Built at Fiat-San Giorgio Co., Spezia, 1915-1916. Displacement 41.00 tons with dry dock empty and 14’ draught, 4.130 tons with dock-gate open and dock flooded to float a submarine inwards and with a draught of 14½”, 4.560 tons with dock-gate closed and dock filled with a submarine with a draught of 15 feet, 6.60 tons with dock-gate closed and dock filled with a submarine while hydraulic pressure tested and a draught of 20½’ and 4.615tons with an empty dock and closed dock-gate but raising a submarine with the two cranes aft with a draught of 15’. Dimensions 328’(between perpendiculars) x 52’. Her 2 cylinder Fiat diesel engines provided 4.100 bhp allowing a speed of 15 knots and a range of 400 miles by a speed of 10 knots. Fuel capacity was 400 tons with another 240 tons available for the submarines. She was armed with 4-4” guns and 2 smaller guns. Her crew numbered 352 men.
According to the magazine Popular Mechanics of June 1916, p. 893 was she able to supply six submarines and ‘carries reserve crews to relieve under-water craft, is a floating hospital, repair ship, acts as a salvage boat, and by emptying its testing tube van be used as a floating dry dock. The testing tube, or dock is a steel cylinder of high tensile strength situated in the bowels of the vessel, partly below the normal water line, and having its entrance at the rear between portions of the stern, which is of the catamaran type. The open end of the testing tube may be closed by means of a globular caisson which fits into the opening tightly. The tube, after a submarine had been floated into it, is filled with water by a powerful pump which produces a pressure equivalent to that found at a depth of 200 or more feet. The pressure can be relieved almost instantly by opening the valves”. According to this magazine her cruising speed was 11.5 miles and her maximum speed 16 miles.’
