and the E-14 of the British Navy at
the Dardanelles, to see that it would not be impossible for the
Germans to pass in their U-boats through these mine-fields into the
open sea. It will be remembered that the E-11 and the E-14 passed
through five or more mine-fields, thence through the Dardanelles into
the Sea of Marmora, and even into the Bosphorus under seemingly
impossible conditions. Yet, in spite of the tremendous risks that they
ran, these boats continued their operations for some time, passing up
as far as Constantinople, actually shelling the city, sinking
transports, and accomplishing other feats which have been graphically
described in the stories of Rudyard Kipling. And again, if the
mine-fields were placed in close proximity to their bases, it would be
comparatively easy for German submersibles of the Lake type,
possessing appliances to enable divers to pass outboard when the
vessel is submerged, to go out and cut away the mines and thus render
them ineffective.

Nets are also used to hinder the outward passage of the submarine.
These nets can likewise be attacked and easily cut by devices with
which modern U-boats are equipped. The problem of placing these
obstacles is a difficult one, in view of the fact that the ships so
engaged are harassed by German destroyers and other enemy craft.
Outside of Zeebrugge, shallow water extends to a distance of about
five miles from the coast, and it has been suggested that a large
number of aircraft, carrying bombs and torpedoes, should be used to
patrol systematically the channel leading from that port to deep
water, with the intent of attacking the submersibles as they emerge
from this base. It is ridiculous to suppose that the Germans would not
be able to concentrate an equally large number of aircraft, to be
supported also by anti-aircraft guns on the decks of destroyers and by
the coast defenses. We have not yet won the supremacy of the air, and
it must inevitably be misleading to base any proposition on the
assumption that we are masters of that element.

The problem of bottling up the submersibles is enormously difficult,
because it necessitates operations in the enemy's territory, where he
would possess the superiority of power. I believe that the question of
operations against the submarine bases is not a naval but a military
one, and one which would be best solved by the advance of the Western
left flank of the Allied armies.

The second method is to attack