View source for Leopard-class frigate

{{Short description|Class of frigate of the Royal Navy}}
{{Use dmy dates|date=August 2021}}
{|{{Infobox ship begin
}}
|+''Leopard'' class
{{Infobox ship image
| Ship image = HMS Jaguar F37.jpg
| Ship caption = HMS ''Jaguar''
}}
{{Infobox ship class overview
|Name= ''Leopard'' class or Type 41
|Builders=
|Operators=*{{navy|United Kingdom}}
*{{navy|India}}
*{{navy|Bangladesh}}
|Class before=
|Class after=
|Subclasses=
|Cost=
|Built range= 1953&ndash;1960
|In service range=
|In commission range=*1957–1982 (British service)
*1958–1992 (Indian service)
*1978–2013 (Bangladesh service)
|Total ships building=
|Total ships planned=5 British & 3 Indian
|Total ships completed=4 British & 3 Indian
|Total ships cancelled=1 British
|Total ships active=
|Total ships laid up=
|Total ships lost=
|Total ships retired=7
|Total ships preserved=
}}
{{Infobox ship characteristics
| Hide header = 
| Header caption = 
| Ship type = Air-defence [[frigate]]
| Ship tonnage = 
| Ship displacement = *{{convert|2300|LT|t|0|lk=in}} standard
*{{convert|2520|LT|t|0}} full load
| Ship length = {{convert|340|ft|m|abbr=on}} [[Length overall|o/a]]
| Ship beam = {{convert|40|ft|m|abbr=on}}
| Ship height = 
| Ship draught = {{convert|16|ft|m|abbr=on}}
| Ship propulsion = *8 × Admiralty Standard Range ASR1 [[diesel engine|diesel]]s, {{convert|14400|shp|0|abbr=on}}, 2 shafts
*220 tons oil fuel<ref>Gardiner, p. 156</ref>
| Ship speed = {{convert|24|kn|mph km/h|lk=in}}
| Ship range = {{convert|7500|nmi|km|abbr=on|lk=in}} at {{convert|16|kn|km/h|abbr=on}}
| Ship complement = 205 or 235
| Ship time to activate = 
| Ship sensors = *Type 960 air search radar, ''later'';
*[[Type 965 radar|Type 965 ''AKE-1'']] air search radar
*Type 293Q target indication radar, ''later'';
*Type 993 target indication radar
*Type 277Q height finding radar
*Type 974 navigation radar
*Type 275 fire control radar on director Mark 6M
*Type 262 fire control radar on director ''CRBF''
*Type 262 fire control radar on ''STAAG'' mount
*Type 1010 [[Cossor]] Mark 10 IFF
*Type 174 search sonar
*Type 164 attack sonar
| Ship EW = 
| Ship armament = *2 × twin [[QF 4.5 inch naval gun|4.5 in guns Mark 6]]
*1 × twin [[Bofors 40 mm Automatic Gun L/60|40 mm Bofors gun]] STAAG Mark 2, later;
*1 × single 40 mm Bofors gun Mark 9
*1 × [[Squid (weapon)|Squid A/S mortar]]
| Ship armour = 
| Ship aircraft = 
| Ship aircraft facilities = 
| Ship notes = 
}}
|}
The '''Type 41''' or '''''Leopard'' class''' were a [[ship class|class]] of [[anti-aircraft]] defence [[frigate]]s built for the [[Royal Navy]] (four ships) and [[Indian Navy]] (three ships) in the 1950s.<ref name=1974RINApaper>Purvis, M.K.,  'Post War RN Frigate and Guided Missile Destroyer Design 1944-1969', Transactions, Royal Institution of Naval Architects (RINA), 1974</ref><ref name=Marriott>Marriott, Leo, 'Royal Navy Frigates Since 1945', Second Edition, {{ISBN|0-7110-1915-0}}, Published by Ian Allan Ltd (Surrey, UK), 1990</ref> The Type 41, together with the [[Salisbury-class frigate|Type 61]] variant, introduced diesel propulsion into the Royal Navy, the perceived benefits being long range, low fuel use, reduced crew (especially skilled artificers), and reduced complexity.

Although successful, improvements in traditional [[steam turbine]] technology erased the fuel economy advantage of the diesel powerplants and led to production being curtailed in favour of the [[Whitby-class frigate|Type 12 frigate]], which was similar in overall design.

