Selection of PreservativesSelection of PreservativesWater borne preservatives are best suited when Water borne preservatives are best suited when cleanliness, free from odour, low increasing wt. cleanliness, free from odour, low increasing wt. and selectivity low cost are desired.and selectivity low cost are desired. Tributyl Tin derivatives that is more suited for Tributyl Tin derivatives that is more suited for fungi insect attack as wells as antifounding fungi insect attack as wells as antifounding agent paintsagent paintsPenta chlorophenol is found to be having more Penta chlorophenol is found to be having more penetration into wood, than the copper penetration into wood, than the copper nepthanatenepthanateBy products of oil are recommended where By products of oil are recommended where high toxicity is needed.high toxicity is needed.

Choice of Treatment:Choice of Treatment:The Choice of treatment is governed by the timber speciesThe Choice of treatment is governed by the timber species

and its sapwood contant of the use to which is to be put.and its sapwood contant of the use to which is to be put.

Based on the degree of penetration, timbers are classified Based on the degree of penetration, timbers are classified

as follows for the purpose of treatment.as follows for the purpose of treatment.

1.1. Easily treatable (100% penetration) eg:- mango & HalduEasily treatable (100% penetration) eg:- mango & Haldu

2.2. 75 – 100% penetration eg:- Gurjan75 – 100% penetration eg:- Gurjan

3.3. Partially treatable (50-75% penetration) eg:- Siris, kindalPartially treatable (50-75% penetration) eg:- Siris, kindal

4.4. Difficult to treat (25 -50% penetration) eg:- DhamanDifficult to treat (25 -50% penetration) eg:- Dhaman

5.5. Non treatable (0-25 % penetration) eg:- Teak, venteakNon treatable (0-25 % penetration) eg:- Teak, venteak

Type of wood treatment methods:Type of wood treatment methods:There are many methods for treatment.There are many methods for treatment.

1.1. Surface applicationSurface application

2.2. Soaking treatmentSoaking treatment

3.3. Hot & cold. ProcessHot & cold. Process

4.4. Pressure processPressure process

5.5. Diffusion processDiffusion process

6.6. Boucherie processBoucherie process

1. 1. Surface application:Surface application: This is done either by brushing, spraying This is done either by brushing, spraying or dipping in the preservative for a short period, At least too or dipping in the preservative for a short period, At least too coat should be applied. Moisture content of 20–30% is coat should be applied. Moisture content of 20–30% is promissible.promissible.

2.2. Soaking Treatment:Soaking Treatment: The debarked timber is treated by The debarked timber is treated by submerging in the preservative solu. For a long period untill the submerging in the preservative solu. For a long period untill the required absorption of preservative has been obtained .required absorption of preservative has been obtained .

3.3. Hot & Cold process: Hot & Cold process: The debarked item is submerged The debarked item is submerged in the preservative solu. & then heated to 90in the preservative solu. & then heated to 9000c and c and maintain this temp. for a suitable period after that it is maintain this temp. for a suitable period after that it is allowed to cool untill the required absorption of allowed to cool untill the required absorption of preservative is obtained timber expands while during preservative is obtained timber expands while during cooling the residual air in the timber contracts, creating a cooling the residual air in the timber contracts, creating a partial vacuum which guses the preservative to be partial vacuum which guses the preservative to be sucked into the timbersucked into the timber

4.4. Pressure process: Pressure process: This is process of treating wood in a This is process of treating wood in a closed container of preservative. It is forced into the closed container of preservative. It is forced into the wood under pressure greater than 1 atm and is generally wood under pressure greater than 1 atm and is generally proceeded by vacuum. A temp. of 80-90proceeded by vacuum. A temp. of 80-9000C should be C should be maintained during the pressure treatment there are 2 maintained during the pressure treatment there are 2 methods of pressure treatment process:methods of pressure treatment process:

1. Full cell process1. Full cell process 2. Empty cell process2. Empty cell process The full cell process is used when max. absorption of the The full cell process is used when max. absorption of the

preservative is desired.preservative is desired.

5. Diffusion Process: 5. Diffusion Process: This process is used in case of timbers This process is used in case of timbers which are not easy to impregnate under pressure in dry which are not easy to impregnate under pressure in dry condition and also when there is danger of the timber condition and also when there is danger of the timber getting deteriorated during seasoning.getting deteriorated during seasoning.

