ed, matchboarded and painted to provide
accommodation for the crew of picked gunners. This little ship had no
torpedo tubes and the muzzle of her gun was hidden beneath fishing nets.

There were, however, some very large and elaborately fitted "Q" boats.
These had specially constructed torpedo tubes low down in the hull,
masked 4.7-inch guns in more than one position, special chutes for depth
charges, coal bunkers arranged round the vital machinery to protect it
from shell-fire, and, moreover, were filled with wood to make them
almost unsinkable even if torpedoed.

Each such vessel was provided with a "panic party," whose duty was to
rush to the life-boats when the ship was attacked by a submarine. This
gave the final touch to the disguise, and often induced the submarine to
save further torpedoes by coming to the surface and continuing the
assault with gun-fire.

[Illustration: FIG. 16.--Method of masking a 3, 6, 12 or 13 pounder gun.
_A._ Stern of ship. _B._ Shield constructed to resemble a life-boat
which can be raised or lowered over gun _C_.]

The story of the sinking of the last German submarine in the war by the
"Q 19" will give some idea of how these vessels worked. It occurred in
the Straits of Gibraltar, about twenty-four hours before the signing of
the Armistice. The Q 19 was waiting in the Straits expecting to
intercept three big U-boats on their way back to Heligoland. About
midnight the first of these craft came along, and sighting the
innocent-looking "Q" boat prepared to attack her with gun-fire. For
nearly an hour the mystery ship "played" the submarine by pretending to
make frantic efforts to escape, but all the time allowing the
under-water craft to draw closer and closer.

The "Q" boat was under a heavy fire from the submarine, one shell
wounding eleven out of the crew of sixty, another carrying away the mast
and a portion of the funnel, but no sign of a gun was yet displayed on
board the surface ship. This withholding of fire until the last moment,
when the range has become short and the effect certain, is one of the
great nerve tests imposed on the crews of all mystery ships. It is an
essential of success, for a few wild shots at long range would disclose
the fact that the vessel was heavily armed, and the attacking submarine
would either sheer off or else submerge and use her torpedoes.

When the chase had been on for about fifty minutes, and the submarine
was only 200 yards astern, the "pan