A similar vessel was built by the French government as a result of public indignation over the delay in raising the sunken _Pluviôse_. Great Britain has a salvage dock with a lifting capacity of 1000 tons. But the most remarkable craft of this kind belongs to Italy and was designed by the famous engineer Major Cesare Laurenti, technical director of the Fiat-San Giorgio works, builders of some of the world’s best submarines. She is a twin-hulled vessel, fitted not only to pick a sunken submarine from the sea bottom, but to care for it in every way, for she is also a floating dry-dock, capable of repairing two of the largest submarines, besides being a fully equipped mother-ship for a flotilla of six. With the ends of her central tunnel closed by a false stem and stern, and propelled by twin screws driven by powerful Diesel engines, she is a fast and seaworthy vessel, capable of keeping company with her flotilla on a surface cruise. She carries a sufficient armament of quick-firing guns to beat off a hostile destroyer. But the most noteworthy feature of the Laurenti dock is a long steel cylinder, capable of enduring great pressure from within, that is used to test the resisting strength of new submarines. A new boat, or a section of a proposed new type, is placed in this tube, which is filled with water that is then compressed by pumps, reproducing the effect of submergence to any desired depth. The United States navy tests each new submarine built for it by actually lowering the boat, with no one in it, to a depth of 200 feet. We have no Laurenti dock, no _Vulcan_, no sea-going salvage dock of any kind. The tender _Fulton_ has a powerful crane, but she cannot be on the Atlantic and Pacific coasts and in the Far East, simultaneously. “The difficulties encountered in raising the sunken British submarine _A-3_,” wrote Mr. R. G. Skerrett in the “Scientific American” some years ago, “have in them a note of warning for us. We are steadily adding to our flotilla of under-water boats, and yet we have no proper facilities in the government service for the prompt salvage of any of these boats should they be carried suddenly to the bottom. We have been fortunate so far in escaping serious accidents, but that is no reason for assuming that we are any more likely to be immune from disaster than any other naval service. We should profit by the catastrophes which have befallen England, Russia, France, Germany, and Japan, and no longer continue unprepared for kindred mishaps.”[19] We refused to profit and we continued unprepared. Then came a brief official cablegram from Hawaii, “Honolulu, March 25, 1915. U. S. submarine _F-4_ left tender at 9 A.M. for submerged run. Failed to return to surface.”