Rothesay-class frigate

HMS Plymouth
Class overview
Name	Rothesay class
Operators	Royal Navy  Royal New Zealand Navy  South African Navy
Preceded by	Type 12 Whitby
Succeeded by	Type 12I Leander
Completed	21[1]
Lost	5 (as targets) + 1 (accident)
Retired	16
General characteristics as built
Type	Frigate
Displacement	2,150 long tons (2,185 t) standard 2,560 long tons (2,601 t) full load
Length	370 ft (110 m) o/a
Beam	41 ft (12 m)
Draught	17.3 ft (5.3 m)
Propulsion	Y-100 plant; 2 × Babcock & Wilcox boilers, 2 English Electric steam turbines, 30,000 shp (22,000 kW) on 2 shafts
Speed	30 knots (56 km/h)
Range	400 tons oil fuel; 5,200 nautical miles (9,630 km) at 12 knots (22 km/h)
Complement	152
Sensors and processing systems	Radar Type 293Q target indication Radar Type 275 fire control on director Mark 6M Radar Type 277Q height finder Radar Type 974 navigation Type 1010 Cossor Mark 10 IFF Type 903 radar (MRS-3 system) Sonar Type 174 search Sonar Type 162 target classification Sonar Type 170 attack
Armament	1 × twin 4.5in gun Mark 6 1 × 40 mm Bofors gun Mark 7 2 × Limbo anti-submarine mortar Mark 10 12 × 21-in anti-submarine torpedo tubes (removed or never installed)
General characteristics (as modified)
Displacement	2,380 long tons (2,418 t) 2,800 long tons (2,845 t) full load
Complement	235
Sensors and processing systems	Radar Type 993 target indication Radar Type 903 fire control on director MRS3 Radar Type 978 navigation Type 1010 Cossor Mark 10 IFF Sonar Type 177 search Sonar Type 162 target classification Sonar Type 170 attack
Armament	1 × twin 4.5in gun Mark 6 1 × Sea Cat GWS-20 SAM 2 × 20 mm Oerlikon guns 1 × Limbo anti-submarine mortar Mark 10 2 × 8-barrel 3in Knebworth/Corvus countermeasures launchers
Aircraft carried	1 × Westland Wasp HAS.1 MATCH helicopter
Notes	Other characteristics as per above

The Rothesay class, or Type 12M frigates were a class of frigates serving with the Royal Navy, South African Navy (where they were called President-class frigates) and the Royal New Zealand Navy.^[2][3]

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 class was highly adaptable and further modifications led to the equally successful Leander-class (Type 12I).