Sir Stanley Colville, was indefatigable in his efforts to combat the submarine; throwers manufactured by Messrs.

Thornycroft, of Southampton, were tried and gave good results.

The arrangement was one by which depth charges could be projected to a distance of 40 yards from a vessel, and the throwers were usually fitted one on each quarter so that the charges could be thrown out on the quarter whilst others were being dropped over the stern, and the chances of damaging or sinking the submarine attacked were thus greatly increased.
As soon as the earliest machines had been tried orders were placed for large numbers and the supplies obtained were as follows: Deliveries commenced in July, 1917.
By September 1, 30 had been delivered.
By October 1, 97 had been delivered.
By December 1, 238 had been delivered.
COASTAL MOTOR BOATS At the end of 1916 we possessed 13 fast coastal motor boats, carrying torpedoes, and having a speed of some 36 knots.

They had been built to carry out certain operations in the Heligoland Bight, working from Harwich, but the preliminary air reconnaissance which it had been decided was necessary had not been effected by the end of 1916 owing to bad weather and the lack of suitable machines.
When winter set in it became impossible, with the type of aircraft then existing, to carry out the intended reconnaissance, and early in 1917 I abandoned the idea of the operations for the winter and sent the boats to the Dover Command for Sir R.Bacon to use from Dunkirk in operations against enemy vessels operating from Ostend and Zeebrugge.

They quickly proved their value, and it became evident that they would also be useful for anti-submarine work.