Whilst Mr. Whitney was Secretary of the Navy he was anxious to provide some kind of protection against gun-fire for torpedo-boats, and under suggestion he invited proposals for submarine boats. A great many designs were sent in, and two propositions to build were made by the famous Cramp firm, the designs being those of Holland and Nordenfelt. It will not be necessary to enter into any detailed comparison between the two types. Suffice it to say that while Mr. Nordenfelt screwed his boat down by using vertical screws, and held the opinion that the keel of a submarine must always be kept parallel to the surface of the water, Mr. Holland steered his boat down and up an incline by the action of horizontal rudders placed in the stern. The Holland design was accepted, because “it embodied the ideas of a fixed centre of gravity, of an exact compensation for expended weights, of a low longitudinal metacentric height, and of quick diving and rising by the effort of the propeller pushing the vessel against the resistance of her midship section only down and up inclines, the angles of which were to be determined by horizontal rudder action.” Difficulties in regard to guarantees of performance prevented the closing of a contract that year—1888—and the next year, after all preliminaries were arranged, a change in administration caused the matter to be put aside. After the lapse of some years interest in submarine boats was again aroused, and on March 3rd, 1893, Congress authorised the building of a single experimental vessel, and after a third competition of designs and other delays a contract for a Holland boat was signed two years later with the Holland Torpedo-boat Company (formed in 1895). The new vessel was to be called the _Plunger_. The long delay was owing, Mr. Holland has said, to the opposition of a few officers of Conservative spirit, who preferred to see the value of submarine boats fully established by their employment in other navies, and their place in schemes of attack and defence properly located before they could recommend their adoption in their own navy. The dimensions of the _Plunger_ are as follows:— Length 85 feet Beam 11½ feet Diameter 11½ feet Displacement 140 tons on the surface Displacement 165 tons submerged Guaranteed speed 15 knots on the surface for two hours Guaranteed speed 14 knots submerged to one foot with the conning tower above water I.H.P. (surface) 1,625 I.H.P. (submerged) 200 Motor Steam engine on surface, fed with liquid fuel Electric motor, completely submerged, giving speed of 8 knots for six hours