6. Bou chrce Process: 6. Bou chrce Process: This process is applied for the This process is applied for the treatment of sapwood of green timbers soon after felling treatment of sapwood of green timbers soon after felling using any of the inorganic water soluble preservatives. In using any of the inorganic water soluble preservatives. In this process, the butt end of the pole is placed into a tank this process, the butt end of the pole is placed into a tank or reservoir or reservoir having inorganic preservative solution. The having inorganic preservative solution. The pole is inclined at 45pole is inclined at 4500 to the horizontal. Due to hydrostatic to the horizontal. Due to hydrostatic pressure, the preservative displaces the sap in the timber pressure, the preservative displaces the sap in the timber which is then forced out at the narrow end. which is then forced out at the narrow end.

Type of Vessels:Type of Vessels:1.1. WoodenWooden2.2. SteelSteel3.3. AluminiumAluminium4.4. Ferro cementFerro cement5.5. GRP vesselsGRP vessels

Wooden Vessels: Wooden Vessels: The most important factors considered in the selection of The most important factors considered in the selection of

materials are availability, suitability & economic viability wood materials are availability, suitability & economic viability wood is being used extensively for construction of vessels up to is being used extensively for construction of vessels up to about 20 m length in many countries of the world including about 20 m length in many countries of the world including India, Britain – 30mIndia, Britain – 30m

with proper selection, seasoning and treatment by preservatives with proper selection, seasoning and treatment by preservatives many timbers like vanteakmango can be brought to extensive many timbers like vanteakmango can be brought to extensive use in boat building, timber with straight and closed grain with use in boat building, timber with straight and closed grain with 10-15% moisture is the strongest specific gravity of wood is 10-15% moisture is the strongest specific gravity of wood is about 1.56.about 1.56.

Merits of wood as a boat building material:Merits of wood as a boat building material: The strength of any wood is closely related to the amount of The strength of any wood is closely related to the amount of

moisture. Wood in very wet and absolutely dry condition moisture. Wood in very wet and absolutely dry condition will have poor strength. Usual permissible range of will have poor strength. Usual permissible range of moisture is 12-18% with the max strength at 15% Inherent moisture is 12-18% with the max strength at 15% Inherent elastic properties of wood help in bending and shaping elastic properties of wood help in bending and shaping when heated and steamed wood can also stand sudden when heated and steamed wood can also stand sudden applied shock. It also has clean and smooth finish apart applied shock. It also has clean and smooth finish apart from being highly durable. With proper treatment, care and from being highly durable. With proper treatment, care and maintenance, the life of wooden boats can be increased up maintenance, the life of wooden boats can be increased up to 20-25 yrs. to 20-25 yrs.

Demerits:Demerits:

Wood being a hygroscopic material is Wood being a hygroscopic material is subjected to a rapid changes in subjected to a rapid changes in physical conditions. It absorbs nearly physical conditions. It absorbs nearly 30% of its wt. being an organic 30% of its wt. being an organic material, it is subjected to several material, it is subjected to several type of deterioration.type of deterioration.

Steel fishing vessels:Steel fishing vessels:

Steel as a boat building material was considered Steel as a boat building material was considered to replace wood. The first steel ship was build in to replace wood. The first steel ship was build in year 1878 .Basically steel is an alloy of iron and year 1878 .Basically steel is an alloy of iron and carbon. The plane low carbon steel containing carbon. The plane low carbon steel containing from 0.1-0.2% carbon are more than adequate for from 0.1-0.2% carbon are more than adequate for most of the boat construction needs. Many most of the boat construction needs. Many elements can be added to the steel in a wide elements can be added to the steel in a wide assortment of proportions, the most common ones assortment of proportions, the most common ones being Mn, Si, S, Ni, Cr, Cu, Co & Mo.being Mn, Si, S, Ni, Cr, Cu, Co & Mo.Stainless steel is not good as boat material but it Stainless steel is not good as boat material but it has excellent uses for rigging, fitting, fastenings, has excellent uses for rigging, fitting, fastenings, propellar, shafts and other applications. Medium propellar, shafts and other applications. Medium carbon steel has carbon content of 0.3-0.8% carbon steel has carbon content of 0.3-0.8% which is commonly used.which is commonly used.

Merits:Merits: A majority of steel in a ship is medium steel. A majority of steel in a ship is medium steel.

Its strength is about2.6-3.1 kg/cmIts strength is about2.6-3.1 kg/cm22.The .The specific gravity of steel is 7.84 .Steel is fire specific gravity of steel is 7.84 .Steel is fire resistantresistant

Demerits:Demerits:The steel is heavier/mThe steel is heavier/m33 than wood, Al or FRP. than wood, Al or FRP.

