In an article on his boats, Mr. Nordenfelt stated that they were very sensitive, and that he had purposely made them so in order that the horizontal rudder might easily maintain the boat in a horizontal position. My experience has led me to prefer great statical stability rather than sensitiveness.
Mr. Nordenfelt's boats had means for discharging the smoke from the fires under the water. This was done so as not to betray the submarine's position to surface vessels. He also seems to have been the first to incorporate torpedo tubes within his hull for the discharge of the Whitehead torpedo.
The Spanish Lieut. Isaac Peral built, in 1887, a vessel in which the motive power was supplied from electric accumulators. It was operated by the usual vertical and horizontal rudders. Its submerged control was bad, but its electric propulsive system worked well.
Mons. Goubet built several small boats during the period from 1885 to 1890 with a propeller which worked on a universal joint so arranged that the direction of thrust could be changed to drive the boat under water or to bring her to the surface when submerged. This propeller took the place of the usual vertical and horizontal rudders.
Prof. Josiah L. Tuck built, in 1885, a vessel called the Peacemaker, the novel feature of which consisted of a "caustic soda" boiler for generating steam for submerged work.
In 1886 a Mr. Waddington, of England, brought out a small electric accumulator boat with downhaul screws arranged in vertical tubes. He also used side rudders to assist in control of depth. It is reported that this vessel functioned quite successfully, but she was abandoned, and Mr. Waddington does not seem to have developed anything further.
In 1892 George H. Baker brought out an egg-shaped vessel which he ran submerged by the use of side propellers driven by bevel gears. These propellers were carried in frames so that they could be inclined to exert a thrust downward or upward, or at any desired angle so as to pull the boat downward and drive her forward at the same time. This was an improvement over Nordenfelt's side propellers, which ran on fixed vertical shafts. This vessel functioned fairly satisfactorily at slow speeds, but neither the form nor driving mechanism was suitable for the higher speeds required by modern practice.
A number of other boats were built, but there does not appear to be anything new in principle in them.
This brings us up to 1893, when the United States Government made an appropriation of $200,000 (£41,000) for a submarine boat and advertised for inventors to submit designs. This was the first time that it was officially recognized in this country that there might be possibilities in this type of boat. Most of the naval officers, however, were very sceptical of the practicability of such craft, and, from the conservative point of view, they were perhaps justified, as no satisfactory boat had been built up to that time.