18 SALVAGE EQUIPMENT USED IN RAISING SUBMARINE F-4. 
which was done upon that occasion by those men who have vindicated and demonstrated the 
efficiency of the naval diving school at the Torpedo Station at Newport, R. I., which we 
have maintained for so many years. 
NavaL Constructor FurER:—As there seems some time left, possibly a few remarks 
on Captain Niblack’s comments on submarine salvage vessels may be of interest. 
Our experience in salving the F-4 leads me to the conclusion that salvage vessels are 
not a good investment. If a salvage vessel had been available in Honolulu at the time of the 
F-4 catastrophe, the raising of the submarine might have been simplified to some extent, 
but the presence of such a vessel would not have made it possible to save the crew in any 
case, because it is probable that all hands perished within fifteen minutes after the accident 
happened; that is, long before it was even known that the vessel had met with an accident. 
The main problem was to get lifting cables under the vessel. In this a salvage vessel would 
have been of little help. The secondary problem was to provide the mechanical means for 
lifting the submarine. It is conceivable that a submarine lying disabled in shallow water 
might be brought to the surface by a salvage vessel in time to save the crew, but to make 
this possible all the conditions would have to be very favorable. In the first place, lifting 
attachments would have to be provided on all submarines corresponding to the lifting arrange- 
ments of the salvage vessel. Such lifting attachments would have to be rugged and of gen- 
erous proportions so as to take care of the large stresses involved and so as to make speedy 
connection with the lifting tackle possible. This would mean a considerable increase in the 
hull weight of submarines, which would serve no purpose except the remote contingency of 
possible use in case of accident. 
If, on the other hand, no special arrangements were provided for quickly hooking on 
the lifting gear, and if cables had to be worked under the submarine any way, the possibility 
of saving the crew would vanish because of the length of time required to perform this oper- 
ation. If, then, the salvage job is merely one of bringing the vessel up sooner or later to 
determine the cause of the accident and to recover the bodies of the crew, as it was in the 
case of the F-4, it is much more economical to provide such special means as may be indi- 
cated by the particular nature of the job, even if more time is required. It is probable that 
no two jobs could be treated in exactly the same way. The surrounding conditions will 
always vary to a considerable extent and will call for special solution of each problem. 
Then, too, if salvage vessels were provided it would be necessary to have at least five 
such craft to insure the presence of one in each general locality where our submarines oper- 
ate. This investment would be enormous as compared to the cost of an occasional salvage 
job necessitating the purchase or manufacture of special equipment. The entire cost of 
salving the F-4 was about $125,000, represented largely by the cost of the special windlasses 
and special pontoons provided for this purpose. This gear is still available should it be 
needed in the future. 
Captain Niblack referred also to the training of the divers. Several years ago the 
Bureau of Construction and Repair took up the investigation of deep-sea diving and con- 
ducted extensive tests at the New York yard to determine the factors which differentiate this 
kind of work from usual shallow-water work. The best means of providing air to the divers, 
the problem of proper telephone equipment, and the details of the type of recompression 
chamber needed to make deep-sea diving practicable, were investigated. It so happened that 
the experimental work was brought to successful termination by the Bureau of Construction 
and Repair shortly before the accident to the F-4. The men who had been trained, and 