Steel is corrosive b/c of marine Steel is corrosive b/c of marine environment. It is brittle adjacent to the environment. It is brittle adjacent to the welds.welds.

Conclusion:Conclusion:

As long as displacement hulls As long as displacement hulls dominates the fishing industry, steel dominates the fishing industry, steel will remain the most commonly used will remain the most commonly used ship hull material.However for small ship hull material.However for small boat construction, steed is not so boat construction, steed is not so popular due to its wt. with good care popular due to its wt. with good care and maintenance, the life span of and maintenance, the life span of steel boats could increased even up steel boats could increased even up to 30-40 yrs.to 30-40 yrs.

Aluminium fishing vessels:Aluminium fishing vessels:

The first sea going hull of Al was built The first sea going hull of Al was built in France in 1892. The advancements in France in 1892. The advancements in metrological science together with in metrological science together with latest techniques in welding have latest techniques in welding have made the extensive use of made the extensive use of Aluminium possible in fishing vessel Aluminium possible in fishing vessel since 1930. since 1930.

Merits:Merits:

It becomes harder and stronger with time It becomes harder and stronger with time extremely ductile and malleable. It will extremely ductile and malleable. It will bend more easily than steel. The alloy of bend more easily than steel. The alloy of Al (Al-mg, Al-Si) are resistant to sea water Al (Al-mg, Al-Si) are resistant to sea water corrosion.corrosion.Specific gravity of Al-2.7Specific gravity of Al-2.7Modulus elasticity remains more or less Modulus elasticity remains more or less constant for all Al alloys.constant for all Al alloys.Easy to work with, can be formed, welded, Easy to work with, can be formed, welded, bolted into any form.bolted into any form.

DemeritsDemerits **Al is not compatible in sea water due to Al is not compatible in sea water due to

electrolysis. Al requires surface preparation prior electrolysis. Al requires surface preparation prior to paintaing. The initial cost of Al is much higher to paintaing. The initial cost of Al is much higher than wood and steel. Construction of Al boats than wood and steel. Construction of Al boats require a greater technical knowledge and skill.require a greater technical knowledge and skill.

**Zn Cromate Coat Zn Cromate Coat can be done for checking can be done for checking electrolysis and also prevents Galvanic corrosion electrolysis and also prevents Galvanic corrosion with salt water.with salt water.

Conclusion:Conclusion: Al is used in smaller craft, specially in inland Al is used in smaller craft, specially in inland

waters. In India, Al finds use for super structures waters. In India, Al finds use for super structures of 17.5 m steel vessels as disimproves their of 17.5 m steel vessels as disimproves their stability due to less wt. at the top life span of Al stability due to less wt. at the top life span of Al vessel is more than 40 yrs.vessel is more than 40 yrs.

Construction of wooden mechanised boat:Construction of wooden mechanised boat:

Lofting: Lofting: This is the first step in boat building. It is a This is the first step in boat building. It is a diagramatic represent of boat design which helps in diagramatic represent of boat design which helps in preparation of hull and other inner parts of boat. preparation of hull and other inner parts of boat. Mould lofting exposes & corrects the mistake made in Mould lofting exposes & corrects the mistake made in the plan 4 design.the plan 4 design.

Installation of back bone assembly: Installation of back bone assembly: The members The members of back bone assembly like keel, stem, stern, shaft of back bone assembly like keel, stem, stern, shaft long, stern post, horn timber & transom are erected long, stern post, horn timber & transom are erected first on the building stocks and securely bolted. They first on the building stocks and securely bolted. They are made using templates obtained from the mould are made using templates obtained from the mould loft. The position of frames, floors and all stations are loft. The position of frames, floors and all stations are marked on keel & Hog keel.marked on keel & Hog keel.

The first step in the actual building of the The first step in the actual building of the boat starts with laying of keel. The size of boat starts with laying of keel. The size of the keel depends on the size of the vessel. the keel depends on the size of the vessel. One piece keel is preferred. It 2 piece are One piece keel is preferred. It 2 piece are joined, a scarf joint is preferred.joined, a scarf joint is preferred.

After laying the keel other parts of back After laying the keel other parts of back bone assembly such as stem on the bone assembly such as stem on the forward with the help of stem knel and forward with the help of stem knel and transom dead woood, shaft long and horn transom dead woood, shaft long and horn timber on the aft are fitted as per the timber on the aft are fitted as per the design.design.

