Of these twenty vessels five are building at Cherbourg, six at Rochefort, and the rest at Toulon. They are to unite all the best points of the existing vessels, and are intended primarily for harbour and coast defence.
PART II.
French “Submersibles,” i.e., those Fitted with Two Sources of Motive Power, One for Surface, and One for Sub-surface Propulsion.
The Narval Class.
In February, 1896, M. Lockroy, Minister of Marine, acting in conjunction with M. Bertin, Director of Material, invited designs for a submarine torpedo-boat from Frenchmen and foreigners. The commission appointed to examine the various projects decided in favour of the one sent in by M. Laubeuf. This decision was approved by the Minister, who ordered the construction of the vessel to be taken in hand, and awarded a gold medal to its inventor.
The Narval was commenced at Cherbourg in 1897, and launched on October 26, 1899, but it was not until certain modifications had been made that it was considered to be (in 1900) in a satisfactory condition to run her trials.
While the Gymnote, the Gustave Zédé, and the Morse rely solely on electricity for their motive power, the Narval can navigate in three different ways.
1. As an ordinary torpedo-boat, with water, ballast tanks empty.
2. Awash, with the dome and chimney alone above the waves, carrying a certain amount of ballast.
3. Entirely submerged with tanks full of water.
Some French writers have divided under-water craft into three classes. The first is the “Submersible”: this type is represented by the Mute of Fulton, the Stromboli, the Spuyten Duyvil, the Porter, &c. Such boats are never completely submerged, but only take in sufficient ballast to keep their decks flush with the water.