In the late 1950s, the United Kingdom was looking for a new Self-Propelled Gun (SPG). It was envisioned that this would replace the Ram-based Sexton, a Second World War-era 25-Pounder gun-armed SPG that was still in service with the Royal Artillery. It was also planned that it would somewhat replace the 25-Pounder gun in general, as the towed version was also still in service. Even so, there were some developments with 25-pounder armed SPGs, such as the Centurion-based FV3805. This was unsuccessful, however.
A 105 mm gun would be developed to replace the 25-Pounder. For ease of production, it was decided that this new SPG would be based on the FV432 ‘Trojan’ Armoured Personnel Carrier, then coming into service. The SPG would receive the designation ‘FV433’ and would be designed and constructed by Vickers. They would go on and build a total of 234 vehicles, the majority of which would see service with the British Army, though a few simpler, ‘Value Engineered’ versions would also be designed and sold to the Indian Army.
The FV433 would be the last Self-Propelled Gun to be named – in British tradition – after a religious title. In this case, ‘Abbot’. An Abbot is a man in charge of an abbey of monks. As well as the above mentioned Sexton, there were others named in this way, such as the Deacon, Bishop, and M7 ‘Priest’.
Foundation, The FV432
The FV432 Armoured Personnel Carrier (APC) was a small vehicle at 17 feet 2 inches (5.25 m) long, 9 feet 2 inches (2.8 m) wide and 7 feet 5 inches (2.28 m) tall. It had a two-man crew (Commander & Driver) and had the ability to carry up to ten troops.
The FV432 weighed 15 tons (15.3 tonnes) and was powered by the 240 hp Rolls-Royce K60 multi-fuel engine. This gave it a top speed of 44 mph (70 km/h). A torsion-bar suspension gave the vehicle a smooth and comfortable ride. It had five road-wheels per-side, with the drive sprocket at the front and the idler at the rear.
The Abbot would utilize the exact same powertrain and suspension as the FV432 APC. This SPG was one of many variants that would be born from the FV432, or ‘Battle Taxi’, as it would come to be known throughout its service life.
Development of the FV433 took place between 1958 and 1960 at the Fighting Vehicle Research and Development Establishment (FVRDE) located in Chertsey, Surrey. Basing a vehicle on an existing model has a number of benefits: It allows for a commonality of parts making maintenance easier, but also allows possible operators to familiarize themselves with the particulars of the vehicle when it comes to driving, for example. It also lowers costs and simplifies the logistical train required.
Vickers came up with a design for this new Self-Propelled Gun. The aim was to create a small, mobile SPG that was flexible and could be deployed quickly. It would be armed with a large caliber, quick-firing gun to enable saturation of a target in a short time.
They would utilize as many components from the FV432 APC as possible for the hull. For the gun, the new 105 mm L13A1 gun was chosen although at the time there were several contenders to be the new standard artillery caliber. This was placed in a turret towards the rear of the vehicle. As in the FV432, the engine and transmission were located at the front of the vehicle. A unique feature to the ‘Abbot’ compared to other SPG’s of the time was the fact that it was amphibious. This was possible via a flotation screen, like those used on the famous Sherman DD tanks of D-Day. The SPG would also have Nuclear, Biological & Chemical (NBC) protection.
By 1961, Vickers had produced 12 prototypes of the FV433. Six of these were fitted with the Rolls-Royce B81 petrol engine before the multi-fuel K60 of the FV432 was chosen as the production standard. This was a 6-cylinder horizontally opposed engine. These engines consist of two pistons per cylinder, working against each other in opposite directions. The idea behind multi-fuel engines was that in an emergency, the engine could run on either petrol (gasoline), diesel, or other fuel types. A similar, although less successful and more troublesome, engine was installed on the FV4201 Chieftain.
Vickers began full-scale production of the FV433 Abbot at their Elswick facility in Newcastle-upon-Tyne in 1964.
Sharing the same hull as the FV432 APC, the Abbot gained similar dimensions at 19 feet 2 inches (5.8 m) long, 8 feet 8 inches (2.6 m) wide, and 8 feet 9 inches (2.7 m) high. The vehicle would weigh around 16 tons (16.2 tonnes). It utilized the same running gear and track.
The general shape of the hull was also similar, small and boxy, but sloped down towards the front. This sloping front housed the engine, gearbox, transmission, and fuel tanks. The driver was also located at the front, to the right. On the front of the hull, there were four large headlights mounted in two double-light units (the prototype only had two lights).
On the rear of the hull, there was a large hatch that opened out to the right. This hatch was used while the gun was in operation. It allowed the crew easy access to the fighting compartment and provided ventilation. It would also provide an opening to discard spent cartridges, instead of letting them pile up in the confined space of the turret. Obviously, this door would not be used in hazardous situations. There was stowage above the door for some pioneer tools.
