114 ON THE SUITABILITY OF CURRENT DESIGN OF SUBMARINES 
narrow waters and confront each other at relatively short ranges. As we have seen, 
the submarine is essentially a defensive arm. It finds least opportunity when it 
meets its enemy in the open sea with full freedom for maneuver. On the contrary, 
the submarine is favored when its enemy approaches a hostile shore, where his free- 
dom of maneuver is hampered by the proximity of the coast and his advantage of 
speed is thereby partially counterbalanced. 
Therefore it does not seem desirable that our navy should attempt to establish 
a defensive cordon of submarines far from our coasts in mid-ocean. For a line 
held there will be long; its distance from shore will require much time to arrive 
at and return from station, necessitating excessive numbers of ships. The enemy 
has no objective in mid-ocean and will not wait there. If he is attacked in that 
neighborhood by submarines, he has the advantage of full opportunity to maneuver 
freely at high speed. On the other hand, our submarines will gain on every one of 
the above-mentioned points if they are used for local coast defense and do not go 
far off shore—say not more than a day’srun. They may well expect to maintain 
a strip of coastal waters fairly free from the enemy and available for coast navi- 
gation, as do the English at the present time. 
Thus the size and type of coast-defense submarine of about 500 tons now fa- 
vored by our Navy Department seems the proper and logical one for American use. 
It is true that it is a much larger type of submarine which has obtained most press 
notice in the current war, but that is because the requirements of the situation were 
such that the areas best suited to the operations of German submarines were far 
from German bases. We do not foresee any strategic reasons that will require our 
submarines to operate so far from home. American coast defense does not appear 
to require the largest type of submarines. Nevertheless, the appropriation act of 
this year calls for three of a large size (800 tons), which will prove instructive and 
useful as experimental boats even if they prove to be larger and more expensive 
than necessary. 
There is a great desire on the part of every navy to provide submarines capa- 
ble of accompanying the fleet and taking part in general actions. For such a pur- 
pose a second type of submarine is necessary. 
Such a craft will be away from its base for a longer time than coast-defense 
submarines and must therefore have a larger crew and better quarters. Tactically, 
also, its requirements must be quite different. As was earlier pointed out in this 
paper, an automobile torpedo has a greater virtual range when it is fired to meet 
an approaching target than when it is fired to overtake a retreating target. Con- 
sequently an ideal torpedo-boat, whether of the surface type or of the subma- 
rine type, should have superior speed to that of its probable opponent in order 
that, however the latter turns, the torpedo-boat may assume an advantageous po- 
sition ahead of the enemy before closing to discharge the torpedo. But this is 
a difficult condition to satisfy with a fleet submarine. The standard speed of 
battleships reached 21 knots some years ago, and is now on the rise once more. 
At present 23 knots may be regarded as the normal speed for foreign battle- 
