Maintenance and 
Replenishment Carrier

Ex HMS Ethalion, Ex HMS Mars


Pioneer was built by Vickers Armstrong, Barrow-in-Furness, laid down 2 December 1942 as HMS Ethalion, and renamed HMS Mars. She was launched 20 May 1944 and commissioned 8 February 1945 as HMS Pioneer.

HMS Pioneer 1945

Pioneer's wartime service was as a Colossus class maintenance support ship/carrier up until 1953. From February 1945 she was used as a maintenance support ship, and after VJ-Day was also resonsible for ditching obsolete aircraft off the Australian coast. She carried no operational aircraft but had workshops, cranes and guns fitted on her flightdeck.

HMS Pioneer ditching aircraft overboard into the sea near the Australian coast in 1945

Pioneer was stricken in 1954 and broken up at Inverkeithing from September 1954.

Battle Honours
None in World War II

No information on Captains.

Squadrons and Aircraft
None in WWII

Associations and Reunions
No information

Carrier name HMS Pioneer
Ex HMS Ethalion, and Ex HMS Mars.
Class Colossus
Type Light Fleet Aircraft Carrier
Ships in Class Colossus, Vengeance, Venerable, Pioneer, Glory, Ocean, Perseus, Theseus, Triumph, Warrior
Launched Laid down 2 December 1942. Launched 20 May 1944. Commissioned 8 February 1945 
Tonnage Displacement: 13,400 tons standard ; 18,330 tons full load
Engines Propulsion: Steam Turbines (4 Admiralty 3-drum boilers, 2 shafts, Parsons geared turbines), 40,000 shp.
Speed in Knots Speed: 25 knots
Armament Guns: 24 x 2 pdr AA ; 32 x 20 mm 
Crew Complement Compliment: 1300 (including air group)
Range  Range: 12,000 nmiles at 14 knots
Length (ft/inches) Dimensions: 630 pp, 650 wl, 695 oa x 80 x 23.5 feet
Beam (ft/inches)  
Draught (ft/inches)  
Flight Deck length (ft/inches)  
Flight Deck width (ft/inches)  
Number of aircraft carried Aircraft: 48
Fate of carrier Stricken 1954. Broken up.
Notes Scaled down version of Illustrious class but with a large aircraft compliment achieved by a lack of armour. Designed for rapid construction in merchant yards to make up for the shortfall in carriers but much more capable than escort carriers. Perseus and Pioneer were completed as maintenance carriers without catapults. After the war various units of the class were sold or reconstructed with angled decks or as helicopter carriers.

HMS Pioneer - Further information by British  
World Aircraft Carrier Lists and Photo Gallery - from 1913 to 2000. Naval History Information Center, Haze Gray & Underway   
Sturtivant, R & Ballance, T  (1994). 'The Squadrons of the Fleet Air Arm' Published by Air Britain (Historians) Ltd, 1994 ISBN: 0 85130 223 8

The World’s Warships 1941 by Francis E. McMurtrie (1944). Janes London 1941 1st ed. 

Jane's Fighting Ships of World War II by Francis E. McMurtrie (Editor)(1984). 320 pages. Crescent Books; ISBN: 0517679639

        Last Modified: 23-2-2001


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