Osetr-class submarine

The Osetr class were a group of submarines built for the Imperial Russian Navy during the Russo–Japanese War. The boats were ordered in the 1904 emergency programme. The boats were designed by American engineer Simon Lake and had wheels fitted for moving around on the sea bed as well as wet/dry chambers for divers. Osetr was the former Protector sold by Lake to the Russians and re-assembled in Russia. The diving depth was around 30 metres (98 ft).

Russian submarine Sig
Class overview
Name	Osetr class
Builders	Libau Arsenal, Latvia
Operators	Imperial Russian Navy
In commission	1905–1913
Completed	6
Retired	6
General characteristics
Type	Submarine
Displacement	153 tons surfaced 187 tons submerged
Length	22 m (72 ft 2 in)
Beam	3.6 m (11 ft 10 in)
Draught	3.7 m (12 ft 2 in)
Propulsion	2 shafts: petrol / electric 2 × 120 hp (89 kW) / 2 x 65 hp (48 kW)
Speed	8.5 knots (15.7 km/h; 9.8 mph) surfaced 4.5 knots (8.3 km/h; 5.2 mph) submerged
Complement	12 (including 2 officers)
Armament	3 × 18-inch torpedo tubes (2 bow, 1 stern)