The Type 81, or Tribal class, frigates were ordered and built as sloops[3] to carry out similar duties to the immediate post war improved Black Swan-class sloops and Loch-class frigates in the Persian Gulf. In the mid 1960s the seven Tribals were reclassified as second class general-purpose frigates 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,[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 the Falklands War for training and guardship duties in the West Indies.
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 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
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 QF 4.5-in (113 mm) Mark 5 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 open back, mounting. 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's Almirante-class destroyer still required a hull 10 ft (3.0 m) longer[6] and like twin 3/70s, were too expensive. A 3000-ton, light, 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 new GWS-21 Seacat anti-aircraft missile system[9] anti-aircraft missile system but all except Zulu initially carried single Mark 7 40 mm Bofors guns in lieu. The rest of the class were fitted with Seacat in the 1970s[10] using surplus missile systems, left over from Battle-class destroyers and County-class destroyer 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 minelayer HMS Adventure. An additive mix of steam and gas turbine called "COmbined Steam and Gas" COSAG was used. This gave the rapid start-up and acceleration of a gas turbine engine coupled with the cruising efficiency and reliability of the steam 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 1970s Cod Wars in terms of manoeuvering in ramming manoeuvers, 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 some Rothesay-class frigates were given further refits in preference to the Tribals and maintained in higher status reserve in the early 1980s limitations on defence spending.
Shortcomings
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 eight Leanders[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-powered Type 12 (Whitby) class, subsequently modernised in the Type 12M (Rothesay) class and finalised in the excellent Type 12I (Leander)-class. The later Royal Navy Type 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
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 the Persian Gulf and with only a single shaft were unable to manoeuvre with the Icelandic patrol 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 the Falklands War, with 3 mothballed Tribals (Gurkha, Tartar and Zulu) 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 to Indonesia.
(a) JI 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]
(a) JS 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]
(a) Alex Stephen & Sons, Ltd, Linthouse, Glasgow (b) JI Thornycroft & Co Ltd, Southampton (steam and gas turbines) (b) Parsons Marine Turbine Co Ltd, Wallsend-on-Tyne (gearing) [20]
The building costs given above are official figures from the Navy/Defence Estimates. Note that Janes Fighting Ships quotes a slightly lower cost for Ashanti of £5,220,000,[16] as against £5,315,000 quoted in the 1962-63 Navy Estimates.[15]
^"Unit cost, i.e. excluding cost of certain items (e.g. aircraft, First Outfits)." Text from Defences Estimates
^ 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
^ abcdefghijklmnopqrstuvBlackman, Raymond VB Jane's Fighting Ships, 1966-67, pub Sampson Low, Marston & Co Ltd, 1966, page 292.
^ 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
^ 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
^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.
^ 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
Wikimedia Commons has media related to Tribal 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.
tribal, class, frigate, other, uses, tribal, class, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers. For other uses see Tribal class This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Tribal class frigate news newspapers books scholar JSTOR June 2008 Learn how and when to remove this template message The Type 81 or Tribal class frigates were ordered and built as sloops 3 to carry out similar duties to the immediate post war improved Black Swan class sloops and Loch class frigates in the Persian Gulf In the mid 1960s the seven Tribals were reclassified as second class general purpose frigates 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 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 the Falklands War for training and guardship duties in the West Indies HMS EskimoClass overviewNameType 81 or Tribal classOperators Royal Navy Indonesian NavyPreceded byBlackwood classSucceeded byType 21Completed7Retired7General characteristics 2 TypeFrigateDisplacement2 300 long tons 2 300 t standard 2 700 long tons 2 700 t full loadLength360 ft 0 in 109 73 m oa 350 ft 0 in 106 68 m ppBeam42 ft 3 in 12 88 m Draught13 ft 3 in 4 04 m 17 ft 6 in 5 33 m propellers 1 PropulsionSingle shaft COSAG 1 Steam turbine 12 500 shp 9 300 kW 1 Metrovick G 6 gas turbine 7 500 shp 5 600 kW 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 Complement253Sensors and processing systemsRadar 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 depthArmament2 single QF 4 5 inch 113 mm Mark 5 Mod 1 guns 2 single Mark 7 40 mm Bofors guns later 2 four rail GWS 20 Seacat missile systems 2 single 20 mm Oerlikon guns 1 Mark 10 Limbo ASW mortarAircraft carried1 Westland