== Design ==
These ships were designed to provide anti-aircraft escorts to convoys and amphibious groups and act as light destroyers on detached duties. They were not intended to operate with fleet carrier task forces which had speeds of over 28 knots and were escorted by destroyers and similar vessels, and therefore made only {{convert|24|kn|km/h}}. They were envisioned in late World War II and immediately after as part of a 1945 project for [[anti-submarine warfare|anti-submarine]], [[anti-air warfare|anti-aircraft]], and [[Radar picket#British Aircraft Direction Ships|Aircraft Direction]] frigates which would all share a common hull and propulsion, and the design of the Type 41 was completed by December 1947.<ref name="D.K. Brown 1945. p 74">D.K. Brown & G. Moore. Rebuilding the Royal Navy. Naval Design since 1945. Seaforth. Barnssley (2013) p 74</ref>

Like the 1950 RAN Battle-class variant (actually the Royal Navy variant, for war emergency production) and the unbuilt 1942 two-turret RN G destroyer, which the 1944 common hull escort closely resembles (shipyards building the Type 41, like Dennys Glasgow yard, had been provided with the full 1944 ''Gallant''-class plans<ref>I. Buxton. Shipyard Apprentice. Ships Monthly 4/2019, pp. 36,39</ref>), the Type 41 ''Leopard'' class used the latest twin semi-auto 4.5" Mk6 turrets. This meant that, unlike other post-war frigates, the Type 41 had a full destroyer armament of two twin 4.5" Mk6 gun turrets, giving them a more powerful armament than the Battle- or Weapon-class destroyers.

[[File:HMS Jaguar, 1963 (IWM).jpg|thumb|left|''Jaguar'' underway]]

The first production orders were in the 1951/2 and 1952/3 programmes. In 1953 eleven additional Type 41s, also with "cat" names like ''Cougar'' and ''Cheetah'', were planned, together with ten [[Salisbury-class frigate|Type 61]] (''Salisbury''-class) frigates,<ref>Brown & Moore (2012) p 73-4</ref> with which they shared a common hull and machinery.

Distinct from the Type 61, the Type 41 radar fit also supported surface fighting, whereas the radar fit of the Type 61 "Aircraft Direction" (AD) frigates was, when introduced, largely identical to the reconstructed ''Dido''-class AD cruiser ''Royalist''. To that end, HMS ''Leopard'' carried navigation radar, the new Type 992 for long-range surface target indication, and the Type 960M for Long Range Air Warning; the Type 61 had four dedicated systems: types 293, 977M, 960M and 982M.

An intended A/S version, the Type 11 (see [[Type system of the Royal Navy]]), was cancelled as the low (24-knot) top speed was insufficient for accompanying fast carrier task forces, particularly HMS ''Eagle'', the flagship, commissioned in 1951. However, in practice, frigates and destroyers moving at more than 25 knots create turbulence which blinds their own sonars and can only engage fast-moving subs by using a helicopter with its own sonar. Thus the Type 41s were still fitted with the best late-1950s RN sonars, types 170 and 174 (which remained a good passive sonar into the 1970s), but were equipped with only a minimal A/S mortar battery.

Through their diesel propulsion, the Type 41s achieved long range through their low fuel use. The ships had a total of twelve Admiralty Standard Range Mk.1 (ASR1) diesel engines disposed four-each in three engine rooms. In the fore and aft engine rooms, two engines were connected to the drive shafts by fluid clutches and reduction gearboxes, while the other two were not connected to the shafts, but instead drove 360&nbsp;kW alternators to provide electrical power. In the centre engine room, all four engines were connected to the shafts.<ref>L. Marriott. Royal Navy Frigates 1945-83. Ian Allan. London (1951), p.45-47</ref> ''Jaguar'' was fitted with controllable-pitch propellers.<ref name="L. Marriott 1951 p.51">L. Marriott. Royal Navy Frigates 1945-83. Ian Allan. London (1951), p. 51</ref> Initially the diesel engines proved somewhat unreliable, but these teething troubles were gradually overcome and reliability eventually became very satisfactory.<ref name="D.K. Brown 1945. p 74"/>

The ''Leopard'' class was also fitted with an early type of hydraulic stabiliser system consisting of two fins that could be extended outside the main hull, to port and starboard, from a compartment between the two engine rooms. Gyro controlled with a relatively simple control system, they proved very effective in use. During testing every three months at sea, the ship could be easily driven into a 20°+ roll from the manual control on the bridge. Prior warning had to be given over the ship's tannoy system before testing was carried out, to allow stowage of loose items. A slight reduction in top speed was also noticed when in use.

