Tank, Medium Gun, FV221 Caernarvon

United Kingdom (1953)
Medium Gun Tank – 11 Built

In 1949, the British Armed Forces were subjected to a ‘financial blizzard’ that swept through the military procurement. As usual, it was driven by the Treasury in an effort to save money. One of the casualties of this storm of cuts was the Army’s newest tank, the FV201, which was already behind schedule, having originally been planned to have been in service two years earlier.

Under fire from the other services over the cost of the program, the Army saw a chance to save some of the development work, and get the new vehicle into service a lot quicker than normal. To achieve this, they needed an intermediary tank to bridge the development gap, this tank was the FV221 Caernarvon.

Born Again Tank

The FV200 series, the British Army’s new universal tank chassis, had been under development since 1944. Nearly all the development work had been done on the hull, and was quite advanced. The turret was less well evolved. Since 1948, there had been a constant desire to improve the anti-tank performance of the FV201. With the cancelation of the FV201 in July of 1949, the Army saw a chance to achieve their aim.

By fitting the L1 120 mm gun in a new turret on the old FV201 hull, they could push the maximum range that the tank could knock out an IS-3 out to 1,000 yards (900 m) when using Armour Piercing Discarding Sabot (APDS). Beyond that range, the L1 120 mm gun could use High Explosive Squash-Head (HESH) warheads. These were judged capable of knocking out the IS-3 and, as they were chemical energy warheads, they could work at any range the new tank could score a hit at. It might seem odd to use the IS-3, a Second World war tank, as a target to measure against. However, this Soviet heavy tank was considered the hardest target in the Soviet arsenal in the post-war period. This was then used as the requirement to beat for most British anti-tank weapons of the time.

The new tank was called the FV214 Conqueror or, officially, the ‘Tank, Heavy No. 1, 120 mm Gun, FV214, Conqueror‘. The chassis was a simplified variant of the FV201 series. The main simplification was in the engine bay, where the power take-off for the additional devices that the FV200 series was to have been fitted with was removed. This simplification meant the tank was slightly shorter. Both of these factors reduced the weight. These savings in weight were reinvested in the tank’s frontal protection, with the glacis being thickened and sloped back slightly more.

There was a problem. Whilst some elements of the hull design were complete and had been tested as part of the development process, troop trials had not been carried out. Troop trials are where the front line soldiers are given some of the pre-production models and asked to test them out in the field. It is a vital step to any tank development and will usually show up a host of problems that need fixing.

In 1949, the chassis was at the stage it could be used for troop trials, after the extensive work having been done on the FV201. However, the turret of the FV214 had not yet been looked at. As it turned out, the design work on the Conqueror’s turret would not start until 1950. Development work on the turret, followed by the troop trials of the complete tank would push the in-service date ever further back until the late 1950s.

During the development of the FV200 series, a couple of the prototypes had been fitted with A.41 Centurion turrets. It was proposed to use the new chassis, fitted with a new roof plate and complete Centurion Mk.III turrets, armed with the standard 20-pounder gun. This new vehicle was to be called the FV221 Caernarvon. The name Caernarvon is the Anglicised name for the town of Caernarfon and its attendant castle in North Wales

Design

The FV221 is a bridging step in the design of British Cold War tanks. On the FV201, there was to be a five man crew, like most Second World War tanks, consisting of a commander, gunner, loader, driver and hull gunner. The last crew member, meant to operate the hull-mounted weapons, usually a machine gun, was deleted from the FV214 design. On the FV221, as it was using the FV201 hull, the hull gunner’s hatch was maintained. However, it lacked the guns and optics such a position would usually entail.

Other than this oddity, the design was entirely standard and followed the now common design of an engine in the back, three crew in the turret and the driver at the front of the hull. The tank itself was largely analogous to the Centurion Mk.III in regards to its performance. Even armed with the same 20-pounder gun that the Centurion had, and was armored the same on the turret.

The hull armor is a lot harder to pin down. On one hand, the FV201 had 76 mm to 89 mm on the front of the hull. However, the requirement was for 130 mm, sloped at least 60 degrees. From documentation, it is not entirely clear what the armor values were, as even official documents give blatantly wrong information, and some contradict each other. This applies even to plans.

Because the tank was conceived in such a haphazard way and outside the normal way tanks were designed, there is limited data on the automotive components. However, from the designated role of that tank, that of providing troop trials for the Conqueror chassis, it can be reasonably speculated that most of the components are the same as the service FV214. According to the website of the Bovington Tank Museum, the FV214 Conqueror had a Rolls Royce Meteor M120 engine giving 860 bhp connected to a Merritt-Brown transmission with 5 forward and two reverse gears. Caution should be taken in translating these characteristics to the Caernarvon, as later events resulted in a re-work to the Conqueror’s engine, so some of these details may have been different for the FV221.

The suspension on the FV221 Caernarvon was of the Horstmann type, coupled in pairs to the Horstmann suspension bogeys. The bogeys were not evenly spaced, with a larger gap being present between the middle two bogeys. The idler wheel was at the front, while the drive sprocket was at the back. The track return was supported by four return rollers hidden behind the upper part of the side skirts.

The Old Foe

The British Army has a long history of being defeated by the Treasury. The FV221 was to fall victim to this department.

