Capitan O'Brien-class submarine (1928)

Capitan Simpson
Class overview
Name	Capitan O'Brien class
Builders	Vickers
Operators	Chilean Navy
Built	1928–1929
In commission	1929–1958
Completed	3
Retired	3
General characteristics
Type	Submarine
Displacement	Surfaced - 1,540 long tons (1,560 t) Submerged - 2,020 long tons (2,050 t)
Length	260 ft (79 m) pp
Beam	28 ft (8.5 m)
Draught	13 ft 6 in (4.11 m)
Propulsion	2 shaft diesel-electric Vickers diesel engines: 2,750 bhp (2,050 kW) Electric motors: 1,300 hp (970 kW)
Speed	Surfaced: 15 knots (28 km/h; 17 mph) Submerged: 9 knots (17 km/h; 10 mph)
Complement	54
Armament	8 × 21 in (533 mm) torpedo tubes (6 bow, 2 stern 14 torpedoes) 1 × 4.7 in (119 mm)/45 deck gun

The Capitan O'Brien class were three submarines built for the Chilean Navy in the late 1920s. Designed and built in the United Kingdom, they were a modified design of the contemporary British Odin-class submarines. The lead boat, Capitan O'Brien, was launched on 2 October 1928 and the other two on 15 January 1929. All three submarines entered service in 1929. The three vessels remained in service until being discarded in 1957–1958.

The Capitan O'Brien class were three submarines constructed to a modified design based on the British Royal Navy's Odin class.^[1] The Odin class was the Royal Navy's leading submarine design in the post-World War I era, equipped with strengthened pressure hulls and fuel carried in the ballast tanks to improve rapid diving. They had extended surface range.^[2] The Capitan O'Briens measured 260 feet (79 m) long between perpendiculars with a beam of 28 ft (8.5 m) and a draught of 13 ft 6 in (4.11 m). They had a displacement of 1,540 long tons (1,560 t) while surfaced and 2,020 long tons (2,050 t) submerged.^[1] The submarines were propelled by two shafts powered by two Vickers diesel engines creating 2,750 brake horsepower (2,050 kW) while surfaced and two electric motors creating 1,300 hp (970 kW) while submerged. This gave them a maximum speed of 15 knots (28 km/h; 17 mph) surfaced and 9 knots (17 km/h; 10 mph) submerged.^[1] The builder's photograph of Capitan Simpson gives the dimensions as 272 feet 9 inches (83.1 m) long overall with a beam of 27 feet 6 inches (8.4 m) and a draught of 16 feet 6 inches (5.0 m) with a surface speed of 15 knots and 9.5 knots (17.6 km/h; 10.9 mph) submerged.^[3]

The Capitan O'Briens had a large conning tower that stretched one-third of the deck and mounted the 4.7-inch (119 mm)/45 deck gun in a turret. The submarines were also armed with eight 21 in (533 mm) torpedo tubes, with six located in the bow and two in the stern. The subs carried 14 torpedoes. Each submarine had a complement of 54 personnel.^[1]

• Cocker, Maurice (2008). Royal Navy Submarines: 1901 to the Present Day. Barnsley, UK: Pen and Sword Books Ltd. ISBN 978-1-84415-733-4.
• Scheina, Robert L. (1980). "Chile". In Chesneau, Roger (ed.). Conway's All the World's Fighting Ships 1922–1946. Greenwich, UK: Conway Maritime Press. pp. 422–423. ISBN 0-85177-146-7.
• Vickers-Armstrongs Limited (1930). The Activities of Vickers-Armstrongs Limited, naval construction works, Barrow-in-Furness. London: Vickers-Armstrongs Ltd. OCLC 13323843.