - 4 V L' or d _ . ~ ._ ,= _ O on, - _ _ O U] ._ 4= O ~ 0" O.= 1 (V lo O an a _I d R 00 ·- - ~4 ~
26 FISHERIES TECHNOLOGIES FOR DEVELOP~G COUNTRIES - 3 8m~ (4Oft ~ ~` - - -; ' ~h · ql Hi °-c~ ~ _; or I ~ 1 1 1 1. ( 4 820 m ( 15 -10 ) H 0 U R I FIGURE 1.10 A plywood houri has been designed as a replacement for the planked houris of the Indian Ocean. It is intended to be built using only four sheets of plywood. (E. W. H. Gifford) After lamination has been completed, the frame can be re- moved (figure 1.13) and the staples clipped. The gunwale and keel are then attached. If necessary, a fiberglas~epoxy resin coating can be applied inside and outside the hull (figure 1.14~. A water- repellent preservative or paint will protect the wood satisfactorily. The cold-molding technique creates a very light and strong hull, resulting in low fuel consumption. These relatively thin hulls are not highly resistant to puncture but this can be improved by increasing the fiberglass-resin layer. Although in most areas it is probably easier to obtain veneers than good timber, the adhesives may have to be imported. "Constant Camber" is an improvement on this lamination technique. It requires a reusable mold shaped like a curved trellis (figure 1.15~. The hull geometry is such that the veneers can be precut and can be easily mass produced. Each veneer strip does not have to be hand carved to fit perfectly with neighboring pieces.
BOAT DESIGN, CONSTRUCTION, AND PROPULSION 27 Another great advantage ~ that one mold can produce various hull sizes and types. The mold is best suited to hull forms that have a relatively constant amount of curvature throughout, such as the long narrow hubs of multihulled vessels. However, wide-body hulls can also be produced, and craft as long as 19 m have been fabricated. Using the Constant Camber process, the veneers are bent diag- onally across the mold and stapled, as in cold-molding. Additional layers are held by epoxy resin and can be applied immediately. No screws or nails are required in the process. The staples can be left in and later cut and sanded down. Alternatively, a process called vacuum bagging can be used to eliminate the need for staples. The defects in the wood are filled with glue and even imperfect wood can be substantially strengthened. The reusable equipment for vacuum bagging costs about $500. The resulting veneer-epoxy composite is stronger than the original wood itself. The hulb are strong, light, waterproof, and rot-resistant, and have a predicted life of 20 years. E`IGURE 1.11 The first step in producing a boat by cold-molding is to staple thin strips of wood to a reusable wooden mold. (Agro-Forest Products Intermediate Technology Associates AFPITA)
28 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES ... - - ) `, ,: ~ T. ~ ~ ~< ~ I- ~ ~ ~ FIGURE 1.12 A gap-filling glue is then applied to this first layer and a second layer of wood strips applied diagonally over the wet glue. More glue and a third layer of Trips can then be added. (AFPITA) A 35-foot pane] can be laminated by several people in a matter of hours. Two half-hull panels are then sewn or glued together to form the hull (figure 1.16~. Plywood or veneers of fast-growing woods could be obtained locally in many Third World villages and the molding technique learned by village craftsmen. Liabilities are the lack of expertise In using this relatively sophisticated method. The Constant Camber technique has been used to construct a fleet of 100 paddIe-powered catamarans used by Burundi fishermen on Lake Tanganyika. These boats are especially energy efficient because they are easily paddled. A local wood was used for the veneers, but most of the equipment and adhesives as well as the expertise had to be imported. In Tuvalu in the South Pacific, several Constant Camber cata- marans transport people and cargo around the atoll lagoons (fig- ure 1.17~. These boats were originally financed by the Save-the- Children Federation but are now self-supporting. Over 100 smaller wood-epoxy boats have recently been constructed there.
BOAT DESIGN, CONSTRUCTION, AND PROPULSION 29 FIGURE 1.13 After lamination is complete, the frame can be removed from the mold and the boat finished. (AFPITA) l. B. _ _ _ _ ..~,., ~ ~ ~ ... ...~..~.~.~ .:.-.... ~~ .. I.... ~ ~ .~ _ ~-~..~ it_ -_. FIGURE 1.14 An additional resin coating can be applied to the boat to ensure a uniform protective surface. (AFPITA)
30 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES FIGURE 1.15 The Constant Camber technique uses a specially designed hull mold that permits all the wooden strips to have the same shape. (J. Brown) Non-Wood Construction Ferrocement Ferrocement is the term used to describe a steel-and-mortar composite material(figure 1.18~. It differs from conventional rein- forced concrete in that its reinforcement consists of closely spaced, multiple layers of steel mesh completely impregnated with cement mortar. Ferrocement can be formed into sections of less than an inch thick. Ferrocement reinforcing can be assembled over a light framework into the final desired shape and mortared directly in place. Ferrocement boats are usually constructed close to the water's edge because of their weight. The building site should be chosen with the size of the craft, its draft, and its launching in mind. There are five fundamental steps in Ferrocement boat con- struction: (1) The shape is outlined by a framing system.
