g up with all our guns in the hope of
getting in a shot before he is able to submerge. But you may believe he
doesn't take long to get below the surface. Anyway, the sub doesn't mind
gun-fire much. They are afraid of depth charges--bombs which are
regulated so that they will explode at any depth we wish. They contain
two or three hundred pounds of high explosive, and all patrol vessels
and destroyers carry them on deck and astern. When we see a submarine
submerge we try to find his wake. Finding it, we run over it and drop a
bomb. The explosion can be felt under water for a distance of several
miles, but we have to get within ninety feet of the hull to damage it.
This damage may or may not cause the undersea boat to sink. Inside of
ninety feet, though, there isn't much doubt about the sinking.

"Patrol duty is a grind. The sea where we work is filled with wreckage
for a distance of 300 miles off shore, and you can take almost any
floating object for a periscope. Yes, we shoot at everything; ours is
not a business in which to take chances. Convoy work is more interesting
and more exciting than the round of patrol. The advantage of the convoy
over the picking up and escorting of a merchantman by a patrol-boat is
that in the convoy from six to ten destroyers can protect from ten to
thirty merchantmen, while under the patrol system one destroyer watches
one merchant craft. Convoy trips take our destroyers away from their
base from six to eight days, and they are all trying days, especially so
in dirty weather. On convoy duty no officer, and no man, has his clothes
off from start to finish. Too many things may happen to warrant any sort
of unpreparedness. Constant readiness is the watch-word.

"At night difficulty and danger increase, chiefly because of the
increased danger of collision. Collisions sometimes occur--what with the
absence of lights, the zigzag course of the ships of the convoy, and the
speed with which we travel. But as a rule the accidents are of the
scraping variety, and all thus is usually well. The convoy is purely a
defensive measure. The patrol is the offensive; in this the destroyers
and other craft go out and look for the U-boats, the idea being to hound
them out of the seas."

Then there are netting operations in which our sailors have played some
part. The netting most often used is made of stout galvanized wire with
a 15-foot mesh. This is cut into lengths of 170 feet, with a depth of 45
feet. On