Overview

The original Type 12 frigates, the Whitby class, were designed as first-rate ocean-going convoy escorts in the light of experience gained during World War II. However, such were the capabilities and potential of the design that it was deemed suitable for use as a fast fleet anti-submarine warfare escort. As such, a repeat and improved Type 12 design was prepared, known as the Type 12M (M for "modified") and called the Rothesay class after the lead ship. A total of twelve vessels were constructed, with the lead ship being laid down in 1956, two years after the last Whitby. The design was successful and popular, serving the Royal Navy and South African Navy well into the 1980s, and serving with distinction in the Falklands War.

The Type 12M retained the hull design of the Type 12. Armament and the propulsion plant remained largely unchanged. The main external differences were an enlarged raked and streamlined funnel and a modified after deckhouse, enlarged to carry the Sea Cat anti-aircraft missile launcher and its associated GWS-20 director and handling rooms as it became available. Internally, electrical generation capacity was increased to handle the increasing demands created by improved ship electronics. Accommodation standards were also improved, with partial bunking and air conditioning. Such was the success of the Rothesay design that it was elaborated into the excellent general purpose Leander-class frigate, the Type 12I.

Increasing submarine performance in the 1960s demanded detection and engagement of targets at a greater distance from the fleet. Detection was improved with new sonar designs such as the Type 177 search and Type 199 Variable depth. To attack targets at a greater range, the Royal Navy adopted the MATCH (Medium-range Anti-submarine Torpedo Carrying Helicopter) system. MATCH was essentially the Westland Wasp HAS.1, a lightweight navalised. All of the Type 12M class were modified and modernised, beginning with Rothesay from 1966 and finishing in 1972.

The after superstructure was removed, along with the foremost Limbo mortar, with the well being plated over to create a small flight deck. A small hangar was constructed in front of this, on top of which the GWS-20 Sea Cat missile and director was shipped. The mainmast was replaced by an enclosed design, carrying the Type 1010 IFF antennas, and the funnel height was increased to carry the hot exhaust gasses over the taller superstructure. The electronics fit was also upgraded from the World War II era sets fitted in the Whitbys. A large, enclosed foremast replaced the short lattice, carrying the distinctive "half cheese" antennas associated with the Type 993 target indicator.

The extensive modifications of the Rothesays brought their armament and anti submarine capabilities into line with the that of the original Leander-class vessels. In 1978, Rothesay went into refit for two years at a cost of 33.4 million pounds Yarmouth and Plymouth completed similar refits in 1981, which included fitting 994 short range warning radar and target indicator essentially in the old antenna, giving faster screen data in the Rothesays' operations room.

Aviation facilities:
Flight deck and enclosed hangar for embarking one helicopter

Aircraft carried
1× Wasp HAS.1,

HMS Yarmouth

Builder

John Brown & Co. Ltd., Clydebank

Laid down

29. November 1957

Launched

23.March 1959

Commissioned

26. March 1960

30. April 1986

Deckcode YM

829 NAS
Apr. 1968 - Dec. 1978

829 NAS 032 Flight
Dec. 1980 - May 1986

HMS Rothesay

Builder

Yarrow & Co Ltd, Glasgow.

Laid down

Launched

Commissioned

Deckcode RO

829 NAS 035 Flight
May 1968 - Sep. 1977

829 NAS 024 Flight
Mar. 1980 - Mar. 1988

HMS Londonderry

Builder

JS White & Co. Ltd., Cowes, Isle of Wight

Laid down

15. November 1956

Launched

20. May 1958

Commissioned

18. October 1961

29. March 1984

Deckcode LD

829 NAS
Nov- 1969 - Oct. 1975

HMS Rhyl

Builder

HM Dockyard, Portsmouth,

Laid down

Launched

Commissioned

Deckcode RL

829 NAS 034 Flight
Jan. 1972 - Apr. 1974

829 NAS 021 Flight
Aug. 1976 - Dec. 1976

829 NAS 045 Flight
Jun. 1977 - Oct 1978

829 NAS
Jan. 1979 - Aug. 1979

829 NAS 029 Flight
Aug. 1979 - May 1982

829 NAS 026 Flight
May 1982 - Aug 1982

829 NAS 029 Flight
Aug. 1982 - Jul. 1983

HMS Plymouth

Builder

HM Dockyard, Devonport

Laid down

1. July 1958

Launched

20. July 1959

Commissioned

11. May 1961

26. April 1988

Deckcode PL

829 NAS
Dec. 1968 - Jul. 1971

829 NAS 032 Flight
Oct. 1971 - Apr. 1974

829 NAS
Nov. 1974 - Sep. 1978

829 NAS 027 Flight
Oct. 1980 - May 1988

HMS Berwick

Builder

Laid down

Launched

Commissioned

Deckcode BK

829 NAS
Jan. 1971 - Sep. 1973

829 NAS 032 Flight
Apr. 1974 - Dec. 1980

829 NAS 040 Flight
Jun. 1982 - Oct. 1985

HMS Falmouth

Builder

Swan Hunter & Wigham Richardson Ltd., Wallsend-on-Tyne

Laid down

23. November 1957

Launched

15. December 1959

Commissioned

25. July 1961

July 1984

Deckcode FM

829 NAS 010 Flight
Nov. 1970 - Feb. 1977

829 NAS 023 Flight
Mar. 1977 - Apr. 1980

829 NAS 042 Flight
Apr. 1982 - Nov. 1984

HMS Lowestoft

Builder

Alex Stephens & Sons Ltd., Linthouse, Glasgow

Laid down

9. June 1958

Launched

23. June 1960

Commissioned

26. September 1961

1985

Deckcode LT

829 NAS
Feb. 1970 - Jun. 1973

829 NAS
Oct. 1973 - Sep. 1976

829 NAS 036 Flight
Jul. 182 - Mar. 1985

HMS Brighton

Builder

Yarrow & Co. Ltd., Glasgow

Laid down

23 July 1957

Launched

30 October 1959

Commissioned

28 September 1961

1981

Deckcode BR

829 NAS
Dec. 1971 - Oct. 1974

829 NAS 034 Flight
Apr. 1975 - Apr. 1981

History 

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