AN ANALYSIS OF THE ISHERWOOD SYSTEM OF SHIP 



CONSTRUCTION. 



By John Flodin, B. S., M. E., Associate;. 



[Read at the twenty-seventh general meeting of the Society of Naval Architects and Marine Engineers, held 



in New York, November 13 and 14. 1919.] 



Anyone familiar with the history of the art of shipbuilding will admit that the 

 advancement within that art has been very slow. It is no doubt true that this 

 slowness has been largely due to the fact that the growth was dependent on the de- 

 velopment of the mechanical arts and the development of land transportation, but it 

 is unquestionably also true that the strong traditions, amoimting in many instances 

 to superstitions, that have enveloped all things maritime have formed a serious bar- 

 rier against all advancement. We have been told many witty and amusing tales of 

 what people thought and said about the first railroad engine and the first trolley car, 

 but only the ignorant are represented in these stories. In the shipbuilding field, on 

 the other hand, we hear of a continuous string of predictions of disasters, not from 

 people who could not be expected to know anything about the matter, but from 

 men whose experience at sea or in shipyards should have enabled them to form 

 something of an opinion of matters of this kind. Yet the prediction that the first 

 iron vessel is "bound to sink" expresses the belief of men who should have known 

 how and why a ship floats. In the same category fall the predictions regarding the 

 Great Eastern, and the expressions of mirth and derision that gave rise to the name 

 "Fulton's Folly." 



It is no wonder, then, that any departure from what had become established 

 practice would be frowned upon, and that anyone trying to introduce an improved 

 system of framing would have a hard battle to fight. A very considerable propor- 

 tion of the shipbuilders, both in this country and elsewhere, regarded with evident 

 doubt the new system devised some thirteen years ago by J. W. Isherwood. While 

 shipowners would have been quite willing to take advantage of the increased dead- 

 weight capacity claimed for the longitudinally framed ships, they generally pre- 

 ferred to wait until someone else had taken the risks of experimenting. They 

 wanted to be shown, nor can that be held against them, for who has not been mis- 

 led by too roseate advertisements? But the new system stood the test of criticism 

 and of many trials and generally gained ground in spite of the insistence of its oppo- 

 nents in characterizing it as a "get-rich-quick scheme," as a freak, and as an im- 

 position on everyone concerned. But have these opponents been entirely wrong? 

 Has the ground been gained on account of the increased deadweight cargo capa- 

 city — granting that that claim be true — at the expense of strength and durability ? 



