because of the added veight of the vessel. Some of the steel hull 

 vessels have been overcoming this problem with the installation of 

 twin diesels, usually mounted in line on the same shaft. This adds 

 to fuel and overhaul bills, although costs are not doubled o\djig to 

 the lighter load per engine in this type of arrangement. The electrol- 

 ysis problem, cominon to both steel and wooden vessels, is accentuated 

 in tne case of steel. Few provisions are made by the builders to 

 reduce this menace. Some owners, in addition, have ejcpressed concern 

 tnat repair services for the steel vessels are not as accessible as 

 for wooden vessels. 



Wood has several advantages over steel. It is nonmagnetic 

 and has a high modulus of elasticity. On the other hand, timbers which 

 ramin damp over long periods of time are subject to decay. Modern 

 wood presei^atives can be chemically fixed in the wood and cannot be 

 wasned out. Fire retardants in combination \jith preservatives are 

 also available and used. 



In general, to avoid sJirinkage in wooden construction, tim- 

 ber used in shipbuilding should be well seasoned. Boat planking 

 belovj the vjater line should be dried so that when put into the water 

 there is a slight swelling and the joints become tighter. Decking 

 tiriibar should contain at all times 15-18 percent moisture in order 

 to prevent shrinkage and consequent opening of the seams. 



Shortcoming^ in Design and Construction of Cra ft Currently Eatployed 



Design and construction of shrimp vessels frequontly are 

 subjected to sorious criticism. Tvjo studies on vessel ofl'iciency 

 conducted by Florida research consultants vmder contract with the 

 United States Fish and Wildlife Service commented as follovis on ves- 

 sel doaign and construction: V 



Until the start of the utilization of the grooved shrimp 

 grounds off the Dry Tortugas and in the Gulf of Caiapeche, construction 

 of siii'iiiip vessels \7as carried on by various shipwrights scattered 

 along the coast lina. Construction x^as slovi but apparently quite 

 thorough. The sudden deiiiand for more and larger vessels, requiring 

 increased financing, developed a new trend in the industry. The 

 atternpts to meet this demand as rapidly as possible had their effect 



V 



The comments were combined from the following studies: 

 Harwell, Knoxjles and Associates, Su ryoy of Domes tic Shr jjiip 

 VeasGl Ei'f iclcncy ^ ?-2^^r* ^"*^ FirsT"K6search Cor'poration of 

 t'iorida, l.oilc irxuctices on Shrimp Fishing Crart, 195_5 « 



68 



