Special 1TL Type escort carrier

The Special 1TL Type (特1TL型, Toku 1TL gata) was a class of auxiliary escort carriers built for the Imperial Japanese Navy (IJN) during World War II. They were converted from Type 1TL tankers. It is also called the Shimane Maru (しまね丸) class in some western sources.

Shimane Maru, 28 July 1945
Class overview
Name	Special 1TL Type
Builders	Kawasaki Shipbuilding Corporation
Operators	Imperial Japanese Navy
Preceded by	Shinyo
Succeeded by	Special 2TL Type escort carrier
Built	1944–1945
In commission	1945
Planned	4
Completed	1
Cancelled	2
Lost	2
General characteristics
Type	Escort carrier
Tonnage	10,002 gross register tons (GRT)
Displacement	11,989 tonnes (11,800 long tons) (standard)
Length	160.5 m (527 ft) (o/a)
Beam	20 m (66 ft)
Draught	9.1 m (29 ft 10 in) (mean)
Installed power	2 boilers 8,600 shp (6,400 kW)
Propulsion	1 shaft; 1 steam turbine
Speed	18.5 knots (34.3 km/h; 21.3 mph)
Range	10,000 nmi (19,000 km; 12,000 mi) at 10 knots (19 km/h; 12 mph)
Sensors & processing systems	Type 3, Mark 1, Model 3 radar
Armament	2 × single 12 cm (4.7 in) guns 9 × triple, 25 × single 2.5 cm (1 in) AA guns
Aircraft carried	12

Although four conversions were reportedly considered, only two ships were launched, with just one being completed, and neither entered active service before being destroyed.

Design and description

The concept of the class was similar to British merchant aircraft carrier. The class consisted of two oil tankers of 10,002 gross register tons (GRT) that were modified by the Navy to provide minimal anti-submarine air cover for convoys going from Southeast Asia to the Japanese homeland. The conversion consisted of fitting a full-length flight deck, a small hangar, and a single elevator. An island and catapults were not installed. The only other change was the rerouting of the boiler uptakes to the aft starboard side where they discharged in a typical downward-facing funnel.

The ships had a length of 160.5 meters (526 ft 7 in) overall and 150 meters (492 ft 2 in) between perpendiculars. They had a beam of 20 meters (65 ft 7 in) at the waterline and a mean draft of 9.1 meters (29 ft 10 in). They displaced 11,989 metric tons (11,800 long tons) at standard load.^[1]

The Shimane Maru-class ships were fitted with a single geared steam turbine set with a total of 8,600 shaft horsepower (6,400 kW). It drove one propeller shaft using steam provided by two boilers. The ships had a designed speed of 18.5 knots (34.3 km/h; 21.3 mph) and a range of 10,000 nautical miles (19,000 km; 12,000 mi) at 10 knots (19 km/h; 12 mph).^[2]

The flight deck was 154.99 meters (508 ft 6 in) long and had a maximum width of 23.01 meters (75 ft 6 in).^[2] The hangar, built on top of the well deck, was served by a single elevator from the flight deck. It had a capacity of a dozen aircraft.^[1]

Ships

Ship	Builder	Laid down	Launched	Commissioned	Fate
Shimane Maru (しまね丸)	Kawasaki Heavy Industries Shipyard, Kobe	8 June 1944	17 December 1944	28 February 1945	Sunk 24 July 1945 by British aircraft at Shido Bay, Kagawa Prefecture[3] at position 34°20′10″N 134°10′15″E
Ōtakisan Maru (大瀧山丸)	Kawasaki Heavy Industries Shipyard, Kobe	18 September 1944	14 January 1945	Never	Construction was 70 % completed when she drifted onto a mine on 25 August 1945 and sank. Scrapped at Kobe, 1948
Daiju Maru (大邱丸)	Kawasaki Heavy Industries Shipyard, Kobe	18 December 1944	14 January 1945	Never Stopped in February 1945	Completed and sold to Iino Lines K.K. on 19 October 1949, renamed Ryūhō Maru (隆邦丸). Scrapped at Yokosuka, May 1964
Taisha Maru (大社丸)	-	Never	Never	Never	Cancelled in 1944

Photo

• 
  Shimane Maru in postwar
• 
  3rd sister Ryūhō Maru (ex.-Daiju Maru) in postwar