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Tribal class frigate

HMS Eskimo
Class overview
Name: Type 81 or Tribal class
Operators:
Preceded by: Blackwood class
Succeeded by: Type 21
Completed: 7
Retired: 4
General characteristics
Type: Frigate
Displacement:
  • 2,300 long tons (2,300 t) standard
  • 2,700 long tons (2,700 t) full load
Length:
  • 360 ft 0 in (109.73 m) oa
  • 350 ft 0 in (106.68 m) pp
Beam: 42 ft 3 in (12.88 m)
Draught:
  • 13 ft 3 in (4.04 m)
  • 17 ft 6 in (5.33 m) (propellers)
Propulsion:
Speed: 27 knots (50 km/h; 31 mph) (COSAG)
Range: 4,500 nautical miles (8,300 km; 5,200 mi) at 12 knots (22 km/h; 14 mph)
Complement: 253
Sensors and
processing systems:
  • Radar type 965 air-search
  • Radar type 993 low-angle search
  • Radar type 978 navigation
  • Radar type 903 gunnery fire-control
  • Radar type 262 GWS-21 fire-control
  • Sonar type 177 search
  • Sonar type 170 attack
  • Sonar type 162 bottom profiling
  • Ashanti and Gurkha;
  • Sonar type 199 variable-depth
Armament:
Aircraft carried: 1 × Westland Wasp helicopter

The Type 81, or Tribal class, were ordered and built as Sloops to carry out similar duties to the immediate post war Improved Black Swan Sloops and Loch class frigates in the Gulf. In the mid 1960s the seven Tribals were reclassified as second class general-purpose frigates for the same reasons as the 21st century reclassification of the USN Littoral Combat ships, to maintain frigate numbers. After the British withdrawal from East of Suez in 1971 the Tribals operated in the Nato North Atlantic sphere with the only update the fitting of Seacat missiles to all by 1977, limited by their single propeller and low speed of 24 knots. In 1979-80 age and crew and fuel shortages, saw them transferred to the stand by squadrons, three being reactivated in 1982 in the Falklands crisis for training and West Indian guardship duties.

The Tribals were designed during the 1950s as a response to the increasing cost of single-role vessels such as the Type 14s. They were first such 'multi role' vessels for the Royal Navy. They were designed specifically with colonial 'gunboat' duties in mind, particularly in the Middle East. They were therefore designed to be self-contained warships with weapon and sensor systems to cover many possible engagements, air conditioning to allow extended tropical deployment and such 'modern' habitability features as all bunk accommodation (as opposed to hammocks). The fitting of gas turbine boost engines was specifically intended to allow the frigates to almostly instantly leave ports and naval bases in the event of nuclear war, rather than have to spend four to six hours to flash up the steam boilers. The G6 gas turbine proved reliable and was generally used to leave port during the frigates career and paved the way for gas turbine propulsion to become universal in the RN within 30 years.

They were the first class of the Royal Navy to be designed from the start to operate a helicopter and the first small escorts to carry a long-range air search radar, the Type 965 with a single 'rake' AKE-1 antenna. They were armed with two 4.5-inch (114 mm) Mark 5 main guns salvaged from scrapped Second World War destroyers. Although these mountings were refurbished with Remote Power Control (RPC) operation, they still required manual loading on an exposed mounting. Originally the intended gun armament was two twin 4-inch (102 mm) Second World War standard mounts, then planning switched to arming them first with the twin 3-inch (76 mm) 70 caliber and then two single automatic 4-inch guns of the sort fitted to the Chilean Almirante Williams class. The automatic guns were rejected on account of weight, space and cost. From the outset they were designed to carry the new GWS-21 Sea Cat anti-aircraft missile system but all except Zulu initially shipped single Mark 7 Bofors guns in lieu. The rest of the class were fitted with Sea Cat in the 1970s using surplus missile systems, leftover from Battle-class destroyers and County-class destroyer refits.


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