COMMERCIAL FISHERIES REVIEW 



Vol. 28, No. 8 



This, of course, slows down the improvement of designs of small hosts. Present procedures 

 are quite understandable, however, when we consider that the development of the best hull 

 form for a given set of operating circumstances would require months of work and perhaps 

 20 model tests. The tests alone would cost up to $20,000. By assembling model test data 

 over many years, however, FAO had enough information to record performance data on punch 

 cards for analysis by a computer. Accordingly, all performance information, plus dimension- 

 al description of the boats, namely, beam over draft, length over beam, fullness of midship 

 section, and power requirements in relation to speed, were fed into a digital computer at the 

 National Physical Laboratory, Teddington, England. The resulting analysis of some 600 boats 

 enabled the development of a formula for estimating the performance of any boat falling with- 

 in the range of the data. Next, FAO naval architects asked the computer to recommend de- 

 signs for specific optimum vessels on the basis of the 600 samples. The resulting answers 

 enabled the naval architects to make drawings for idealized trawlers of 40-, 55-, and 70-foot 

 lengths. Twelve-foot scale models were made and tested intensively in tanks. All three sizes 

 checked out according to the computer's calculations and performed as expected. Consider- 

 able optimism was voiced over this development. The possibilities of the computer method 

 for simplifying and improving the accuracy of the design, as well as producing boats that will 

 have maximum sea -keeping qualities and fishing performance, are almost beyond comprehen- 

 sion. 



i. 



I D i I 



The Caribbean Twin , a 70-foot steel catamaran, designed and built specifically for commercial fishing. 



The use of powered catamarans as fishing vessels was the subject of considerable dis- 

 cussion, which was focused on the 70-foot steel catamaran Caribbean Twin, recently con- 

 structed in the United States. Although the vessel is designed primarily as a stern-ramp 

 shrimp trawler, she has completed a research charter for Columbia University and now is 

 fishing shrimp out of Port Isabel, Tex. Catamarans and outriggers equipped with sails and 

 paddles, or both, have been used for thousands of years. However, powered catamarans are 

 relatively new and the Caribbean Twin is believed to be the first such vessel designed and 

 built specifically for commercial fishing. Advantages of the catamaran over single -hulled 

 craft of the same length that led to the construction of the Caribbean Twin are: the large work- 

 ing platform, greater seakindliness under most sea conditions, increased stability, excellent 

 maneuverability because of the twin engines, 20 percent greater cargo capacity, 50 percent 