The exhaust was located on the left of the hull. On the prototypes, this was placed above the flotation screen. On the production model, this was moved to between the flotation screen and top of the fender.
As mentioned above, the ‘Abbot’ was equipped with a flotation screen. This allowed the SPG to negotiate through calm waterways. Propulsion was provided by the revolution of the tracks, as was steering. When not in use, the screen collapsed onto the hull. On the prototypes, this sloped from the back to the front of the hull as one piece. On production models, this was adapted so it followed the shape of the hull. In later years of its use in service, however, this screen was removed.
The turret was capable of 360-degree horizontal rotation, allowing for great flexibility in fire-missions. It was rather small and took the shape of a non-equal octagon. It was also slightly frustoconical, narrow down towards the roof, meaning all panels sloped back a few degrees. The right turret cheek had a triangular bulge incorporated to make way for the gunnery equipment inside the turret. The turret face had a bolted-on reinforcing plate around the gun slot. At the top of this, there was a semi-circular cut-out that allowed the gun to reach maximum elevation. There were hatches at the left and right rear for the commander (right) and loader (left). There was also a small ‘ammunition supply’ hatch on the rear of the turret. When open, it revealed a tray with grooves for two 105 mm rounds.
The outer circumference of the turret was covered in stowage. On the left and right turret sides, there were fastening points that would allow the attachment of large ‘soft’ bins. Smaller boxes were scattered around, with a shovel being stored on the right turret cheek. On the right rear corner, the large ventilation unit for the NBC system was installed. On the left rear corner, a wire reel was hung. This was a spool of telephone wire that was carried by most British tanks at the time. It would be used in bivouac areas when the tanks were in their defensive positions. The wire was hooked up to each tank and allowed them to discreetly communicate without broadcasting their positions via radio comms.
The driver was located at the front right corner of the hull. He was provided with a two-part hatch cover which opened to the left and right. For closed-down driving, he was provided with a single wide-angle periscope built into the hull roof just in front of the driver’s hatch. This periscope was even equipped with twin wipers.
Three crew members were stationed in the turret. These were the Commander, Gunner – also known as the Gun Layer, and Loader. The Gunner was located at the right front of the turret and was without a hatch. The Commander was positioned directly behind him. He had override controls for the rotation of the turret. This allowed him to quickly lay the gun onto a target in an emergency. The commander sat under a rotating vision cupola with a hatch that opened up and rear and three vision periscopes. The Loader was positioned in the left rear corner of the turret, had a basic one-piece hatch over his head and also performed radio operator duties.
Although the vehicle technically had a six-man crew, only four were present on the tank at all times. There was not enough room for all six. The Driver, Commander, Gunner, and the Radio-Operator/Loader would travel with the SPG. The other two men were the Ammunition Handler and the Second in Command, who was responsible for correct ammunition preparation (setting charges and fuses correctly). These men would travel in an accompanying support vehicle and would join the rest of the crew upon reaching the designated firing position.
The ‘Abbot’ was only lightly armored, as it was not intended to combat enemies head-on. Armor on the hull consisted of 12 mm (0.47 inches) on the front and sides, 10 mm (0.39 inches) at the rear and 6 mm (0.23 inches) on the floor. Armor on the turret was 10 mm around the sides and 12 mm on the roof. This armor was simply intended to protect the vehicle’s occupants from shrapnel and small arms fire.
The 105 mm L13A1 was a brand new design built by the Royal Ordnance Factory (ROF). It was not only intended as the weapon of choice for Self-Propelled Guns but also as the main-stay towed piece of British artillery units. The 105 mm (4.1-inch) caliber was chosen after detailed examination showed it had an effective blend of weight, lethality and range.
The gun was 37 calibers (3.8 meters) long with a double-baffle muzzle break at the end and a fume extractor halfway down the length. The gun uses a semi-automatic, vertically sliding breech (a semi-automatic breach means the spent rounds are not ejected automatically after firing, but the breech closes automatically when loading) and is mounted in a ring-type cradle with twin hydraulic buffers. It was also equipped with a single hydro-pneumatic recuperator. The gun was mounted in the 360-degree-capable turret and had an elevation range of +70 to -5 degrees. Elevation was tended by hand wheels, although the rotation of the turret was powered. There was a travel lock located on the front of the hull, just off to the left of the centerline.
For indirect-fire, the gun was laid via a periscope that protrudes from the turret roof and was protected by a small armored cupola. Thanks to its fully rotatable turret and wide elevation range, the ‘Abbot’ was also capable of direct-fire at enemy vehicles. This was an ability requested by Gunners themselves. For this, a telescopic sight was provided. It should be noted, however, that the ‘Abbot’s’ primary role was to provide fire-support. It was not designed to be in the front line or engage in combat with tanks. They were designed to fire shells over the heads of friendly troops from long range.
