tuna fleet had been restricted to vessels of 100-ton capacity operating 

 yrith motherships or some other form of cargo carriers, the tuna fishing 

 operation might now be on a sounder economic basis. Smaller vessels 

 with proportionately increased cargo capacity through the use of high 

 speed Diesels may be an answer. However this must be considered 

 against the background of mothership oi^erations which have been tried 

 with the practice being generally discontinuedo 



The use of Diesel-electric proptilsion is under preliminary study 

 because of greater flexibility of control, ease of handling, smooth 

 propulsion, elimination of propulsion shaft aligrment difficulties, 

 and reduction of engine room space by combining the functions of the 

 present main propulsion engines and the auxiliary engines used for 

 electrical power service. The auxiliary engines and generators are 

 highly efficient by modern engineering practice o The only fault 

 may be inadequate capacity in some of the older vessels caused by the 

 addition of new electrical loads for advance equipment. 



Propellers have been installed on many thousands of fishing 

 vessels and a great amount of design experience has been accumulated. 

 As a consequence there appears to be little prospect of improvement in 

 conventional propellers. Limited experience with variable pitch 

 propellers has demonstrated that the control mechanism is subject to 

 failure and that conventional propellers will result in equal or 

 increased speeds of the vessel at a given power input. 



Vessel Design 



A tuna clipper is designed to carry the maiximum load and the 

 necessary mechanical and electrical equipment in the minimim over- 

 all length of hull. There are definite possibilities for improved 

 hull design for easier running lines and seakindliness, but these 

 designs are not compatible with maximum loads per foot of over-all 

 length. The tuna vessel owners have decided that carrying capacity 

 cannot be sacrificed for cleaner lines, desirable deadrise and flared 

 bows. The cost of a hull is predicated on a relatively uniform price 

 per foot of over-all length among builders for definite size ranges 

 of vessels and types of construction. Essentially the buyer of a tuna 

 boat is purchasing a definite number of tons carrying capacity for a 

 fixed sum of money. Most fishing vessels are designed for the 

 exploitation of specific fisheries with a specific type of gear. The 

 tuna clipper is a highly-apecialized type developed over many years 

 and with the assumption that the resource is adequate to support such 

 a highly specialized vessel throughout its useful life. Purse seiners, 



20A 



