FV433, 105mm, Field Artillery, Self-Propelled "Abbot" is the self-propelled artillery, or more specifically self-propelled gun, variant of the British ArmyFV430 series of armoured fighting vehicles, using much of the chassis of the FV430 but with a fully rotating turret at the rear housing the 105 mm gun and given the vehicle designation of FV433. Designed as a Sexton replacement, its correct designation was "Gun Equipment 105mm L109 "; L109 was little used, probably to avoid confusion with the 155 mm M109 howitzer that entered UK service at about the same time. The name "Abbot" continued the Second World War style of naming self-propelled artillery after ecclesiastical titles. The FV433 used a different configuration of power pack from other vehicles in the FV430 series.
Development
Ammunition
A completely new ammunition family, comprising shells, fuzes and cartridges, was designed for Abbot's L13 gun, designated 105 mm Field. Compared to US 105 mm M1 type ammunition, it uses electrical instead of percussion primers, and has longer shells. The widely used US M1 type round was called "105 mm How" in UK service. The 105 mm Fd came in two marks, both separate loading. The 105 mm Fd Mk 1 was used initially, it had a UK-produced 105 mm How shell, mostly US pattern fuzes and reduced charge 105 mm Fd cartridges with their electrical primers. The Mark 2 adopted a new projectile design including an improved lethality HE shell and full charge cartridges. Its shell types include HE, Smoke, Coloured Marker, Illuminating, and HESH for direct fire against enemy armoured vehicles. Direct Action, Controlled Variable Time and Mechanical Time fuzes were available for HE and Coloured Marker shells. Initially, there were three cartridges. Sub-zones 1 and 2 were only used to provide short range in high angle fire, and were soon replaced by a plastic spoiler slipped over the shell ogive. Normal cartridge gave charges 1–5, each bag being a different colour in accordance with established UK practice, Mk 1 normal cartridge only went to charge 4. Both marks had charge Super, a single charge cartridge, although the charge was reduced in Mk 1. Charges 5 and Super used extended "bags" that projected beyond the metal cartridge case. The 105 mm Fd uses double base propellants designated N in UK service instead of the single based FNH propellants favoured by the US. The 105 mm Fd Mk 2 is still used with L118 Light Gun.
Gun
Maximum range with 105 mm Fd Mk 1 ammunition was 15 km, the Mk 2 gave 17.4 km. Maximum rate of fire was 6–8 rounds per minute. The gun was able to elevate to 70 degrees and depress to -5 degrees, sufficient to engage enemy AFVs if necessary. Traverse and shell ramming were powered by electrical servo mechanisms, elevation and cartridge ramming were by hand. Due to the number of charges and its compact turret, the Abbot did not have calibrating sights. Instead, the sight mount had both Tangent Elevation and Angle of Sight Scales and a separate Gun Rule to convert range into TE, corrected for the muzzle velocity variation from standard. The dial sight had all scales internal, illuminated and viewed through a single eyepiece.
Communications
The Abbot was fitted with both line and radio Larkspur B48, then Clansman UK/PRC 352) communications to its battery command post, which used the Apparatus Loud Speaking No. 23, this enabled the gun No. 1 to acknowledge his fire orders merely by clicking his pressel switch. Initially, it also used induction loop communications for the turret and external crew. Shortly after the Field Artillery Computer Equipment entered service in the early 1970s, the Gun Rule was removed and the Artillery Weapon Data Transmission System installed. AWDATS displayed firing data transmitted from FACE in the battery command post via either line or radio.
Mobility
The Abbot was able to swim across water, having a flotation screen fixed around the hull that was raised to provide buoyancy. The action of the tracks was sufficient to drive it forward at about 3 knots. Each Abbot was supported by a fully amphibious Stalwart Mk 2 High Mobility Load Carrier that carried additional ammunition.
Service history
British Army Abbots were replaced by the AS-90 self-propelled gun in the mid 1990s. It is still in service with the Indian Army, though they are looking for a replacement.. No sources refer to Abbots ever being used in combat.
A simplified Value Engineered Abbot without flotation screen, NBC defence equipment, power traverse, elevation or loading, a simplified dial sight and communications fit was exported to India. A small number were purchased by the UK for use at the British Army Training Unit Suffield in Alberta, Canada. A SPAAG version using an unmodified chassis with an alternate turret mounting two guns was prototyped as the "Falcon" but limited ammunition capacity led to its cancellation. The Abbot's L13 105mm gun has been reproduced as a towed howitzer on a new carriage for the Indian Army.
Operators
British Army - 146 received for use by Royal Artillery regiments
An Abbott appears at the very end of the 2007 film, The Mist as the first rescue vehicle in the military convoy. The comedian Ross Noble revealed on the 3 July 2011 edition of BBC motoring show Top Gear that he owns and operates an FV433. He also stated that the vehicle is exempt from the London congestion charge. An Abbot is featured in the February 2018 fourth episode of series five of the tv showEndeavour.
