ew huge
submersible it seems that the ideal commerce-destroyer has been found.
This vessel possesses the necessary cruising radius to operate over
sufficient distances to control important routes; it makes a surface
speed great enough to run down cargo steamers, and has a
superstructure to mount guns of considerable power (up to six-inch).
It embodies almost all the qualifications of the light surface
cruiser, with the additional tremendous advantage of being able to
hide by submergence. To be completely successful, it must operate in
flotillas of hundreds in waters that are opaque to aerial observation.
Germany has but a limited number of these submersibles, otherwise she
would be able to crush the Allied commerce.

The ideal submersible commerce-raider should be a vessel of such
displacement that she could carry a sufficient number of large guns in
her superstructure to enable her to fight off the attack of surface
destroyers and the smaller patrol craft.[2] She should be capable of
cruising over a large radius at high speed, both on the surface and
submerged. The supersubmersible flotillas should comprise fifty or
sixty of these units. The attack on the trade routes should be made by
a number of flotillas operating at different points at unexpected
times. To-day Germany has concentrated her submarine war particularly
in the constricted waters about England. It is here that the shipping
is most congested, and therefore the harvest is richest, but it is
also easier to protect the trade routes over these limited areas of
water by patrols, nets, etc., than it would be to protect the entire
trans-oceanic length of the steamship lanes. If the submersible were
capable of dealing directly with the destroyer in gun-fighting, a
tremendous revolution would take place in the tactics of "submarine
swatting." Then it would be difficult to see how the submersible could
be dealt with.

Improvement in motive machinery is the vital necessity in the
development of the submersible. The next few years may see unexpected
strides taken in this direction. A great deal will also be
accomplished in perfecting methods of receiving sounds under water,
particularly in relation to ascertaining the direction of these
sounds. When this is done, it will be possible for the submersible
commander to tell a great deal about the positions of the vessels
above him, and thus his artificial ears will compensate to a great
extent for his blindness. By th