Fixation of moulds:Fixation of moulds:

They are made of cheaper wood and They are made of cheaper wood and are moulded on the body plan of the are moulded on the body plan of the mould loft. They are erected on the mould loft. They are erected on the backbone at respective backbone at respective stations/positions after making stations/positions after making necessary markings such as water necessary markings such as water line, deck line, sheer lineline, deck line, sheer line

4. Planking:4. Planking:

Planking keeps the boat water tight besides Planking keeps the boat water tight besides imparting strength & rigidity. The nature of imparting strength & rigidity. The nature of planking varies with the type of vessel.planking varies with the type of vessel.

Planking can be either:Planking can be either:

1.1. Carvel plankingCarvel planking

2.2. ClinkerClinker

3.3. Diagonal typeDiagonal type

Carvel planking is the system most commonly Carvel planking is the system most commonly used as this is strong, easy to repair & used as this is strong, easy to repair & cheapest.cheapest.

Fixation off Frames and Floors:Fixation off Frames and Floors:

Frames are the ribs of the vessels. Frames are the ribs of the vessels. They are lower and secured to the They are lower and secured to the keel. The other ends extend keel. The other ends extend outwards & upwards to the upper outwards & upwards to the upper deck. They confirm the shape of hull deck. They confirm the shape of hull the frames are either. Sawn type or the frames are either. Sawn type or steam bent type.steam bent type.

In case of steam bent frames, they In case of steam bent frames, they are bent to shape when hot & are bent to shape when hot & immediately fastened to the immediately fastened to the planking. When the frames are cold planking. When the frames are cold and set. The floor timbers are made and set. The floor timbers are made from mould loft pattern, fitted & from mould loft pattern, fitted & fastened to each pair of frames & fastened to each pair of frames & keel. After completion of farming, keel. After completion of farming, templates are removed and screw templates are removed and screw holds are filled with wooden nails. holds are filled with wooden nails.

Fixation of longitudinal:Fixation of longitudinal: The longitudinal are the fore & aff The longitudinal are the fore & aff

members like clamps shelves and members like clamps shelves and stringers which serve to increase the stringers which serve to increase the strength and stifness and help to prevent strength and stifness and help to prevent the tendency of sides to move in and out the tendency of sides to move in and out as the vessels sags & Hogs (Rolling & as the vessels sags & Hogs (Rolling & pitching).pitching).

Clamp is lingitudinal timber supporting deck Clamp is lingitudinal timber supporting deck beams & is the Ibeams & is the Istst internal timber to be internal timber to be fitted into the boat after framing.fitted into the boat after framing.

Shelves are long strips of wood running at intervals from Shelves are long strips of wood running at intervals from stem to stern on each side of boat and are fixed over the stem to stern on each side of boat and are fixed over the frames.frames.

7. Installation off engine and fixation of fuel tanks:7. Installation off engine and fixation of fuel tanks:

The engine bearers are shaped of the engine is installed by The engine bearers are shaped of the engine is installed by fixing over the engine bearers with bolts & keeping proper fixing over the engine bearers with bolts & keeping proper alignment. The bearers are normally supported on the floor alignment. The bearers are normally supported on the floor timbers. Simultaneously fixing of full tank is also done.timbers. Simultaneously fixing of full tank is also done.

8. Fixation of deck beams:8. Fixation of deck beams:

Deck beams are the transverse member Deck beams are the transverse member running across the deck b/w the opposite running across the deck b/w the opposite frames.frames.Deck beams provide the frame for deck Deck beams provide the frame for deck planking as well as for erecting deck planking as well as for erecting deck houses, besides keeping the transverse houses, besides keeping the transverse shape of the vessel intactshape of the vessel intactWhile fixing the beam care is taken to While fixing the beam care is taken to ensure that the central line of beams ensure that the central line of beams coincide with the central line of the boatcoincide with the central line of the boatThe deck beams are secured to the clamp The deck beams are secured to the clamp and shelves at sides and are supported by and shelves at sides and are supported by knees.knees.

Carlines are fitted in their respective Carlines are fitted in their respective positions.positions.

Half beams or spur beams that do Half beams or spur beams that do not extend to the full width off the not extend to the full width off the boat are secured to carlines at the boat are secured to carlines at the one end and bolted to the clamps on one end and bolted to the clamps on the other end. the other end.

