Early in the war the U-boats were faster than the E's by quite two knots. Later our patrol boats became two knots faster than the later U's, while, of course, our Fleet submarines were much faster still. In gun-power the U-boats were always better, because they wanted guns more for their work. This implied that our boats were always the faster under water. In speed of diving, _i.e_. in time of getting under, there was practically no difference between the two types. In endurance the types were, ton for ton, the same, though our boats were probably far more comfortable and roomy to live in. In torpedo armament (_i.e_. in number of tubes) there was no comparison--our boats were always the more heavily armed. In wireless installations we were behindhand in 1914-15, but were ahead in 1918. In general steadiness of diving and control and in under-water handling we were always ahead. In structural strength and capacity to resist the pressures of great depths of water the enemy were probably slightly better. In hydroplane installations the American boats seem to be ahead of both of us. Neither the English nor German boats recorded a success due to the use of hydrophones, and they appear to have been little used by either Submarine Service. Both, however, used the under-water sound-signalling gear (of Fessenden type) with success, and it was found to be a useful adjunct to submarine work. Each Navy was fitting larger torpedoes and warheads in 1918 in view of the fact that the modern surface war-ship was found to be difficult to sink with the usual eighteen-inch weapon. It will be gathered from the above that we had and still have a lead in design and construction. What is far more important, however, is the lead we have kept in training and quality of the officers and men. The Germans improvised a Submarine Service--we had one already before the war, and we simply expanded it "according to plan," as more boats were needed.