BOAT DESIGN, CONSTRUCTION, AND PROPULSION 31 (flayers of wire mesh and reinforcing rod are latch over the framing system and tightly bound together. (3) The mortar is plastered into the layers of mesh and rod. (4) The structure is kept damp during the cure. (5) The framing system is removed (unless it h" been designed to remain as part of the internal support). There are several ways to form the shape of the boat. A rough wooden boat can be constructed as a matrix or an existing, perhaps derelict, boat can be used. Pipes or steel rods may be used to frame the shape of the huh. In the construction of Chinese sampans, a series of welded steel Dames and precast ferrocement bulkheads are erected. Layers of wire mesh are then attached to this framework and mortar applied. The steel frames and ferrocement bulkheads are left in place as part of the boat structure. Using these and similar techniques, ferrocement boats from 8 to 20 m long have been constructed. Above and below this size range there has not been enough experience to recommend this type of construction. Ferrocement hulls less than about 8 m are usually heavier than comparably sized hubs in wood, steel, FIGURE 1.16 Larger boats can be built using the Constant Camber method by producing half-hull panels and joining these. (J. Brown)
32 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES . . .. ~~-~; ~~ ; ~~ 'A ~<~ ; ..,'. .~.'.'-'~':..,.::~',~ i- ~~,';;~.,'-;','~,~,~,'-~ ','.';""~-j'~-~,~,~ Jo ..'-.-'...''".-:.'',''-'-~-.'''.-.;.~ .~, "I ;.;.',;: "a ,~ --~'.~' ''-;'';'""' "'"''''"'''' ''I ..................... 'S: Wi:~ ~\ ::'T:: ~ Jim ~ ~~; ~ Baja ~ ~ ~ ~ i. ~ i. ~ i. i. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ . ~ ~ ~ ~ ~ ~ ~ ~ FIGURE 1.17 In Tuvalu interisland transport of people and cargo is pro- vided by catamarans built using the Constant Camber method. (J. Brown) or fiberglass. This characteristic also prohibits ferrocement use in multihulled vessels. Problems with chafing, penetration by sharp objects, and salt- water corrosion of the steel mesh have also been reported. Perhaps the most positive aspect of ferrocement as a construction material is the very low cost of materials. A high percentage of materials can usually be obtained locally. Construction is straightforward and rapid. Any desired hull shape can be produced in ferrocement. Be- cause the hull is homogenous, there are no seams to leak. Damage from impact simply requires chipping away the broken concrete, reshaping the mesh support, and applying new cement. The re- pair process is easier and cheaper than repairs for many other materials. Ferrocement boats have been constructed and operate in Southeast Asia, South Asia, the South Pacific, and Africa. Many of these boats have been pilot projects, but in some cases, ferroce- ment has become a leading boatbulding material. In 1969, Cuba began construction of its first ferrocement model. During the subsequent 15 years, ferrocement has become .t
BOAT DESIGN, CONSTRUCTION, AND PROPULSION 33 the favorite construction material for Cuban boats. Cuban ship- yards and the Center for Naval Projects and Technology (C~ PRONA) have designed and produced more than 1,000 ferroce- ment vessels Tom shrimp boats to large longline fishing boats. The People's Republic of China has also opted for ferrocement sampans for use on inland waterways. Thousands are now in use on China's Grand Canal. Plastic Tubes Rafts in Taiwan have been traditionally made of bamboo; although very strong and light, this wood is also short lived. The bamboo is being replaced by sealed plastic (PVC) tubes that are 15 cm in diameter. Plastic tubing is durable and inexpensive, resistant to marine borers and rot, and does not react with salt water or become waterlogged. Nevertheless, the vessel design is very restricted. From 6 to 20 4-m-Ion" pieces of plastic tubing are fastened FIGURE 1.18 Ferrocement boats can be produced in most countries with locally available materials. (N. Vietmeyer)
34 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES FIGURE 1.19 In Taiwan, plastic tuber are used in single layers to make small rafts or in double layers to produce larger rafts. (T. J. Lee) together to construct the raft. The first meter of tubing at the bow is curved upward at 45° to minimize resistance to the water (figure 1.19~. The one-layer type of plastic raft is used in coastal fry collec- tion or in set net operation; the two-layer type is used in drift net or long net fisheries. Inboard diesel motors are generally used to