9. Fixation of Bulk Heads:9. Fixation of Bulk Heads:

Bulk heads are fitted after the deck Bulk heads are fitted after the deck beams are bolted but before the beams are bolted but before the deck is laid.deck is laid.

These are partitions either These are partitions either transverse or longitudinal separating transverse or longitudinal separating the bull below deck in to various the bull below deck in to various compartments. compartments.

10. Deck Planking:10. Deck Planking:

The deck planks are screwed to the The deck planks are screwed to the deck beamsdeck beams

Deck planking is done in the same Deck planking is done in the same way as hull planking except that it is way as hull planking except that it is usually parallel to the central line.usually parallel to the central line.

The deck planks are to be sawn, The deck planks are to be sawn, seasoned & planked before they are seasoned & planked before they are fitted.fitted.

11.Insulation of Fish Hold:11.Insulation of Fish Hold:

Fish holds are installed and insulated Fish holds are installed and insulated & they are made water tight.& they are made water tight.

12. Fixation of Wheel house:12. Fixation of Wheel house:

Wheel house is constructed and Wheel house is constructed and secured to the hull structure beams secured to the hull structure beams are fixed and planked.are fixed and planked.

Steering Arrangements:Steering Arrangements:Rudder & Rudder shoes are fixed interior Rudder & Rudder shoes are fixed interior works involving ventilation, piping, wiring works involving ventilation, piping, wiring and steering arrangement are completed.and steering arrangement are completed.

Caulking:Caulking: It is done for the planks to It is done for the planks to make the boat water tight.make the boat water tight.

Sheathing:Sheathing: The under water hull needs The under water hull needs protection which normally provided by a protection which normally provided by a metallic sheathing. Either Cu, Al or FRP metallic sheathing. Either Cu, Al or FRP sheathing is given.sheathing is given.

Painting: Painting: After completion of all the After completion of all the works hull and other surfaces are works hull and other surfaces are painted with marine grade paint of painted with marine grade paint of desired colour. The coats of prime desired colour. The coats of prime paints. Protective oil application is paints. Protective oil application is also made wherever required.also made wherever required.

Launching & Trial:Launching & Trial: The boat is The boat is launched and trials are carried out.launched and trials are carried out.

Boat Joints: Boat Joints: Boat joint is the junction between 2 Boat joint is the junction between 2 pieces of boats commonly used joints are :pieces of boats commonly used joints are :Scarf JointScarf JointLap JointLap JointButt JointButt Joint

Scarf Joint : Scarf Joint : Most common joint used in keels, Most common joint used in keels, shelves, clamps & other longitudinal sometimes it shelves, clamps & other longitudinal sometimes it is also used in planking & Geling. It is a joint in is also used in planking & Geling. It is a joint in which ends or edges are levelled, cut in an which ends or edges are levelled, cut in an obligue angle and the entire surface remains obligue angle and the entire surface remains continuous.continuous.

Lap Joint:Lap Joint: It is joint in which 2 pieces It is joint in which 2 pieces o timber are joint in such a way that o timber are joint in such a way that one overlaps the other.one overlaps the other.

Butt Joint: Butt Joint: It is a joint in which 2 It is a joint in which 2 pieces of timber are joint end to end pieces of timber are joint end to end by using a block, known as butt by using a block, known as butt block. But joints are commonly used block. But joints are commonly used in planking.in planking.

Ferro cement fishing vessels:Ferro cement fishing vessels: Ferro cement was first introduced as boat building Ferro cement was first introduced as boat building

material in 1847. In 1940 it was successfully material in 1847. In 1940 it was successfully developed a ferro cement boat since then ferro developed a ferro cement boat since then ferro cement is highly versatile form of reinforced cement is highly versatile form of reinforced concrete made of wire mesh, sand, water and concrete made of wire mesh, sand, water and cement which posses unique quality of strength cement which posses unique quality of strength and serviceability. It consist of a reinforcement of and serviceability. It consist of a reinforcement of a no. of layers of galvanised iron, wire mesh over a no. of layers of galvanised iron, wire mesh over an arrangement of mild steel rods and fully an arrangement of mild steel rods and fully plastered with a mortar mix of sand and cement plastered with a mortar mix of sand and cement combination. The specific gravity of ferro cement combination. The specific gravity of ferro cement is 2.4-2.6is 2.4-2.6

