Holland No. 7 was known as the Plunger.
BOW VIEW OF THE “HOLLAND.”
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 |
Although the Plunger was actually launched on the 7th of August, 1897, she was never completed, although for three years various alterations were carried out. The steam engines were removed and were replaced by oil motors, but by the time these modifications had been effected the Holland Torpedo-boat Company came to the conclusion that the Plunger, when completed according to the terms of the contract, would be so inferior to the more modern Hollands that they offered to refund the Government all it had paid them upon the Plunger, and all expenses connected with the contract, provided the Navy Department would enter into a contract for a new Holland. The proposition was accepted, and the money, some $94,000 odd, was accordingly refunded. A short time ago it was announced that the Plunger was being broken up.
Holland No. 8 resembled very much the later types, but as she was not entirely satisfactory, Holland No. 9 was built. This latter vessel is generally referred to as the Holland. She was the prototype of the British submarines, and her performances have excited a vast deal of interest all over the civilised world.
The dimensions of the Holland, which was constructed at Elizabeth Port, New Jersey, by Mr. Lewis Nixon, at the expense of the Holland Company, and whilst the alterations to the Plunger were still in progress, are as follows:—
| Length | 53 ft. 10 ins. |
| Diameter | 10 ft. 3 ins. |
| Height (bottom to superstructure deck) | 10 ft. 7 ins. |
| Displacement | 75 tons |
| Water ballast | 10 tons |
| Reserve buoyancy | 250 lbs. |