Because of the amount of ammunition carried and the compact nature of the turret, the FV433 did not have calibrating sights. To overcome this, the gun mount had both Tangent Elevation (TE) and Angle of Sight (AOS) scales with a separate gun rule to convert the range into TE in mils, with corrections made for the ammunition type in use. The single eye-piece sight used internal, illuminated scales.
Secondary armament consisted of a light machine gun installed on the Commander’s cupola. In the early years of the ‘Abbot’s’ service, this would have been the L4 7.62 Light Machine Gun – an upgraded version of the faithful Bren Gun of WW2. In later years, this was replaced by the General-Purpose Machine Gun, or ‘GPMG’, also chambered in 7.62 mm (.30 Cal). The FV433 was also equipped with smoke grenade launchers, three-per turret cheek.
A wide range of ammunition was available to the ‘Abbot’. For indirect-fire, this consisted of L31 High Explosive (HE), L37, L38 & L45 Smoke, and L43 Illumination. For direct fire, the Abbot was equipped with L42 High-Explosive Squash Head (HESH) shells and the L31 HE shell could also be used in the direct-fire role. The ammunition was two-part, meaning the projectile was separate from the propellant case, and that they were loaded separately. In this case, the projectile was loaded with the assistance of an electrically powered rammer, while the propellant was inserted by hand. The propellant for the 105mm gun was placed in brass cartridge cases. The primers were electrically triggered, rather than mechanically via a firing-pin. The propellant in the cases was contained in specific amounts in marked bags. A total of eight could be used in a cartridge; the more bags, the greater the range. There were, however, two cartridge types – supercharged and standard. The supercharged cartridge produced the greatest range and was filled with a much more potent charge. The standard cartridge contained 1-5 charge bags of equal size. There were also two lower-power charges known as ‘Sub zone A & B’. These were used in standard cartridge cases emptied of the standard charges. A maximum of 42 rounds were carried aboard the ‘Abbot’ (36 HE and 6 HESH). In normal operations, however, only 40 rounds were usually carried (32 HE and 6 HESH). The rounds were stored around the inside of the turret and the hull.
The ‘Abbot’ had an extremely high rate of fire, so much so that three ‘Abbots’ could saturate a target with about half a tonne (453 kgs, 6-8 rounds) of shells per minute. This rate of fire was achieved thanks to the rotating turret and the semi-automatic breech with a powered rammer. At the time of its introduction, the ‘Abbot’ was unrivaled when it came to its blend of firepower, accuracy, and range covered. Its rotating turret gave it the ability to engage any target, in any direction without the need to reposition the hull. The high elevation angle of the gun also gave the ability to engage targets behind the steepest covers. It was able to engage targets accurately up to its maximum firing range of 19,000 yards (11 mi, 17.3 km). The 105 mm gun had a service life of 10,000 rounds.
The ‘Value Engineered’ ‘Abbot’ (VEA)
In 1965, Vickers presented the ‘Abbot’ to the Indian military. The Indians were impressed with everything about the SPG, apart from its price tag. This resulted in a full-scale investigation by the ‘Value Engineering’ Department of the Vickers Armament Division. Simply put, the Value Engineering process produces a cheaper vehicle, without impact to its tactical capability. The first ‘Value Engineered’ ‘Abbot’ was produced in 1967 and was taken to India for demonstration the same year.
The VEA was different from the standard Abbot in the following ways:
- The flotation screen was removed
- The engine was exchanged for the Rolls-Royce K60 Mark G/1, a variant of the standard engine that only ran on diesel
- No rubber pads on the tracks
- No power traverse – turret traverse and gun elevation/depression were manual
- No electric rammer
- The armored cover of the roof-mounted gun sight was replaced by a canvas one, sights were replaced with a German model
- The Commander’s cupola did not rotate and was only equipped with one periscope.
- No smoke launchers or roof-mounted machine gun
- Reduced external stowage
The Indian Army was happier with this cheaper ‘Abbot’, so much so that they accepted the vehicle for service. From 1967 onwards, a total of 88 VEAs were built. Twenty of these went to the British Army, specifically to the British Army Training Unit Suffield (BATUS) in Canada, as training vehicles. The remaining 68 SPG’s were sent to the Indian Army, where they were operated well into the late-1990’s.
The VEA was not the only vehicle that Vickers sold to the Indian Army. In the mid-1960’s, Vickers developed a main battle tank (MBT) which they called the ‘Vickers Main Battle Tank’. While it never entered service in the UK, the Indian Military were extremely happy with it, becoming India’s first MBT, and was named the ‘Vijayanta’.
