116 ON THE SUITABILITY OF CURRENT DESIGN OF SUBMARINES 
Proressor W. Hovcaarp, Member :—Captain Rodgers especially emphasizes the defen- 
sive nature and capabilities of submarines and from this premise makes his deductions as to 
their use and the best type to be adopted. He conceives the principal duty of the submarine 
of the United States Navy to be local coast defense, and concludes logically that boats of 
500 tons displacement should be the standard type. Beyond that, Captain Rodgers recom- 
mends only one type, the so-called fleet submarine, which is of the largest size that can be ef- 
ficiently constructed, probably of from 1,200 to 1,500 tons submerged displacement. 
Now it must be borne in mind that one of the most serious shortcomings of submarines 
is lack of endurance. It appears from the experience of the European war that even for 
large boats the maximum time of continuous sea service under war conditions is about three 
weeks, if the efficiency of the personnel and matériel is to be maintained at a reasonable stand- 
ard. This limitation is imposed, not so much by the quantity of fuel or the number of tor- 
pedoes which the boat can carry, but more by the physical endurance of the crew. It is 
clear that larger boats are in this respect superior to smaller, being more seaworthy and 
roomy and allowing much in the way of comfort which must be denied the crew of smaller 
vessels. The period of effective service is, therefore, considerably shorter for smaller boats 
than for larger. This point is of particular importance for the submarines of the United 
States Navy, because their service lies chiefly on the open ocean, even when on patrol duty 
near a base, and the distances to be covered along the extensive coast lines of the country are 
very great. 
Speaking first of defensive warfare, the most important and typical case from a 
strategic and, perhaps I should say, academic point of view, is a war with England, for this 
is the only country which single-handed can force a strictly defensive attitude on the United 
States Navy. I am, in fact, referring to this case merely as a strategical possibility—not as 
a political probability—but no study of the strategic conditions of this country would be 
complete without considering it, however remote it may be. If the navy is prepared to meet 
this contingency, it is prepared to meet all. 
Apart from local coast defense, for which submarines of 500 tons or less will be suitable, 
and of which undoubtedly a great number will be required, the United States Navy in such 
a war would need boats that would carry out a vigorous aggressive defensive. It would be 
necessary to have boats which could harass the blockading fleet—not only the small, fast 
vessels stationed near the shore, but also the large blockading ships, which would probably 
keep going at a great distance from the coast. Submarines would be required also for block- 
ading or watch duty off Halifax, the Bermudas, Nassau, and in summer time in Cabot Strait, 
and even in the Strait of Belle Isle, about one thousand miles from the nearest base of the 
United States. In the Caribbean Sea, Jamaica, Trinidad and other points would have to be 
watched, and in the Pacific, Vancouver. If the Panama Canal fell in the hands of the enemy, 
submarines would be wanted for its blockade at both terminals. Submarines would be required 
finally to operate in conjunction with the fleet when it made sorties. For all these duties, 
most of which require long voyages and protracted service in the open sea on stations far 
from the base, large boats are needed, not necessarily of the size of fleet submarines, but 
probably of at least some 800 tons displacement. Smaller boats would be unsatisfactory for 
such service, because they could keep their station only for shorter periods and would thus 
require frequent relief. 
In a war against a coalition of other powers, the navies of which are in the aggregate supe- 
rior to that of the United States, large submarines will again be needed for attack on the lines 
