TO THE NEEDS OF THE UNITED STATES NAVY. 115 
ships of the most recent design, and our navy should not lag behind others 
in this respect. An ideal fleet submarine should have both surface and submerged 
speeds not less than 25 knots, and a submerged radius of at least two hours at max- 
imum speed. Unfortunately, we cannot get a quart into a pint pot, nor is such an 
ideal fleet submarine practicable. No submarine, even of as large size as 1,200 or 
1,500 tons, can get sufficiently powerful machinery into her; first because her hull 
weights must be great to withstand submergence, and, second, because she must be 
provided with two heavy systems of motive power in place of one lighter one, 
such as surface craft have. 
In the present state of engineering we shall therefore be obliged to content our- 
selves with a surface speed approaching the cruising speed of the fleet under war 
conditions, or about 20 knots. The submerged speed and radius must be very mod- 
erate; sufficient only to serve as a means of passive defense by concealment, but 
not enough for aggressive maneuvering while submerged. The mechanical limita- 
tions thus imposed upon fleet submarines restrict very greatly the tactical freedom 
of the commander-in-chief who attempts to utilize submarines in a general engage- 
ment. Other component elements of the fleet are all capable of acting in mutual sup- 
port of each other in aggressive attack upon the enemy. The fleet submarine, lim- 
ited as it is in speed, is incapable of such co-operative attack with other types, for it 
cannot force itself into the fight. The commander who seriously relies upon his 
fleet submarines in a general action must place himself upon the strategic defensive 
and so restrict his freedom of maneuver as to make it a chief objective to draw the 
enemy within the pre-established area of the submarines. It is clear that such a 
limitation is a severe handicap. It is nevertheless desirable that our fleet should 
be accompanied by submarines for use when opportunity serves. Those now build- 
ing are abreast of present possibilities, but should be improved and developed in suc- 
ceeding years as engineering progress dictates. The chief distinguishing character- 
istics for them are high surface speed with adequate surface endurance and habita- 
bility. High submerged speed and great submerged radius are comparatively sec- 
ondary affairs unless most radical improvements are brought about in the methods 
of submerged propulsion, so that high submerged mobility may be obtained without 
undue sacrifice of surface mobility. 
The conclusion to be drawn from this study is that the Navy Department has 
made a judicious decision in the combination of military characteristics which it has 
embodied in its latest designs of submarines for service with the fleet as well as 
for coast defense. 
DISCUSSION. 
THE PRESIDENT:—This interesting paper by Captain Rodgers entitled, “On the Suit- 
ability of Current Designs of Submarines to the Needs of the U. S. Navy,” is now before 
you for discussion. 