Merits: Merits: 1.1. Easy to fabricated into complex shapes without using Easy to fabricated into complex shapes without using

moulds.moulds.2.2. It hasIt has good strength, water proof and rust proof proper good strength, water proof and rust proof proper

ties.ties.3.3. Unique feature of ferro cement boats is that specially Unique feature of ferro cement boats is that specially

under constant water contact.under constant water contact.4.4. Ferro cement boats have the longest life in water.Ferro cement boats have the longest life in water.5.5. Coast of ferro cement boats is much less than Coast of ferro cement boats is much less than

conventional wooden work.conventional wooden work.6.6. Construction is very simple.Construction is very simple.7.7. Basic material like cement, sand, steel are reading Basic material like cement, sand, steel are reading

available throughout the world available throughout the world 8.8. Easy to repairEasy to repair9.9. Resistant to fire and marine borers.Resistant to fire and marine borers.10.10. Hull does not require any protection.Hull does not require any protection.

Demerits:Demerits:1.1. Not suitable for smaller boats (>10m. Length).Not suitable for smaller boats (>10m. Length).2.2. It is heavy so need more 4p for propelling .It is heavy so need more 4p for propelling .3.3. It steel or wire mesh is exposed then corrosion It steel or wire mesh is exposed then corrosion

will be very quick.will be very quick.4.4. Heat transfer in fish hold will be very quick.Heat transfer in fish hold will be very quick.5.5. Heat transfer in fish hold will be more faster Heat transfer in fish hold will be more faster

than wood.than wood.6.6. The weakest feature of ferrocement vessel is The weakest feature of ferrocement vessel is

low resistant to penetration by sharp objects.low resistant to penetration by sharp objects.7.7. It can not be readily acceptable for mass It can not be readily acceptable for mass

production.production.

GRP fishing vessels:GRP fishing vessels:GRP is a combination of 2 basic material GRP is a combination of 2 basic material consisting of reinforcing agent like glass fibre in consisting of reinforcing agent like glass fibre in the form of thin fibre and a plastic resin. The the form of thin fibre and a plastic resin. The resulting material is known as GRP. The term resulting material is known as GRP. The term reinforcement plastic material whose physical reinforcement plastic material whose physical properties have been up graded by the addition properties have been up graded by the addition of some auxiliary material, fibres of glass etc. of some auxiliary material, fibres of glass etc. The raw materials used in GRP boat building are: The raw materials used in GRP boat building are:

1.1. Fibre glassFibre glass2.2. PlasticsPlastics3.3. CatalystCatalyst4.4. AcceleratorAccelerator5.5. Other substancesOther substances

Which include pigments fillers, Which include pigments fillers, Thixotropic paste . There are diff. Thixotropic paste . There are diff. resins like polyster, epoxy, vinyl etc. resins like polyster, epoxy, vinyl etc. Polyster is the most common. A no. Polyster is the most common. A no. of thermosetting resins such as of thermosetting resins such as henalics, melamines, silicons and henalics, melamines, silicons and epoxies are used. But polyster resins epoxies are used. But polyster resins are found the widest use in are found the widest use in reinforced plastics.reinforced plastics.

Merits:Merits:1.1. Light wt.Light wt.2.2. Highly durable Highly durable 3.3. High strength to weight ratioHigh strength to weight ratio4.4. Can be fabricated to any desired shape & size.Can be fabricated to any desired shape & size.5.5. Material is free from corrosion both in air and water.Material is free from corrosion both in air and water.6.6. No deterioration due to fungi and bacteriaNo deterioration due to fungi and bacteria7.7. Speedy construction.Speedy construction.8.8. Due to light wt. it is possible to achieve greater speed, Due to light wt. it is possible to achieve greater speed,

increased fish hold capacity and lesser hp.increased fish hold capacity and lesser hp.9.9. No leakage and hull is one piece without reams and No leakage and hull is one piece without reams and

joints.joints.10.10. High chemical and weathering resistance.High chemical and weathering resistance.11.11. Due to incorporation of pigment, hull painting can be Due to incorporation of pigment, hull painting can be

avoided.avoided.

Demerits:Demerits:

1.1. Higher initial coast.Higher initial coast.

2.2. Fabrication needs special technical Fabrication needs special technical assistance.assistance.

3.3. Some essential raw material have Some essential raw material have low storage life so require strict low storage life so require strict environmental control.environmental control.

