THE LAST WORD IN SALVAGE SHIPS FOR 

 SUNKEN SUBMARINES 



THE sinking of submarine F-4 has 

 brought home to the people of the 

 United States an amazing deficiency in 

 the material of our fighting fleet. We 

 are sadly lacking in special craft pur- 

 posely equipped and intended to salve 

 sunken submarines. In this shortcoming 

 we lag years behind other maritime 

 powers. 



But it is not only in this direction we 

 are wanting: we still test our under-sea 

 boats in a crude and unsatisfactory man- 

 ner in seeking to prove that they are 

 strong enough to stand their maximum 

 designed submergence of two hundred 

 feet. The manner in which this trial is 

 now made practically precludes a repeti- 

 tion after first acceptance 

 from the builders, and no pro- 

 vision is made to detect hid- 

 den structural weakening due 

 to service and the stress of 

 time. 



Briefly, before one of our 

 submarines is taken over by 

 the navy from her construc- 

 tors, the boat must be taken 

 to a reasonably sheltered spot 

 on the coast where water at 



depths of 100, 150 and 200 feet, and re- 

 turned each time to the surface for ex- 

 amination. No one is in her during these 

 trial dips. Structural yielding is regis- 

 tered at various points, if such take place, 

 by means of instruments, and the sources 

 of leakage are doubtless traced back by 

 starting with tell-tale pools that may be 

 more or less remote from the actual 

 leak. 



Trials of this sort are expensive. They 

 take time much of it if the weather is 

 unfavorable, and invariably a floating 

 machine shop has to be taken along be- 

 cause the building yard may be many 

 scores of miles away. In the case of one 

 of our submarines, the builders had to 



Above: The Launching of the 

 Italian Testing Dock for Subma- 

 rines, at the Fiat-San-Giorgio 

 Shipyard Near Spezia. The Test- 

 ing Dock Consists Essentially of 

 a Big Tube Made of High Tensile 

 Steel, Permanently Sealed at One 

 End and Closed at the Other by 

 Means of a Globular Caisson. At 

 the Left: Entrance to the Testing 

 Dock. 



least two hundred feet deep can be found, send her from Philadelphia to Castme, 



There the craft is forcibly hauled down Maine, to find a suitably deep spot for 



by a wire cable passing through a ring her hull-strength submergence tests! 



in a twenty-ton anchor, successively to is largely because of these inconveniences 



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