Wikipedia

Tribal-class frigate

For other uses, seeTribal-class.

TheType 81,orTribal class,frigates were ordered and built assloops[3]to carry out similar duties to the immediate post war improvedBlack Swan-class sloopsandLoch-class frigatesin thePersian Gulf.In the mid 1960s the seven Tribals were reclassified as second class general-purposefrigatesto maintain frigate numbers. After the British withdrawal from East of Suez in 1971 the Tribals operated in theNATONorth Atlantic sphere with the only update the fitting ofSeacat missilesto all by 1977,[4]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 were reactivated in 1982 during theFalklands Warfor training and guardship duties in theWest Indies.

Class overview
NameType 81 or Tribal class
Operators
Preceded byBlackwoodclass
Succeeded byType 21
Built1958–1964
In commission1961–2000
Completed7
Retired7
General characteristics[1]
TypeFrigate
Displacement
  • 2,300long 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
Beam42 ft 3 in (12.88 m)
Draught
  • 13 ft 3 in (4.04 m)
  • 17 ft 6 in (5.33 m) (propellers)[2]
Propulsion
Speed27 knots (50 km/h; 31 mph) (COSAG)
Range4,500 nautical miles (8,300 km; 5,200 mi) at 12 knots (22 km/h; 14 mph)
Complement253
Sensors and
processing systems
  • Radartype 965 air-search
  • Radar type 993 low-angle search
  • Radar type 978 navigation
  • Radartype 903gunnery fire-control
  • Radar type 262 GWS-21 fire-control
  • Sonartype 177 search
  • Sonar type 170 attack
  • Sonar type 162 bottom profiling
  • AshantiandGurkha;
  • Sonar type 199 variable-depth
Armament
Aircraft carried1 ×Westland Wasphelicopter

History

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The Tribals were designed during the 1950s as a response to the increasing cost of single-role vessels such as theType 14s.They were first such 'multi role' vessels for theRoyal Navy.They were designed specifically with colonial 'gunboat' duties in mind, particularly in theMiddle 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 almost 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.

Design

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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 searchradar,theType 965with a single 'rake' AKE-1antenna.They were armed with twoQF 4.5-in (113 mm) Mark 5 gunssalvaged from scrappedSecond World Wardestroyers. Although these mountings were refurbished with Remote Power Control (RPC) operation, they still required manual loading on an exposed open back.

Originally the intended gun armament was two twin 4-inch (102 mm) Second World War standard mounts, then twin 3-inch (76 mm) 70 caliber mounts which 256 ton weight for 2 turrets was too heavy.[5]A lighter automatic gun fit of two N(R) single automatic 4-inch guns, as fitted in Chile'sAlmirante-class destroyer still required a hull 10 ft (3.0 m) longer[6]and like twin 3/70s, were too expensive.

A 3000-ton displacement exceeded the limit the UK Treasury would allow for a sloop or frigate design in the 1960s[7]so both automatic guns were rejected on account of weight, space and cost.[7]Even though they provided a realistic solution to the RN AA/ DP gun requirement, due to cost, and the problem of cost of developing stocks and logistic support, for new types of ammunition and doubt of the usefulness of medium gun AA against post 1962 jet air and missile targets.[8]

From the outset they were designed to carry the newGWS-21 Seacatanti-aircraft missile system[9]anti-aircraft missile system but all exceptZuluinitially carried single Mark 740 mm Bofors gunsin lieu. The rest of the class were fitted with Seacat in the 1970s[10]using surplus missile systems, left over fromBattle-classdestroyers andCounty-classdestroyer refits.

The Tribals were the first modern RN ships designed to use a combination of power sources, a feature which had been trialled with limited success in the 1930s in the minelayerHMSAdventure.An additive mix of steam and gas turbine called "COmbined Steam and Gas"COSAGwas used. This gave the rapid start-up and acceleration of agas turbineengine coupled with the cruising efficiency and reliability of thesteam turbine.They would cruise on the steam plant and use both systems driving the same shaft for a high-speed "boost". They suffered however from being single-shaft vessels which severely limited manoeuvrability, acceleration and deceleration. The single screw proved significantly limiting when they were used in the 1970sCod Warsin terms of manoeuvering in ramming manoeuvres, for and against, Icelandic coast guard cutters. The cramped awkward nature of the helicopter pad and handling provision was also exposed in the 1976 Cod War and was a major reason that someRothesay-classfrigates were given further refits in preference to the Tribals and maintained in higher status reserve in the early 1980s limitations on defence spending.

