The story of the work of these vessels constitutes a record of gallantry, endurance and discipline which has never been surpassed afloat or ashore. The earliest vessels were fitted out during the year 1915 at Scapa, Rosyth, Queenstown and other ports, and from the very first it was apparent that they would win for themselves a place in history. The earliest success against an enemy submarine by one of these vessels was achieved by the _Prince Charles_, fitted out at Scapa, and commanded by Lieutenant Mark-Wardlaw, an officer on the Staff of Admiral Sir Stanley Colville, then Admiral Commanding the Orkneys and Shetlands. In the early months of 1917 it was decided to augment greatly the force of these special service vessels, and steps were taken to organize a separate Admiralty Department for the work. Special experience was needed, both for the selection of suitable ships and for fitting them out, and care was taken to select officers who had been personally connected with the work during the war; the advice of successful commanders of decoy ships was also utilized. At the head was Captain Alexander Farrington, under whose directions several ships had been fitted out at Scapa with great ingenuity and success. Every class of ship was brought into the service: steam cargo vessels, trawlers, drifters, sailing ships, ketches, and sloops specially designed to have the appearance of cargo ships. These latter vessels were known as "convoy sloops" to distinguish them from the ordinary sloop. Their design, which was very clever, had been prepared in 1916 by Sir Eustace T. D'Eyncourt, the Director of Naval Construction. The enemy submarine commanders, however, became so wary owing to the successes of decoy ships that they would not come to the surface until they had inspected ships very closely in the submerged condition, and the fine lines of the convoy sloops gave them away under close inspection. In the early spring of 1917 the Director of Naval Construction was asked whether the "P" class of patrol boats then under construction could be altered to work as decoy vessels, as owing to their light draught they would be almost immune from torpedo attack. A very good design was produced, and some of the later patrol boats were converted and called "P Q's." These vessels had the appearance of small merchant ships at a cursory glance. They would not, however, stand close examination owing, again, to their fine lines, but being better sea boats than the "P's," by reason of their greater freeboard, the design was continued, and they met with considerable success against submarines (especially in the Irish Sea) by ramming and depth charge tactics, the submarines when submerged probably not realizing when observing the "P Q.'s" through a periscope the speed of which they were capable.