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Amphibious Encyclopedia · Military amphibians

Alvis Stalwart

The Alvis Stalwart is a British six-wheel-drive amphibious truck, officially the High Mobility Load Carrier, built by Alvis of Coventry from the early 1960s until 1971 [1][2]. It could carry 5 metric tons across rough country and swim rivers using two water jets, and it served the British Army, mostly in West Germany, until the early 1990s [2][3].

  • Military amphibians
  • 1963 to 1993
  • United Kingdom

History

Alvis developed the Stalwart as a private venture, without a government order, using the six-wheel layout of its FV600 family of armored vehicles, which included the Saracen, the Saladin and the Salamander airfield crash tender [1][2]. The first prototype, PV1, was finished in December 1959 on a Salamander chassis [2]. The aim was a truck that could keep armored units in West Germany supplied with fuel, ammunition and stores [2].

PV2 of 1961 was the first fully amphibious version, with a sealed cab and water-jet drive [2]. Accounts differ on when it was first demonstrated in Sweden: September 1961 in one history, and March 1962 near Vaxholm according to the Alvis Archive [2][4]. The War Office ordered 125 Mk 1 vehicles (FV620) in August 1962, and the first entered service in 1963 [2]. The improved Mk 2 (FV622), with a revised cab, better brakes and an internal winch, followed in early 1966, and production ended in April 1971 [2].

Most Stalwarts served with the British Army of the Rhine, supplying artillery regiments, engineer squadrons and armored brigades, and they were usually crewed by the Royal Corps of Transport [2]. Mk 2 versions included the FV623 artillery limber with a crane, about 269 of which were built, and about 60 FV624 fitters' vehicles for REME [1][2]. Of the 956 Mk 2s, the British Army took about 930 [1][4]. The Army removed the amphibious equipment in the early 1980s, declared the type obsolete in January 1992 and sold the last vehicles in 1993 [2].

Swedish and other users

Sweden's coastal artillery was the main foreign military user and named the vehicle Amfibiebil 101 [4][6]. It received two pre-production prototypes in 1962, six Mk 1s in 1965 and about 18 Mk 2s in 1967, and a Swedish museum record puts the total at 24 [4][6]. The Swedes used them to tow radar trailers out to coastal islands, among other jobs, and sold the last ones in 1985 [4]. Austria bought three for flood relief, and Sri Lanka bought five refurbished ex-Swedish Mk 2s in 1985 [1][2].

Design and how it works

The Stalwart has six large wheels, all permanently driven, with independent double-wishbone and torsion-bar suspension at each wheel [1][2]. A Rolls-Royce B81 eight-cylinder gasoline engine of about 6.5 liters and 220 hp (164 kW) drove through a five-speed gearbox, and the truck could reach 40 mph (64 km/h) on roads [1][2]. Its steel hull is 20 ft 10 in (6.35 m) long and 8 ft 7 in (2.62 m) wide [1][3].

On water the hull floats and two Dowty water jets, driven from the engine, push and steer it [2][3]. A Mk 2 swam at about 10 km/h (6 mph) unladen [2]. Because of its low freeboard, the swimming load was limited to 3 tons, against 5 metric tons on land [2]. The wheels on each side were geared together with no axle differentials, so long drives on hard roads caused transmission wind-up that damaged drive parts and tires [1][2]. An Imperial War Museums film records Mk 2 trials in July 1968 at the Amphibious Experimental Establishment in Devon, where a DUKW stood by and at times winched the Stalwart free [5].

Legacy

The Stalwart had no direct amphibious successor; conventional trucks such as the Bedford TM and, from 1990, the DROPS load-handling system took over its supply role [2]. Civilian users included BP, for oil-spill response, and Bangkok airport, as a rescue vehicle [1][2]. Many survivors went to collectors, and examples are shown in museums in Britain, Sweden and Germany, including the Norfolk Tank Museum, whose vehicle's water-jet system has been disabled [1][3][4].

Sources

  1. Alvis Stalwart, Wikipedia. en.wikipedia.org/wiki/Alvis_Stalwart
  2. Alvis Stalwart Amphibious Load Carrier, ThinkDefence (2026-11-04). www.thinkdefence.co.uk/docs/alvis-stalwart-amphibious-load-carrier
  3. Stalwart H.M.L.C. FV620, Norfolk Tank Museum. norfolktankmuseum.co.uk/?p=181
  4. Sweden and the Stalwart (Mark Ellis), Alvis Archive. alvisarchive.com/fighting-vehicles/stalwart/sweden-and-the-stalwart
  5. Trials of Alvis Stalwart Mark II, Devon, July 1968 (film BFM 524), Imperial War Museums. film.iwmcollections.org.uk/record/16372
  6. Amfibiebil 101, Museum för rörligt kustartilleri, via DigitaltMuseum (2019-01-25). digitaltmuseum.se/021018209932/amfibiebil-101

Last reviewed November 2026. Spotted something to correct or add? Tell us and include a source.

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WaterCar has designed and built amphibious vehicles in Southern California for more than 25 years. We keep this encyclopedia so anyone curious about vehicles that cross between land and water has one place to start, with the sources listed for every fact.

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