(5) The development of the hydrophone for anti-submarine work, both from ships and from shore stations.

The next step was to fit the "fish" hydrophone in certain auxiliary patrol vessels as well as some destroyers, "P" boats and motor launches, to enter and train men to work it, and finally to organize these vessels into "submarine hunting flotillas," drill them, and then set them to their task.

This station produced the Mark II directional hydrophone of which large numbers were ordered in 1917 for use in patrol craft.