Shortcomings

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The costs for the Tribal Class ships escalated above the costs first envisaged and the original order of ships, (over twenty), was cancelled after the first seven ships had been completed. Only four would have been built if it had been possible to cancel the contractual commitments the Royal Navy had entered into for the supply of complex engines and machinery[11]for eight frigates. The ships were rather small, at 360 ft (110 m), which reduced the options for later modernisation and were always going to be limited by their single-shaft propulsion. The class were still good warships in spite of being fitted with outdated guns, (they were described by some as 'guided flagpoles')[12]if sometimes capable of 18 rounds per minute for the first two minutes, and proved the usefulness of the general purpose frigate concept and gas turbine propulsion, but the average unit costs of the Type 81s completed in 1963-64 was £500,000 more than the first eightLeanders[13]and the final cost of over £5 million of the first Tribal,Ashanti,completed in 1961 was considered too high and hence limited the number actually built; the original intent was to build 23 Type 81s. This meant that further 1960s RN frigate development would be based on the more conservative steam-poweredType 12 (Whitby) class,subsequently modernised in theType 12M (Rothesay) classand finalised in the excellentType 12I (Leander)-class.The later Royal NavyType 21 (Amazon) class"General Purpose Frigates" were originally envisaged for a similar gunboat role to the Tribal-class ships and to operate East of Suez.

Service

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The class served throughout the 1960s and into the 1970s fulfilling their designed general purpose "colonial gunboat" role. When change in British foreign policy made this role redundant they found themselves being pressed into service in home waters in the Cod Wars of the 1970s. They were not particularly suited to these duties however, as they had a hull form optimised for the calm, shallow water of thePersian Gulfand with only a single shaft were unable to manoeuvre with theIcelandicpatrol vessels at close quarters.

All were decommissioned from the Royal Navy during the mid-to-late 1970s with the manpower crisis also attributing to the rapid removal of the class from service. They were however given a brief reprieve by theFalklands War,with 3 mothballed Tribals (Gurkha,TartarandZulu) being reactivated to cover ships deployed to the South Atlantic or undergoing long-term repairs after the conflict. The remaining units were cannibalised for spare parts to enable the 3 ships to be refitted. These ships were sold in 1984 toIndonesia.

Ships

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Pennant Name Builder Laid Down Launched Accepted into service Commissioned Estimated building cost[14] Fate
F117 Ashanti (a)Yarrow & Co Ltd,Glasgow
(b)Associated Electrical IndustriesLtd, Manchester[15] 		15 January 1958[16] 9 March 1959[16] November 1961[15] 23 November 1961[16] £5,315,000[15] Sunk as target 1988
F131 Nubian (a)HM Dockyard,Portsmouth
(b) Associated Electrical Industries Ltd, Manchester[17] 		7 September 1959[16] 6 September 1960[16] November 1962[17] 9 October 1962[16] £4,360,000[17] Sunk as target 1987
F122 Gurkha (a)J I Thornycroft & Co Ltd,Southampton
(b) JI Thornycroft & Co Ltd, Southampton (steam and gas turbines)
(b) Parsons Marine Turbine Co Ltd, Wallsend-on-Tyne (gearing)[17] 		3 November 1958[16] 11 July 1960[16] February 1963[17] 13 February 1963[16] £4,865,000[17] IndonesianKRIWilhelmus Zakarias Yohannes(332),stricken 2000
F119 Eskimo (a)J S White & Co Ltd,Cowes, Isle of Wight
(b) JS White & Co Ltd, Cowes, Isle of Wight (steam and gas turbines)
(b) Fairfield Shipbuilding and Engineering Co Ltd, Govan, Glasgow (gearing)[17] 		22 October 1958[16] 20 March 1960[16] February 1963[17] 21 February 1963[16] £4,560,000[17] Sunk as target 1986
F133 Tartar (a)HM Dockyard,Devonport
(b) Vickers-Armstrongs (Engineers) Ltd, Barrow-in-Furness (steam turbines and gearing)
(b) Yarrow and Co Ltd, Glasgow (gas turbine)[18] 		22 October 1959[16] 19 September 1960[16] April 1963[18] 26 February 1962[16] £4,300,000[18][19] IndonesianKRIHasanuddin(333),stricken 2000
F125 Mohawk (a)Vickers-Armstrongs (Shipbuilders) Ltd,Barrow-in-Furness
(b) Associated Electrical Industries Ltd, Manchester (gas turbine)
(b) Vickers-Armstrongs (Engineers) Ltd, Barrow-in-Furness (steam turbines and gearing)[18] 		23 December 1960[16] 5 April 1962[16] December 1963[18] 29 November 1963[16] £4,750,000[18] Sold for scrap
F124 Zulu (a)Alex Stephen & Sons Ltd,Linthouse, Glasgow
(b) J I Thornycroft & Co Ltd, Southampton (steam and gas turbines)
(b) Parsons Marine Turbine Co Ltd, Wallsend-on-Tyne (gearing)[20] 		13 December 1960[16] 3 July 1962[16] April 1964[20] 17 April 1964[16] £5,100,000[20] IndonesianKRIMartha Khristina Tiyahahu(331),stricken 2000

