''Ro-15'', originally named ''Submarine No. 24'', was an

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender ...

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

of the ''Kaichū'' II subclass. She was commissioned in 1921 and operated in the waters of

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

. She was stricken in 1933.

Design and description

The submarines of the ''Kaichu'' II sub-class were larger and had a greater range than the preceding ''Kaichu'' I subclass, but they had the same powerplant, so their greater size resulted in a loss of some speed.Gray, Randal, ed., ''Conway′s All the World′s Fighting Ships 1906–1921'', Annapolis, Maryland: Naval Institute Press, 1985, , p. 248. They also had a modified

conning tower A conning tower is a raised platform on a ship or submarine, often armored, from which an officer in charge can conn the vessel, controlling movements of the ship by giving orders to those responsible for the ship's engine, rudder, lines, and gro ...

, bow, and

stern The stern is the back or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite the bow, the foremost part of a ship. Ori ...

, and the stern was overhanging. They displaced surfaced and submerged. The submarines were long and had a

beam Beam may refer to: Streams of particles or energy *Light beam, or beam of light, a directional projection of light energy **Laser beam *Particle beam, a stream of charged or neutral particles **Charged particle beam, a spatially localized grou ...

of and a

draft Draft, The Draft, or Draught may refer to: Watercraft dimensions * Draft (hull), the distance from waterline to keel of a vessel * Draft (sail), degree of curvature in a sail * Air draft, distance from waterline to the highest point on a vessel ...

of . They had a diving depth of . For surface running, the submarines were powered by two Sulzer Mark II

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...

s, each driving one

propeller shaft A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to connect ...

. When submerged each propeller was driven by a

electric motor An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagneti ...

. They could reach on the surface and underwater. On the surface, they had a range of at ; submerged, they had a range of at . The submarines were armed with six

torpedo tube A torpedo tube is a cylindrical device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units (also referred to as torpedo launchers) installed aboa ...

s, four internal tubes in the bow and two external tubes mounted on the upper deck, and carried a total of ten Type 44

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, su ...

es. They were also armed with a single deck gun mounted aft of the

Construction and commissioning

''Ro-15'' was

laid down Laying the keel or laying down is the formal recognition of the start of a ship's construction. It is often marked with a ceremony attended by dignitaries from the shipbuilding company and the ultimate owners of the ship. Keel laying is one o ...

as ''Submarine No. 24'' on 12 June 1920 by the

Kure Naval Arsenal was one of four principal naval shipyards owned and operated by the Imperial Japanese Navy. History The Kure Naval District was established at Kure, Hiroshima in 1889, as the second of the naval districts responsible for the defense of the J ...

Kure is a port and major shipbuilding city situated on the Seto Inland Sea in Hiroshima Prefecture, Japan. With a strong industrial and naval heritage, Kure hosts the second-oldest naval dockyard in Japan and remains an important base for the Japan M ...

. Launched on 14 October 1920, she was completed and commissioned on 30 June 1921.

Service history

Upon commissioning, ''Submarine No. 24'' was attached to the

Kure Naval District was the second of four main administrative districts of the pre-war Imperial Japanese Navy. Its territory included the Seto Inland Sea, Inland Sea of Japan and the Pacific Ocean, Pacific coasts of southern Honshū from Wakayama prefecture, Wakayam ...

, to which she remained attached throughout her career. She was assigned to Submarine Division 15 — in which she spent the rest of her career — and to the Kure Defense Division on 1 July 1921. On 19 July 1921, a fire broke out in her

galley A galley is a type of ship that is propelled mainly by oars. The galley is characterized by its long, slender hull, shallow draft, and low freeboard (clearance between sea and gunwale). Virtually all types of galleys had sails that could be used ...

due to faulty

electrical wiring Electrical wiring is an electrical installation of cabling and associated devices such as switches, distribution boards, sockets, and light fittings in a structure. Wiring is subject to safety standards for design and installation. Allowable ...

and spread to the adjacent torpedo room.''Airship Investigation: Report of Col. Henry Breckenridge'', Washington, D.C.: Government Printing Office, 1933, p. 55.
/ref> She was flooded to extinguish it, but not before much of her interior was burned out. There were no casualties, and she was repaired and returned to service. Submarine Division 15 served in the Kure Defense Division until 1 December 1921 and again from 1 December 1922 to 1 December 1923. While cruising off Moji, Japan, on 29 July 1924, ''Submarine No. 24'' collided with a steamer, suffering no casualties.''Airship Investigation: Report of Col. Henry Breckenridge'', Washington, D.C.: Government Printing Office, 1933, p. 56.
/ref> ''Submarine No. 24'' was renamed ''Ro-15'' on 1 November 1924. On 1 December 1926, Submarine Division 15 began another assignment to the Kure Defense Division that lasted through the end of ''Ro-15''′s active service. ''Ro-15'' was stricken from the Navy list on 1 September 1933. She remained moored at Kure as a

hulk The Hulk is a superhero appearing in American comic books published by Marvel Comics. Created by writer Stan Lee and artist Jack Kirby, the character first appeared in the debut issue of ''The Incredible Hulk (comic book), The Incredible Hulk' ...

after that, and was renamed ''Training Hulk No. 3036'' on 7 March 1934. She served on training duties through the end of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

in August 1945, and was scrapped in September 1948.

Notes

References

*'', History of Pacific War Vol.17 I-Gō Submarines'',

Gakken is a Japanese publishing company founded in 1947 by Hideto Furuoka, which also produces educational toys. Their annual sales is reported at ¥ 90 billion ($789 million US). Gakken publishes educational books and magazines and produces other ...

(Japan), January 1998, *''Rekishi Gunzō, History of Pacific War Extra, "Perfect guide, The submarines of the Imperial Japanese Forces"'', Gakken (Japan), March 2005, *''The Maru Special, Japanese Naval Vessels No.43 Japanese Submarines III'', Ushio Shobō (Japan), September 1980, Book code 68343-44 *''The Maru Special, Japanese Naval Vessels No.132 Japanese Submarines I "Revised edition"'', Ushio Shobō (Japan), February 1988, Book code 68344-36 *''The Maru Special, Japanese Naval Vessels No.133 Japanese Submarines II "Revised edition"'', Ushio Shobō (Japan), March 1988, Book code 68344-37 *''The Maru Special, Japanese Naval Vessels No.135 Japanese Submarines IV'', Ushio Shobō (Japan), May 1988, Book code 68344-39 {{DEFAULTSORT:Ro-015 Ro-13-class submarines Kaichū type submarines Ships built by Kure Naval Arsenal 1920 ships Ship fires Japanese submarine accidents Maritime incidents in 1921 Maritime incidents in 1924