Originally, about 160 Caernarvons were planned, but that meant producing 160 chassis that had no fighting potential if a war was to break out. These chassis would be awaiting turrets taken from the normal Conqueror production line, and such a process would take as long as three years. The other option was to purchase a special batch of Centurion turrets, only to throw them away after the troop trials. This was because the tanks used in the troop trials would be converted to Conquerors at a later date. All they needed was their roof plate changed and they could accept a FV214 turret. The purchase of a special batch of Centurion turrets was the preferred option.

Equally, in an effort to begin troop trials, there would be no pre-production version. The first two prototypes would be hand-built and used for component testing only.

Then the Treasury stepped in, aghast at the £70,000 projected unit cost. In comparison, a fully equipped Centurion would cost just £45,000 (£1,404,387.00 today). The Treasury was under pressure from other departments over the Army’s tank project and its costs. A wide-sweeping cull of Army tank development was carried out and numerous tanks, such as the FV4004 Conway and FV217 tank destroyer, were canceled. The reaper also struck at the FV221 project, claiming one of the prototypes and reducing the number of tanks built to about seventy. Even this was not enough and, later, the number was reduced even further to just ten vehicles.

The decision to skip both pre-production tanks did pay off, with the first troop trials starting in 1953. If the usual pre-production step had been carried out, the troop trials would not have started until 1955 at the earliest.

Service

Six FV221s were sent out for the troop trials. One went to British Army of the Rhine, one to Bovington and one to the 4/7th Dragoon Guards. A further two were sent to the Middle East Land Forces (MELF). The last, the prototype, was sent to Bovington. At least two of the tanks were fitted with a strange barrel extension on the end of the 20-pounder gun. It is possible that this was included to simulate the length of the L1 120 mm gun of the Conqueror during the trials process. The tanks, as issued, used FV201 top plates, which retained the hull machine gunner’s position, although no such weapon was fitted. This meant that there was an extra seat, although any crewman sited there would have no actual job to do.

The troop trials very quickly had an effect. It was found that the three episcope arrangement was extremely difficult for the driver to use while driving unbuttoned. This was later changed to a single unit. There was a workshop bulletin posted requiring that the two side episcopes be removed and the holes blocked off with wood. Other changes included work being done on the driver’s hatch locking system and the engine cooling system. The latter was a critical point, as just running the auxiliary generator on the tank could, under the worst-case scenario, cause the cooling system to boil in just 45 minutes.

By 1954, the FV221s owned by MELF had completed over 2,000 miles (3,200 km) running each. The only issues that had been discovered were the aforementioned problems relating to the cooling of the power plant. The troop trials did confirm one series of tests carried out at Bovington, namely that it was impossible to throw a track on this chassis.

In 1955, the Conqueror began to enter service, and the FV221’s were all converted to that type. The only Caernarvon left in existence was the prototype. It soon lost its turret and was used for testing a gas turbine for a period. Then it was used as a dynamo vehicle at Bovington for many years, before finally being converted into the commentary box for the Bovington museum arena. Its final fate in the late 1990s, was to be scrapped when Bovington redeveloped the arena, and this irreplaceable one of a kind tank was handed to the scrap merchants and disappeared from history.

Conclusion

It is estimated that the FV221 managed to cut a year or two off the Conqueror’s service time, and could then claim to have achieved its goal. However, in 1958, shortly after the Conquerors introduction, the entire fleet of the new tank had to be taken off-road due to dust build-up in the engine. This was down to the positioning of the air intake, and should have been caught by the FV221. It may be that this dust problem was exacerbated by a similar, but unrelated problem due to metal build-up caused by unclean standards at the factory, in which case, the carefully constructed FV221 would not have shown the problems up.

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Illustration of the ‘Tank, Medium Gun, FV221 Caernarvon’ produced by Tank Enyclopedia’s own David Bocquelet with additions from Brian S. Gaydos.

Specifications
Dimensions (L-W)	13 feet 1 inch* x 25 feet 4 inches* (3.99* x 7.72 meters*)
Step	3 ft (0.9144 m)*
Trench	11 ft (3.3528 m)
Total weight, battle ready	55 tons*
Crew	4 (Driver, commander, gunner, loader)
Propulsion	Rolls-Royce Meteor M120 810 hp (604 kW)
Suspension	Hortsmann
Speed (road)	22 mph (35 kph)
Armament	20-pounder gun .30 cal Browning.
Armor	Up to 6in (152 mm)**
Total production	11

*Approximate, taken from A.45, which is almost identical.
**Taken from the Centurion Mk.III gun mantle, which is identical.

Sources

WO 185/292: Tanks: TV 200 Series: Policy and Design, 1946-1951, The National Archives, Kew
E2014.747 FV221, Bovington Tank Museum
E2014.627 FV221, Bovington Tank Museum
E2014.1372, Bovington Tank Museum
FV221 Caernarvon – Instructions for User Trials – REME aspect, September 1953, The Tank Museum, Bovington
Maj. Michael Norman, RTR, Conqueror Heavy Gun Tank, AFV/Weapons #38, Profile Publications Ltd.
Carl Schulze, Conqueror Heavy Gun Tank, Britain’s Cold War Heavy Tank, Tankograd Publishing

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