BOAT DESIGN, CONSTRUCTION, AND PROPULSION 35 propel the plastic rafts. Sail power seems to have fallen into disuse with this vessel. Fiberglass-Reinforced Plastic Fiberglass-reinforced plastic (FRP) has gained increasing ac- ceptability as a structural material for boats since the 1950s. This material was first used for pleasure craft and is now increasingly used to construct fishing boats in the Third World. FRP is a composite material made of fiberglass and a polyester resin. The fiberglass provides the material's strength, and the resin, which is absorbed by the fiberglass, allows the material to be easily shaped. After a prototype has been chosen, a female mold is manufac- tured. A polyester resin gel coat is sprayed onto the mold's surface, and then fiberglass and more resin are used to laminate the hull. After transom and keel reinforcements have been installed, the hull is removed from the mold. FRP is an outstanding construction material for boats. Vir- tuaDy any complex hull shape can be created. Because of the one-piece hull structure, leakage is practically impossible. The material is highly resistant to scratching and does not rot, rust, or corrode. Thus, less maintenance time is required, and durability is good. FRP shells have a much higher strength-to-weight ratio than similar wooden shells and are also lighter. The actual boat construction does not require high skills or sphecial tools. The major disadvantage of FRP is the cost of materials. Fiber- glass and polyester resin often must be imported at high cost. The development of the female mold required for production is an ad- ditional expense. Repair of the hull in remote areas may also be a problem. The resin presents some difficulties for the tropics because it must be stored in an air-conditioned room and replenished every 6 months. The fibers and resin also can be hazardous to the health of the workers. WelI-conceived and financed FRP fishing boats can be suc- cessfully introduced in the Third World if they are economically feasible. The modernization of the traditional canoe fleet has been a priority in Senegal. A prototype diesel-powered Leachable fish- ing boat constructed of FRP was developed by Yamaha especially for the situation there. The Loa 12.~-m canoe (figure 1.20) has the
36 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES FIGURE 1.20 FRP boats have been successfully introduced in Sene- gal. This boat has largely replaced traditional fishing canoes. (T. Fuka- machi/Yamaha) same length-to-breadth ratio as the traditional wooden canoe but offers an innovation in the hull. The bow is shaped like a ram's horn to facilitate beach landing and hauling of the canoe. The sea trials of this vessel have been satisfactory. A smaller model, the Loa 9.2 m (figure 1.21), was introduced to the Comoro Islands and the Malagasy Republic In 1983. This sail-assisted, diesel-powered canoe is meant to be a replacement for the traditional double outriggers (pirogues). The Loa 9.2 m has a double outrigger that adds stability and transfers a characteristic of the traditional canoe that is familiar to fishermen. The outrigger floats are made of FRP and the beams of aluminum pipes. It is not clear yet whether this new FRP model yields improved profits, but its sea trials are very satisfactory. A similar sort of boat evolution has occurred in Sri I,anka through FAO's Bay of Bengal Program. The traditional oru is a Pacific proa-type vessel with a single outrigger. Built of jak timber, it is seen in sizes from 15 to 40 feet. Because of the shortage of large jak timber, the FAO program designed an FRP oru that involves
BOAT DESIGN, CONSTRUCTION, AND PROPULSION 37 FIGURE 1.21 In the Comoro Islands, this sail-assisted diesel powered canoe is designed to replace the traditional double outrigger pirogues. (T. Fukamachi/Yamaha) a modification of the hull but retains the traditional rudders and · rigging. In some locations, such as the eastern Caribbean, FRP is also used to sheath traditional wooden vessels to extend their lifetime. The Bay of Bengal Program has proposed to protect the logs of South India's traditional kat;t;umaran with FRP sheathing. C-FIex C-FIex is a fiberglass planking that can be used to build boats without the standard mold required for fiberglass-reinforced plastic boat construction. C-FIex is composed of paraDe} rods of fiberglass and rein- forced polyester resin alternating with bundles of continuous fiber- glass rovings. This structure is held together by two layers of lightweight, openweave fiberglass cloth. Each plank is 112 cm wide. The planks are laid over plywood frames, tacked In place,
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
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.
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.
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.
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
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.
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.
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.
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.
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.
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