Salisbury Class Aircraft Direction Frigates (Type 61)

Type 61 Cathedral Class

In the final years of the Second World War and the immediately post war years, studies identified the need for a common design of future frigate that would share the same basic hull and machinery design but could be adapted to suit various tasks: anti submarine warfare (ASW), aircraft direction (AD) and anti-aircraft (AA). This common hull would be built in pre-fabricated, all welded sections. In the event of a nuclear war, this would allow for quick assembly as the prefabricated sections could be transported to different shipyards around the country. A further advantage was the basic hull could be laid down and decision on the specific role could be made later in the construction process. Hence this design was both flexible and cost effective.

The drawings for the Type 61 were approved in September 1950 and the first four vessels were ordered on June 28th 1951 and bore the names of Cathedral Cities: Salisbury, Chichester, Llandaff and Lincoln. Salisbury, the lead ship, was laid down on January 1st 1952 and was the first post war frigate built for the Royal Navy. Three further units named Exeter, Coventry and Gloucester were ordered under the 1956-1957 estimates from Fairfied Shipbuilding & Engineering Co, Vickers Armstrong and HM Dockyard Portsmouth, respectively..

Also known as the Salisbury Class, the Type 61 was similar to the Type 41, the same hull and general layout was used, four of each were ordered in June 1951. The Type 61 was laid down first but delays in completion meant the the Type 41 entered service first. In the Type 61 the aft turret was deleted in favour of a 3D 982 Aircraft Direction radar and an extended Operations Room. The aircraft direction variant, known as the Type 61, was designed to counter hostile aircraft by sailing ahead of a fleet or convoy to give early warning of an aircraft attack. They would then direct carrier or shore based aircraft towards the hostile target or engage the target themselves. For this they would be equipped with a range of radar, electronics and communication equipment and appropriate weaponry to provide limited, close range air defence. The principle differences between the Type 61 and the anti-aircraft variant, the Type 41 (Leopard Class), was that instead of a 4.5 inch turret aft, the Type 61 would have an Type 982 air search radar and an enlarged operations room.

Original displacement was designed at 1,738 tons standard and 2,185 full load, but when completed they were 1,950 tons standard and 2,450 full load. Original specification was for 16,000 SHP but in the event no suitable steam plant was available and diesel option was restricted to 12,400 SHP. The first all welded and fully pre-fabricated ships in the RN, designed to be mass produced. When the Type 61 was in development no appropriate steam plant was available and it was feared this type of propulsion could be unsuitable in a crisis or conflict situation. As speed was not as essential as it was with the anti submarine variant, it was decided to use a diesel plant instead. These were designed by the Admiralty and built by Chatham Dockyard and the Type 61 frigates became the first major Royal Navy warships to be powered exclusively by diesels They had a speed of 24 knots and their complement varied in size between 207 and 237

Ships like the Type 61 could operate with a convoy and summon and direct air support from Carriers operating either as escorts or more likely in hunter killer groups.

The 982 aircraft direction radar and later 985 derivitive was only ever fitted to some aircraft carriers beside the Type 61, I know next to nothing about them except the antenna was known as the "Hayrake" and on the carriers they were replaced by the massive 984 radar which looks like a giant searchlight.

The more conventional 960 air warning as used on the Type 41 was also replaced with the 965 as on the Type 41, but the "Double Bedstead" was used, the great AKE(2) which weighed in at 4 tons.

The STAAG was removed and replaced with a twin Mk V Bofors 40mm, and on Lincoln, Salisbury, Chichester & Llandaff this was replaced with the early GWS-20 Seacat system. Squid was fitted to all the class but removed when it became obsolete, neither class ever carried anti-submarine measures in later life.

As with the Type 41 their long range and fuel economy made them ideal for the South America and South Atlantic Patrols. A fifth ship, HMS Exeter, was ordered but then postponned and finaly cancelled.

The four ships of the Salisbury Class served world wide participating in the Beira Patrol, 'Cod Wars' and as guard ships at Hong Kong and Gibraltar. Although Lincoln and Salisbury were fitted with Seacat in the late 1960s, in later years the class became obsolete. Firstly, they were too slow to keep up with the aircraft carriers and other frigates. Whilst the Salisbury Class could only reach 24 knots, the Leander Class could travel at 30 knots as could the aircraft carriers Eagle and Ark Royal. Secondly their principle weaponry of anti-aircraft guns compared unfavourably with newer frigates and destroyers entering service with more sophisticated armaments, notably guided missiles. Consequently after relatively short careers with the Royal Navy, two vessels were sold for scrap, one was sold for service overseas and one was used in a training role before being sunk as a target. only Llandaff surviving to be sold to Bangladesh where she still serves as a training ship.

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