are (a) safety at sea, (b) greater cruising range, (c) capacity to hold 

 the necessary quantity of bait, (d) bigger fish holds, (e) increase in 

 the number of fishermen employed, and (f) increased efficiency of opera- 

 tiono In addition to this tendency toward larger vessels, there are signs 

 of a standardization of design in all parts of the country, and steel 

 vessels are replacing wooden oneSo The increase in size is naturally 

 limited by the peculiar nature of the skipjack fishery, and with the present 

 character of the operations and the facilities available at fishing ports 

 steel vessels of about 150 tons are the most practical type, 



2, Cruising range and speed 



Since the recent tendency is for skipjack boats to engage also in 

 longline fishing, the boats operate the year round, fishing grounds are 

 gradually being extended farther out to sea<, and operations have become 

 more aggressive „ As a result a need has arisen for the greatest possible 

 cruising range, and along vath this attentica crast be given to speed, 

 horsepower, and type of engine, 



(1) Types of engines 



The two types under consideration are the Yaketama engine and the 

 Diesel engine. An investigation of vessels already in operation sho^s 

 that from the point of view of fuel oil consumption a 1^,0 HP Yaketama 

 engine uses Oo^ ton per day while a Diesel engine of 160 HP uses 0.7 ton. 

 Thus for its horsepower the Diessl uses less fuel than the Yaketama. 

 Lubricating oil consumption varies with the make of engine, but the 

 Diesel surpasses the Yaketama on this score by about one-fourth„ This 

 difference in oil consumption is an important point for skipjack boats, 

 which are coming to be used the year round. The Diesel engine is far 

 superior as far- as fuel consumption is concerned. 



The Yaketama engine is somewhat superior to the Diesel in power 

 output in relation to horsepower, but not enough so to offset the greater 

 fuel consumption. Diesel engines are most suitable for skipjack boats 

 and most of them are in fact adopting such engines. Howeverj Diesel 

 engines are used chiefly where more than 100 HP are required. Tne airless 

 injection type of around 200 HP, using 180 grams of fuel per horsepower 

 pel hour and 2 grams of lubricating oil^ is very dependable and durable, 

 end is the most suitable and most economical type of engine for these 

 joats, which fish in distant waters and as a rule operate for long periods 

 of time alone. 



(2) Horsepower and speed 



In recent tim.es the need for speed has been discussed from various 

 points of vieW;, but i'" th~ case of skipjack boats speed is necessary in 

 order to (a) shorts;, the dead time spent in going to and from the fishing 

 grounds, (b) increase the number of cniises which can be made during the 

 fishing season, and (c) to give the boat an advantage over other boats 

 operating on the fishing grounds„ The speed is related to the design of 

 the hull and the quality and power of the engine. Skipjack boats which 



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