Wasp helicopter Contents 1 History 2 Design 3 Shortcomings 4 Service 5 Ships 6 Footnotes 7 ReferencesHistory EditThe 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 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 EditThey 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 QF 4 5 in 113 mm Mark 5 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 open back mounting 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 s Almirante class destroyer still required a hull 10 ft 3 0 m longer 6 and like twin 3 70s were too expensive A 3000 ton light 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 new GWS 21 Seacat anti aircraft missile system 9 anti aircraft missile system but all except Zulu initially carried single Mark 7 40 mm Bofors guns in lieu The rest of the class were fitted with Seacat in the 1970s 10 using surplus missile systems left over from Battle class destroyers and County class destroyer 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 minelayer HMS Adventure An additive mix of steam and gas turbine called COmbined Steam and Gas COSAG was used This gave the rapid start up and acceleration of a gas turbine engine coupled with the cruising efficiency and reliability of the steam 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 1970s Cod Wars in terms of manoeuvering in ramming manoeuvers 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 some Rothesay class frigates were given further refits in preference to the Tribals and maintained in higher status reserve in the early 1980s limitations on defence spending Shortcomings EditThe 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 eight Leanders 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 powered Type 12 Whitby class subsequently modernised in the Type 12M Rothesay class and finalised in the excellent Type 12I Leander class The later Royal Navy Type 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 EditThe 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 the Persian Gulf and with only a single shaft were unable to manoeuvre with the Icelandic patrol 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 the Falklands War with 3 mothballed Tribals Gurkha Tartar and Zulu 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 to Indonesia Ships EditPennant Name Builder Laid Down Launched Accepted into service Commissioned Estimated building cost 14 FateF117 Ashanti a Yarrow amp Co Ltd Glasgow b Associated Electrica Industries Ltd Manchester 15 15 January 1958 16 9 March 1959 16 November 1961 15 23 November 1961 16 5 315 000 15 Sunk as target 1988F131 Nubian a HM Dockyard Portsmouth b Associated Electrica 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 1987F122 Gurkha a JI Thornycroft amp Co Ltd Southampton b JI Thornycroft amp 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 Indonesian KRI Wilhelmus Zakarias Yohannes 332 F119 Eskimo a JS White amp Co Ltd Cowes Isle of Wight b JS White amp 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 1986F133 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 Indonesian KRI Hasanuddin 333 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 scrapF124 Zulu a Alex Stephen amp Sons Ltd Linthouse Glasgow b JI Thornycroft amp 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 Indonesian KRI Martha Khristina Tiyahahu 331 The building costs given above are official figures from the Navy Defence Estimates Note that Janes Fighting Ships quotes a slightly lower cost for Ashanti of 5 220 000 16 as against 5 315 000 quoted in the 1962 63 Navy Estimates 15 Footnotes Edit Blackman 1971 p 356 Gardiner and Chumbley 1995 p 518 Freidman N 2006 British Destroyers and Frigates The Second World War and After UK Seaforth p 242 Freidman British Destroyers amp Frigates UK 2006 p 247 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 D K Brown 1983 p 18 a b Gardiner Robert ed 1983 All the World s Fighting Ships 1947 1982 Pt One The Western Powers London Conway p 162 P Marland Postwar weapons in the RN in Warship 2015 2015 Conway Lobdon p144 5 148 9 amp 159 Friedman Norman 1991 Naval Institute Guide to Naval Weapons Systems p 410 Preston Antony 1980 Warships of the World London Janes pp 168 9 Brown F K Rebuilding the Royal Navy Warship Design since 1945 p 84 Preston Anthony 1980 Warships of the World London Janes p 169 UK Defence Estimates 63 4 amp 64 5 Unit cost i e excluding cost of certain items e g aircraft First Outfits Text from Defences Estimates a b c d Navy 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 a b c d e f g h i j k l m n o p q r s t u v Blackman Raymond VB Jane s Fighting Ships 1966 67 pub Sampson Low Marston amp Co Ltd 1966 page 292 a b c d e f g h i Navy 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 a b c d e f Defence 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 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 a b c Defence 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 1965References Edit Wikimedia Commons has media related to Tribal class frigates Blackman Raymond V B Jane s Fighting Ships 1971 72 London Sampson Low Marston amp Co 1971 ISBN 0 354 00096 9 Gardiner Robert and Stephen Chumbley Conway s All the World s Fighting Ships 1947 1995 Annapolis Maryland Naval Institute Press 1995 ISBN 1 55750 132 7 Jane s Fighting Ships 1977 78 Jane s Yearbooks ISBN 0 531 03277 9 Retrieved from https en wikipedia org w index php title Tribal class frigate amp oldid 1117842238, wikipedia, wiki, book, books, library,
