Above all, I believe the submarine most fitted to act as a weapon in coast-defence operations. Coast-defence submarines will probably be found to be the most important adjunct to the navies of every country whose policy is to defend their own coast lines, rather than to attempt aggressive warfare. Vessels for this purpose do not need to be of great tonnage nor of high speed. Speed is the one thing, more than anything else, which runs up the cost of the submarine vessel. While speed is desirable for the cruising submarine, it is not an essential for a defensive submarine. It is possible to get a speed of fourteen or fifteen knots in a submarine of about five hundred tons displacement, and at the same time have comfortable living quarters for the crew. A boat of this size may carry eight Whitehead torpedoes, each torpedo being capable of destroying a fifteen-million-dollar battleship, and as a five-hundred-ton displacement submarine can be built for about one-half million dollars, and is capable of carrying eight Whitehead torpedoes, potentially good for eight fifteen-million-dollar battleships, or a total of one hundred and twenty million dollars' worth of capital ships, it seems as if that would be sufficient to ask of one little submarine boat. Now to double that speed would require a much larger vessel, and would cost approximately two and one-half million dollars. A two and one-half-million-dollar boat for the defence of harbor entrances or seacoast cities would not carry as many torpedoes as five of the five-hundred-ton boats. A torpedo fired from a small boat is fully as potent as one fired from a two and one-half-million-dollar boat. These small boats could be located at five different points covering a portion of our coast, and the chances are that at least two of these smaller boats could reach an objective point on the coast line under their protection in shorter time than one large high-speed boat would be able to do. At the same cost they could cover the same area of coast line to a much better advantage, as there would be five of them to protect that area instead of one.