To manipulate successfully locomotive and towing torpedoes in an attack against hostile vessels, the operators must be not only unusually fearless and self-possessed, but also must possess a thorough practical knowledge of the complicated method of working and manoeuvring those weapons--in fact, they must be specialists; whilst in the case of the spar torpedo, which may be fired by contact, it is only necessary to employ men capable of handling a boat well, and possessed of dash and pluck, to ensure an attack by such means being generally successful. Of course under some circumstances, such as in a general action, when the locomotive and towing torpedoes are manipulated from specially constructed torpedo vessels, they will prove of great value, and the fish torpedo fired from a boat, in close proximity to the attacked vessel, in smooth water, and unmolested, would sink a vessel which under the same circumstances, owing to her being protected by booms, might prove impregnable to a spar torpedo attack; but such favourable conditions will not often occur in war time. [Illustration: M^{c.} EVOY'S DUPLEX SPAR TORPEDO. PLATE XLIV] As an offensive submarine weapon of defence, the Lay torpedo boat should prove of real value; and also manoeuvred from specially constructed vessels, it seems capable of being used in a variety of ways. As yet little is known of this weapon, all the experiments carried out with it having been confined to America; but now that Russia has adopted it, and one or two have also been secured by the Peruvians, its practical value will become more generally known. CHAPTER VI. TORPEDO VESSELS, BOATS, AND SUBMARINE BOATS. _EMPLOYMENT of Torpedo Ships._--Torpedo ships, that is to say, sea-going vessels, very fast, handy and impregnable, specially designed to carry and operate offensive submarine weapons, such as locomotive, towing, and the spar torpedoes, especially the former, are now considered as a necessary and valuable adjunct to a fleet, their special work being to give the coup de grâce to disabled ironclads in a general action; they will also be used to attack the ships of a blockading force, and against rival torpedo vessels. As a general rule these torpedo ships will be armed with the ram and torpedoes only, heavy guns being dispensed with, though the Nordenfelt and other machine guns will be considered necessary. _The German Torpedo Vessel Uhlan._--This torpedo vessel was built in Germany by the Stettin Engine Company, and launched in 1876.