Developed in the late-1960s, the ‘Falcon’ was a Self-Propelled Anti-Aircraft Gun (SPAAG) system based on the ‘Abbot. It utilized the VEA’s hull, but could easily be upgraded to standard ‘Abbot’ configuration (re-application of flotation screen, headlights, etcetera). A new turret was designed for the ‘Falcon’, which was armed with two Hispano Suiza HSS 831L 30 mm auto-cannons. These cannons utilized the same ammunition as the British-made 30 mm Rarden cannon, as used on the Scimitar and Fox light vehicles. The vehicle was operated by a crew of three, consisting of a Commander, Gunner, and Driver. Though designed to combat aircraft, it was also capable of combating lightly armored vehicles.
Despite extremely successful tests in the early-1970’s and favorable opinions from military officials, the ‘Falcon’ never entered service. This was largely due to a rather small ammunition capacity, caused by the small and cramped nature of the FV430-type hull.
The ‘Abbot’ entered service in 1965, alongside around 140 M109 Howitzers purchased from the United States. The 3rd Battalion Royal Horse Artillery (3 RHA) became the first regiment to be equipped with it. The ‘Abbot’ spent almost all of its service life with British forces stationed in Germany. Its small size and good mobility allowed it to be deployed anywhere in a very short time, should the Cold War have turned hot. The ‘Abbots’ were placed in Field Regiments supporting Armoured Brigades, this would have been about 8 Regiments (142+) guns in the British Army of the Rhine (BAOR).
The ‘Abbot’ was an extremely reliable vehicle and was easy to maintain. As a result, the ‘Abbot’ became loved by its crews, despite it being very cramped internally. To describe how cramped it was inside, fellow amateur tank researcher and enthusiast, Rita Cardoso Sobral, has said “I am only 5′ 3” and it was nearly impossible for me to get in/out.”
The ‘Abbot’ served the British Army for 28 years before it began to be replaced by the 155 mm gun-armed AS-90 in 1993.
Thanks to its reliability, many ‘Abbots’ still survive and are operated by private owners and/or companies. They are relatively easy to come by for private purchase at a relatively good price, and many can be found in museums across the world. These include the Wight Military and Heritage Museum, Isle of Wight (UK) and the Australian Armour and Artillery Museum (AAAM), Queensland, Australia, among many others. Many tank-driving attractions also feature ‘Abbots’ as part of their fleet. Such places include ‘Tanks-Alot’, based in Brackley, England, and ‘Drive A Tank’ based in Minnesota, USA.
One of the best examples of a private company using the ‘Abbot’ is the ‘Grenade’ sports nutrition company. In the UK, they use an ‘Abbot’ covered in their brand logo as an advertisement. As of 2019, they have also started selling authentic ‘Abbot’s’, done up in ‘Grenade’ colors on their website for the price of £75,000 ($94,000). See HERE.
The ‘Abbot’ was an attempt by the British Military to create an effective SPG on a common platform. In doing so, it became one of the most successful Self-Propelled Gun platforms used by the UK, largely due to its firepower, flexibility, and ease of maintenance. It was also one of the first British SPGs to adopt the post-war move to turreted self-propelled artillery pieces. In its almost 30-year service life with the British Army, it never fired a shot in anger.
The Abbot is one of the best examples in the world of a military vehicle that has been successful in both military and private sector service. It was loved by its military crews, and continues to be loved by civilian crews.
The FV433 Abbot Self-Propelled Gun (SPG). Based on the FV432 APC, it had a 105mm gun in a fully rotating turret.
The ‘Value Engineered Abbot’ or ‘VEA’, a cheaper, simplified version of the Abbot developed for the Indian Army.
The ‘Falcon’ Self-Propelled Anti-Aircraft Gun (SPAAG), based on the Abbot chassis.
These illustrations were produced by Tank Encyclopedia’s own David Bocquelet.
|Dimensions||19ft 2in x 8ft 8in x 8ft 9in (5.8 x 2.6 x 2.7 meters)|
|Total weight, battle-ready||16 tons (16.2 tonnes)|
|Crew||6 (Commander, Loader/radio operator, Gunner/Layer, Driver/Ammunition Handler, Ammunition Handler, Second in Command/Ammunition Prepper)|
|Propulsion||240 hp Rolls-Royce K60 multi-fuel engine|
|Speed (road)||29 mph (47 kph)|
|Armament||105mm L13A1 Gun
L4 7.62mm Light Machine Gun/GPMG 7.62mm Machine Gun
|Armor||12 – 10mm (0.39 – 0.47in)|
|Total Production||234 (176 FV433s, 88 VEAs)|
Rob Griffin, FV432 Variants, Tankograd Publishing
Profile Publications Ltd. AFV/Weapons #51: Abbot FV433 Self-Propelled Gun, Christopher F. Foss
Wight Military and Heritage Museum
Australian Armour and Artillery Museum (AAAM)