Fresnel Class.

(Completed 1908–12.)

Twenty-two submarines of the largest sea-going Laubeuf type. Only three of these are steam driven, the others using heavy-oil engines for surface propulsion. They are in all respects similar to vessels of the Pluviôse class, and have a displacement of about 600 tons. Their speed is 12 knots above, and 9 knots below, and the armament seven 18-inch torpedoes. These vessels are fitted with stern as well as bow tubes. Their surface cruising range is over 2,000 miles.