It used to be a catchword of naval correspondents that "submarine
cannot fight submarine." Well, it is true, and it isn't. What can be
done is that one submarine submerged can torpedo another submarine on
the surface: in which case submarine No. 2 is not really a submarine at
the moment. Two submarines may meet and have a gun-action, with
possible damage to one or both of them, and much entertainment to their
crews; but in such a case neither boat would be acting as a submarine.
Throughout the war our boats have been on the look-out for, and ready
to engage, any enemy submarines met with. We have had boats, in
varying numbers, since the middle of 1915 engaged definitely in
submarine-hunting--that is, those boats that could be spared from the
all-important task of watching the Bight and its approaches. The
anti-submarine boats we sent out simply proceeded to areas where, by
inference or by "information received," U-boats might be expected to
be working. The ordinary patrol boats on passage to and from their
stations, or while watching at their stations for the coming of big
ships, often met with U-boats, and naturally took the chances the gods
gave them with gun, torpedo, stem, or whatever means seemed best at the
moment.
Of course, the torpedo was the usual weapon used. A hit on a big ship,
once the destroyer screen has been avoided, is comparatively easy; a
hit on a U-boat is mighty difficult. The attacker is looking at his
target with his eye (the top prism of the periscope) only a few inches
above water-level. His view of the enemy, therefore, is confined to a
square-looking conning-tower, with heavy "jumping wires" (sweep
deflectors) running down from it to a low grey line of hull. It is
therefore difficult to exactly estimate the enemy's speed or course,
and the short time at the attacker's disposal for deciding on his
deflection and turning to bring his tubes to bear does not allow of an
accurate calculation based on bearings of the passing target. In fact,
it is usually a case of "make up your mind and shoot quick." In
addition to the handicap of the target being small, there is the
knowledge that one must be far more careful to show only a little of
the periscope during the attack, as submarines are far more on the
_qui vive_ for periscopes than big ships are. For one thing, they
know what a periscope looks like; and for another, they have more
knowledge of what a torpedo can do against craft of small buoyancy.
The moral effect of the use of submarine against submarine was probably
greater than the direct effect. It discouraged U-boats from coming to
the surface to use their guns against merchant ships, and restricted
them to their torpedo armament, which was of course limited. A U-boat
on the surface had the same sensations as a man would have who fell
overboard crossing the Indian Ocean, where the sharks are always
keeping station astern of a ship: a feeling of impatience, and anxiety
to get back to where he came from. As an instance, I will mention the
case of U 81, who, while engaged in the congenial work of pumping
shells into an English merchant ship, received two torpedoes amidships
from "E 54," who had been following operations through her periscope
since U 81 first rose to the surface. "E 54" picked up seven survivors,
one of whom was the Captain. The latter officer was somewhat damaged by
the explosions, and was in danger of drowning until "E 54's" First
Lieutenant dived for him and brought him aboard. Another survivor was
the Warrant Officer, who, on being taken below, sent a message by "E
54's" coxswain to Commander Raikes, to the effect that it was advisable
to keep a good look-out and to submerge again soon, _as there was
another U-boat diving near at hand_. Commander Raikes would no doubt
have acted on the second part of this excellent advice had it not been
necessary for him to assist the damaged steamer into harbour. If one
once begins to quote cases, it is difficult to keep from irrelevance,
but I must note here that at the moment of the sinking of U 81, the
crew of the steamer had very wisely abandoned ship, and the change from
a U-boat in full view to a ditto E boat took place so suddenly that
there was a natural misunderstanding when "E 54" stood over to tow the
boats back to their ship. The steamer's crew were living too fast in
twenty minutes for the situation to be quite clear, and in view of
their knowledge of the way in which certain U-boats had dealt with
survivors, the fact that "E 54" had to actually chase the lifeboats is
comprehensible.