4.4. Greater fire danger.Greater fire danger.

5.5. Needs protection against faulers.Needs protection against faulers.

Care and maintenance of fishing boatCare and maintenance of fishing boat

Wood: Wood: Wood is an organic material prome to Wood is an organic material prome to sutting by attack of marine borers and fewers.sutting by attack of marine borers and fewers.

Steel: Steel: CorossionCorossion Factors Causing detereiation of wood:Factors Causing detereiation of wood: 1. Rot: 1. Rot: Rotting is a natural phenomenon caused by Rotting is a natural phenomenon caused by

micro-organis like fungi which cause decay in the wood. micro-organis like fungi which cause decay in the wood. Organic material of wood is absorbed by these fungi. Which Organic material of wood is absorbed by these fungi. Which cuases disintegration of the cell wall and change the colour, cuases disintegration of the cell wall and change the colour, texture and strength wood become soft and spongy due to texture and strength wood become soft and spongy due to rotting most of the decay in boats occur above the water rotting most of the decay in boats occur above the water line where water can enter but can not evaporate.line where water can enter but can not evaporate.

Preventive measures:Preventive measures:

Use of heat wood.Use of heat wood.

Use of seasoned and treated wood Use of seasoned and treated wood

Allowing proper ventilation of the Allowing proper ventilation of the wood surfaces.wood surfaces.

Eliminating entery of water into the Eliminating entery of water into the boat. boat.

Marine boarers:Marine boarers:

Certain groups of animals like Certain groups of animals like Teredo, Martesia etc bore into the Teredo, Martesia etc bore into the uner part of wooden hull and destroy uner part of wooden hull and destroy the wood in long run as they the wood in long run as they consume cellulose of the wood. The consume cellulose of the wood. The damage caused is not so easily damage caused is not so easily detectable till it reached to a detectable till it reached to a dangerous level.dangerous level.

Preventive measuresPreventive measuresUse of antifouling paintsUse of antifouling paintsUnderwates sheathing made of Cu,Al Underwates sheathing made of Cu,Al or FRP.or FRP.Use of vessel in FW for few weeks.Use of vessel in FW for few weeks.Take the vessel out of water for Take the vessel out of water for about 3 weeks.about 3 weeks.It damage caused is not very severe, It damage caused is not very severe, the notes could be filled with wooden the notes could be filled with wooden plugs or any ceiling compound.plugs or any ceiling compound.

Marine foulers:Marine foulers:Certain organism settle on the submerged Certain organism settle on the submerged part of hull affecting the efficien by and part of hull affecting the efficien by and propulsion of boat is reduced and fuel propulsion of boat is reduced and fuel consumption gets increased.consumption gets increased.

These are mainly of 2 types:These are mainly of 2 types:

Microscopic:Microscopic: Bacteria, fungi, diatoms Bacteria, fungi, diatoms rotifers.rotifers.

Macroscopic: Macroscopic: Coelentrates, flat worms, Coelentrates, flat worms, tube worms, barnacies & molluscs.tube worms, barnacies & molluscs.

Preventive measures:Preventive measures:

Keep the boat in FW for sometimeKeep the boat in FW for sometime

Scrapping during dry docking Scrapping during dry docking specially for barnacles and bivalves.specially for barnacles and bivalves.

By metallic sheathingBy metallic sheathing

Application of antifouling paints on Application of antifouling paints on submerged portion.submerged portion.

Corossion:Corossion:Corrossion is a gradual disintigration of Corrossion is a gradual disintigration of metal due to chemical or electro chemical metal due to chemical or electro chemical attack by atmosphere, moisture and other attack by atmosphere, moisture and other agents this phenomenon is more common agents this phenomenon is more common in steel venels and also in wooden vessels in steel venels and also in wooden vessels having metallic sheath to the under water having metallic sheath to the under water parts of the hull. The corossion results in parts of the hull. The corossion results in thinning of plates and reduction of vessel thinning of plates and reduction of vessel speed due to roughness caused on the speed due to roughness caused on the surface of boat.surface of boat.