The building costs given above are official figures from the Navy/Defence Estimates. Note thatJanes Fighting Shipsquotes a slightly lower cost forAshantiof £5,220,000,[16]as against £5,315,000 quoted in the1962-63 Navy Estimates.[15]

Footnotes

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  1. ^Gardiner and Chumbley 1995, p. 518.
  2. ^Blackman 1971, p. 356.
  3. ^Freidman, N. (2006),British Destroyers and Frigates. The Second World War and After,UK: Seaforth, p. 242
  4. ^Freidman. British Destroyers & Frigates. UK (2006), p. 247
  5. ^D. K. Brown.A Century of Naval Construction. The History of Royal Corps of Naval constructors 1883-1983.Conway Maritime. (1983) London, pp. 17-18
  6. ^D.K. Brown (1983) p 18
  7. ^abGardiner, Robert, ed. (1983).All the World's Fighting Ships 1947-1982. Pt One. The Western Powers.London: Conway. p. 162.
  8. ^P.Marland. Postwar weapons in the RN in Warship 2015.(2015) Conway.Lobdon, p144-5,148-9 & 159
  9. ^Friedman, Norman (1991).Naval Institute Guide to Naval Weapons Systems.p. 410.
  10. ^Preston, Antony (1980).Warships of the World.London: Janes. pp.168–9.
  11. ^Brown, F.K.Rebuilding the Royal Navy: Warship Design since 1945.p. 84.
  12. ^Preston, Antony (1980).Warships of the World.London: Janes. p.169.
  13. ^UK Defence Estimates 63-4 & 64-5
  14. ^"Unit cost, i.e. excluding cost of certain items (e.g. aircraft, First Outfits)."
    Text fromDefences Estimates
  15. ^abcdNavy Estimates, 1962-63,pages 218-9,List and particulars of new ships which have been accepted or are expected to be accepted into HM service during the Financial Year ended 31 March 1962
  16. ^abcdefghijklmnopqrstuvBlackman, Raymond VBJane's Fighting Ships, 1966-67,pub Sampson Low, Marston & Co Ltd, 1966, page 292.
  17. ^abcdefghiNavy Estimates, 1963-64,page 71,List and particulars of new ships which have been accepted or are expected to be accepted into HM service during the Financial Year ended 31 March 1963
  18. ^abcdefDefence Estimates, 1964-65,page 73,Table 3 (Programme): List and particulars of new ships which have been accepted or are expected to be accepted into HM service during the Financial Year ended 31 March 1964
  19. ^Note that the 1963-64 naval estimates gave an estimated acceptance date of March 1963, and an estimated building cost of £4,205,000. Presumably the explanation is that the 1964-65 estimates are correct, and the 1963-64 proved optimistic.
  20. ^abcDefence Estimates, 1965-66,page 75,Table 3 (Programme): List and particulars of new ships which have been accepted or are expected to be accepted into HM service during the Financial Year ended 31 March 1965

References

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Wikimedia Commons has media related toTribal class frigates.
  • Blackman, Raymond V.B.Jane's Fighting Ships 1971–72.London: Sampson Low, Marston & Co, 1971.ISBN0 354 00096 9.
  • Gardiner, Robert and Stephen Chumbley.Conway's All the World's Fighting Ships 1947–1995.Annapolis, Maryland: Naval Institute Press, 1995.ISBN1-55750-132-7.
  • Jane's Fighting Ships 1977-78,Jane's Yearbooks,ISBN0-531-03277-9
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