The second is the “Sous-Marin”: this type, represented by the Gymnote, Gustave Zédé, and Morse, has no sphere of action except as a totally submerged craft.

The third is the “Sous-Marin autonome à grand rayon d’action,” and is represented by the Narval type of vessel. They can be used both as ordinary torpedo-boats or submarines. We have in our classifications adopted the terms “submarine” and “submersible.”

In designing the Narval M. Laubeuf aimed at producing a disappearing vessel, which should correspond with the sea-going torpedo-boat in the same way as the Morse is partly designed to replace the torpedo-boat for coast defence.

The Narval possesses various radii of action.

1.On the surface and propelled by its steam engine—
252 miles at a speed of 12 knots for 21 hours
624 miles at a speed of 8 knots for 78 hours
2.Submerged and propelled by electricity—
25 miles at a speed of 8 knots
72 miles at a speed of 5 knots

The hull of the Narval is peculiar, being double. The interior hull is of thick steel sheets: it has a circular section, and ends in a point at its two extremities. The outer hull which envelopes it is of thin sheets; its form is that of the Gustave Zédé. The external hull is pierced with holes above and below, and at the two ends, and the sea water circulates freely between the two hulls, which allows the ship to receive a hail of small projectiles without suffering from them, the rents in its outer hull making no change in its situation.

The boat is brought to the awash condition by taking in water ballast and is steered below the surface by four horizontal float-board rudders, arranged systematically on each side of the ship, two towards the bows and two towards the stern. These “dip-rudders” are manipulated by means of a hand-wheel placed at the centre of the ship.

The Narval is not cylindrical in shape like the Morse, and her upper works are flat and form a deck.

The principal dimensions of the Narval are as follows:—

Length 111 ft. 6 in.
Extreme beam 12 ft. 4 in.
Displacement{106 tons when light.
{200 tons completely submerged.