Control of Corossion:Control of Corossion: Corossion can be controlled by following Corossion can be controlled by following

mean:mean:Material selection and designMaterial selection and designUse of all of which resist corossion: Cu Use of all of which resist corossion: Cu base alloy and stainless steel alloy are base alloy and stainless steel alloy are resistant to corossion.resistant to corossion.By Galvanic system: Normally Zn is used By Galvanic system: Normally Zn is used to protect steel, cast iron, Brass and to protect steel, cast iron, Brass and BronzeBronzeEfficient paint systemEfficient paint systemAdequate coating of anticorossive paintsAdequate coating of anticorossive paints

Hull:Hull:

Hull is a frame work of a vessel together Hull is a frame work of a vessel together with all decks, deck houses, the inside of with all decks, deck houses, the inside of outside planking or planking but exclusive outside planking or planking but exclusive of mast, rigging and all equipments of mast, rigging and all equipments

Function:Function:

Negotiating with the rough sea Negotiating with the rough sea

Provides a platform for various fishing Provides a platform for various fishing operationsoperations

Capable of with standing stresses.Capable of with standing stresses.

Elements & Components of Hull:Elements & Components of Hull:

The forward end of the hull is called The forward end of the hull is called as bow and the afterend is called as as bow and the afterend is called as stern. The lower most part of the hull stern. The lower most part of the hull is termed as the Bottom whereas is termed as the Bottom whereas walls on either hands are referred to walls on either hands are referred to as the sides. The top of the hull is as the sides. The top of the hull is called deck. The shell of the hull is called deck. The shell of the hull is known as plating and the girder known as plating and the girder stiffening the shell is called the stiffening the shell is called the framing.framing.

Shape of the hull:Shape of the hull: Shape of the ship’s hull determines the Shape of the ship’s hull determines the

power required to drive. It reflects power required to drive. It reflects directly the ships speed and establishes directly the ships speed and establishes the limits of safety and stability.the limits of safety and stability.

According to the shape of their mid According to the shape of their mid section, hulls can be classified as:section, hulls can be classified as:

(a)(a) Flat bottomFlat bottom

(b)(b) Round bottomRound bottom

(c)(c) V-shape bottomV-shape bottom

Flat bottom:Flat bottom: Flat bottom is of very simple Flat bottom is of very simple

construction and easy to built, mostly construction and easy to built, mostly used in protected waters and used in used in protected waters and used in small craft It have a light water small craft It have a light water displacement.displacement.

V-Shape bottom:V-Shape bottom: Greater water displacement, more Greater water displacement, more

seaworthy than flat bottom but does seaworthy than flat bottom but does not have power to carry sail without not have power to carry sail without any additions.any additions.

Round bottom:Round bottom:

Suitable for both power boats and sailing Suitable for both power boats and sailing cruzes or vessels. Keel is usually wide cruzes or vessels. Keel is usually wide and heavy. It protects propellar and and heavy. It protects propellar and rudder to help in stearing.rudder to help in stearing.

According to their mode of support in the According to their mode of support in the sea, the hulls are classified as:sea, the hulls are classified as:

a.a. Planking hullPlanking hull

b.b. Displacement hullDisplacement hull

c.c. Semi displacement hullSemi displacement hull

Displacement hull:Displacement hull:

These types of hulls depend on the These types of hulls depend on the hydrostatic support or floatation for hydrostatic support or floatation for their operation. It is most common their operation. It is most common type of hull recognised for fishing type of hull recognised for fishing boats by moderate displacement boats by moderate displacement moderate speed, moderate to large moderate speed, moderate to large length and moderate capacities. It is length and moderate capacities. It is also called as “ships for all season”. also called as “ships for all season”.

Speed length Ratio:Speed length Ratio:V – Speed of the vessel in knotsV – Speed of the vessel in knots

L – Floating length of the boat or L – Floating length of the boat or

length of water line in feet.length of water line in feet.

This ratio is also called as Froude’s This ratio is also called as Froude’s

number. Based on this ratio, hull number. Based on this ratio, hull

types are:types are:

Displacement hullDisplacement hull

Semi displacement hullSemi displacement hull

Planking hullPlanking hull

Hull protection method:Hull protection method:1.1. Use of Oil: Use of Oil: Sardine oil, cod liver oil, cashew Sardine oil, cod liver oil, cashew

nut oil, shell liquid oil.nut oil, shell liquid oil.2.2. Dammar batuDammar batu: It is a resin extracted from : It is a resin extracted from

certain trees.certain trees.3.3. CoaltarCoaltar4.4. Copper sheathing: Copper sheathing: Common in mechanised Common in mechanised

boat. No need of antifouling paints.boat. No need of antifouling paints.5.5. Al. alloy sheathing: Al. alloy sheathing: CommonCommon in in

mechanised boat problem of electrolysis. So mechanised boat problem of electrolysis. So need antifouling paintneed antifouling paint

6.6. FRP sheathingFRP sheathing