During the year the system of dazzle painting for merchant ships was brought into general use.
On the operational side of the Naval Staff the work of dealing with enemy submarines before they passed out of the North Sea was taken in hand by organized hunting operations by destroyers and other patrol craft, and by the more extended use offensively of our own submarines, as vessels became available.
Considerable developments were effected in the matter of the control of mercantile traffic, and much was done to train the personnel of the mercantile marine in matters relating to submarine warfare.
Taking these subjects in detail, it will be of interest to examine the progress made during the year.
HOWITZERS The _howitzer_ as a weapon for use against the submarine when submerged was almost non-existent at the beginning of 1917, only thirty bomb-throwers, on the lines of trench-mortars, being on order.

By April of that year designs for seven different kinds of bomb-throwers and howitzers had been prepared and approved, and orders placed for 1,006 weapons, of which number the first 41 were due for delivery in May.

By the end of May the number of bomb-throwers and howitzers on order had been increased to 2,056, of eight different patterns.

Over 1,000 of these weapons fired a bomb or shell carrying a burster exceeding 90 lbs.
in weight, and with a range varying between 1,200 and 2,600 yards.

Later in the war, as we gained experience of the value of this form of attack, heavier bombs were introduced for use in the existing bomb-throwers and howitzers.