Military Wiki
SS Empire Bison
Name: West Cawthon (1919-40)
Empire Bison (1940)
Owner: United States Shipping Board (1919-20)
Green Star Steamship Corporation (1921-23)
Imperial Shipping Co Ltd (1923-26)
American-South African Line Inc (1926-40)
Ministry of War Transport (1940)
Operator: Sir R Ropner & Co Ltd (1940)
Port of registry: United States New York (1919-40)
United Kingdom London (1940)
Builder: Southwestern Shipbuilding Co, San Pedro California.
Yard number: 6
Launched: 16 April 1919
Completed: June 1919
Out of service: 1 November 1940
Identification: US Official Number 218322 (1919-40)
UK Official Number 167628 (1940)
Code Letters LRPW (1930 -34)
ICS Lima.svgICS Romeo.svgICS Papa.svgICS Whiskey.svg
Code Letters KILZ (1934-40)
ICS Kilo.svgICS India.svgICS Lima.svgICS Zulu.svg
Code Letters GTQS (1940)
ICS Golf.svgICS Tango.svgICS Quebec.svgICS Sierra.svg
Fate: Torpedoed and sunk by U-124
General characteristics
Tonnage: 5,612 GRT
3,492 NRT
Length: 410 ft 5 in (125.10 m)
Beam: 54 ft 2 in (16.51 m)
Depth: 27 ft 6 in (8.38 m)
Propulsion: Triple expansion steam engine
Speed: 10.5 knots (19.4 km/h; 12.1 mph)
Crew: 35

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Empire Bison was a 5,912 GRT cargo ship built in 1919 for the United States Shipping Board (USSB) as West Cawthon. In 1940 she was transferred to the Ministry of War Transport (MoWT) and renamed Empire Bison. She was torpedoed and sunk by U-124 on 1 November 1940.


West Cawthon was a Design 1019 ship.[1] She was built by Southwestern Shipbuilding Co, San Pedro California for the USSB.[2] She was yard number 6 and was launched on 16 April 1919 with completion in June.[1]


West Cawthon was owned by the USSB. In 1920 she was sold to the Green Star Steamship Co, New York. In 1921 she was sold to Imperial Shipping Co, New York, and was sold back the USSB in 1923. In 1926 West Cawthon was sold to the American-South African Line Inc.[3] Her port of registry was New York.[4] She operated between the United States and Africa.[5] During the Second World War, West Cawthon was a member of a number of convoys.

HX 58

Convoy HX 58 departed Halifax, Nova Scotia on 15 July 1940 and arrived at Liverpool on 31 July. West Cawthon was carrying a cargo of steel and general cargo bound for Manchester. She was notified in the Advanced Sailing Telegram as carrying ammunition.[6]

In 1940, West Cawthon was sold the MoWT and renamed Empire Bison.[2] Her port of registry was London.[7] Empire Bison was a member of a number of convoys.

HX 82

Convoy HX 82 departed Halifax on 20 October 1940 and arrived at Liverpool on 6 November.[8] The weather for the convoy was extremely bad and on 23 October in a westerly gale force 8-9 the convoy hove to. As Empire Bison tried to come about a man was washed overboard. Empire Bison and four other ships were forced to continue without the convoy. In the continuing bad weather contact with the convoy and the four other ships was lost. Empire Bison was torpedoed by U-124 and sunk at 59°30′N 17°40′W / 59.5°N 17.667°W / 59.5; -17.667Coordinates: 59°30′N 17°40′W / 59.5°N 17.667°W / 59.5; -17.667 on 1 November 1940 at 05:13.[9] There were only four survivors, 38 crew and passengers perished. At the time of her loss, Empire Bison was carrying a cargo of 6,067 long tons (6,164 t) of scrap metal and 94 lorries. The survivors were picked up by the Danish steamship Olga S and landed at Gourock, Renfrewshire.[3] Those lost on Empire Bison are commemorated at the Tower Hill Memorial, London.[10]

Official Numbers and Code Letters

Official Numbers were a forerunner to IMO Numbers. West Cawthon had the US Official Number 218322 and the Code Letters LRPW.[4] In 1934, her Code Letters were changed to KILZ.[11] Empire Bison had the UK Official Number 167628 and used the Code Letters GTQS.[7]


The ship had a triple expansion steam engine which had cylinders of 24 12 inches (62 cm), 41 12 inches (105 cm) and 72 inches (180 cm) diameter by 48 inches (120 cm) stroke. The engine was built by the Llewellyn Iron Works, Los Angeles. It developed 349 horsepower (260 kW).[4] She was capable of 10.5 knots (19.4 km/h; 12.1 mph).[1]


  1. 1.0 1.1 1.2 "West Cawthon (2218322)". Miramar Ship Index. Retrieved 9 November 2009.  (subscription required)
  2. 2.0 2.1 Mitchell, W H; Sawyer, L A (1995). The Empire Ships. London, New York, Hamburg, Hong Kong: Lloyd's of London Press Ltd. ISBN 1-85044-275-4. 
  3. 3.0 3.1 "Empire Bison". Retrieved 9 November 2009. 
  4. 4.0 4.1 4.2 "Lloyd's Register, Steamer & Motorships" (pdf). Retrieved 9 November 2009. 
  5. "Farrell Lines / American South African Line". Retrieved 9 November 2009. 
  6. "Convoy HX 58". Retrieved November 2009. 
  7. 7.0 7.1 "Lloyd's Register, Steamer & Motorships" (pdf). Retrieved 9 November 2009. 
  8. "Convoy HX 82". Retrieved November 2009. 
  9. J B Carlton Survivor Report 14 December 1940
  10. Watson, Brian. "WW2 Memorial Ship Index A-F". Retrieved 20 May 2011. 
  11. "Lloyd's Register, Navires a Vapeur et a Moteurs" (pdf). Plimsoll Ship Data. Retrieved 9 November 2009. 

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