However, by 1955 success had been achieved, with difficulty and limitations, in developing new steam turbines giving 30-knot speed and the range to take convoys across the Atlantic, embodied in the [[Whitby-class frigate|''Whitby''-class Type 12 frigates]]. As a result, the orders for the new diesel-electric frigates were cancelled, changed to orders for Type 12, or sold to India.

Within a few years of the Type 41's introduction in the late 1950s they were regarded as obsolete for their intended function as anti-aircraft convoy escorts. This was emphasized when the planned replacement of the 4.5" guns with 3"/70 AA guns was abandoned (in January 1955) due to cost and the view that AA guns were obsolete against jets and missiles.<ref>Brown & Moore. Rebuilding the RN (2012) p 73-74 & N, Friedman. British Destroyers and Frigates after WW2. Seaforth. Barnsley (2012) p 208-211</ref> The addition of power-ramming for the twin 4.5" guns, intended to boost the rate of fire from 14rpm to 24rpm, failed. Replacement of the unreliable STAAG [[Bofors 40 mm Automatic Gun L/60|40mm Bofors]] gun mount by [[Seacat (missile)|Seacat]] [[surface to air missile]]s was cancelled on economic grounds, and the guns eventually replaced by a single, manually operated Bofors gun.<ref name="L. Marriott 1951 p.51"/> Replacement of the experimental version of the fast rotating 992 target indicators with the slower standard 993 was also abandoned. Only a short range 262 radar MRS1 provided secondary AA fire control for the main armament.

== Service ==
[[File:Het fregat Jaguar vaart in de haven, Bestanddeelnr 921-6704.jpg|thumb|''Jaguar'' in Amsterdam, 1968]]

In service, the ''Leopard'' class were used mainly as patrol frigates, notably on the South American station, where their long range and  destroyer-like appearance were particularly advantageous.{{Cn|date=July 2022}} Operating out of [[Naval Base Simon's Town|Simonstown naval base]] in South Africa,<ref name="L. Marriott 1951 p.51"/> they in part replaced the ''Dido''-class cruisers [[HMS Euryalus (F15)|HMS ''Euryalus'']] and ''[[HMS Cleopatra (F28)|Cleopatra]]'' usually deployed on these duties during 1946–1954. It was hoped that a pair of Type 41s  with four twin 4.5-inch guns would between them be adequate to deter a single Russian [[Sverdlov-class cruiser|''Sverdlov-class'' cruiser]], which British Naval Intelligence saw as having been in part conceived of to threaten trade routes from [[Buenos Aires]] to  Britain Later they were extensively used in the Far East during the 1963–68 [[Indonesia–Malaysia confrontation|confrontation with Indonesia]] over Borneo and Malaysia, for which all-gun-armed Type 41s were again well suited. In the 1970s they saw service on [[Cod Wars|Cod War]] duties.<ref>Marriott.RN frigates. Ian Allan. London (1983) & 1990, p 50-1</ref>

In 1972 it was decided not to refit HMS ''Puma'' again; purchasing the half-sister of the class, the former ''Black Star'' ordered by Ghana, and commissioning it as HMS ''Mermaid'' would cost less than the refit. HMS ''Leopard'' finished its service in the 1975–1976 Cod War, having given an Icelandic gunboat a 30-second warning that it would open fire with its 4.5-inch guns. HMS ''Lynx'' was the last of the class operational and attend the Spithead fleet review in 1977. HMS ''Jaguar'' was reactivated from the standby squadron for the [[Cod Wars#Third Cod War (1975–1976)|Third Cod War]], but sprang too many leaks on the voyage to Iceland and returned to [[Chatham Dockyard|Chatham]].

HMS ''Jaguar'' and HMS ''Lynx'' were sold to the [[Bangladesh Navy]] in 1978 and March 1982 respectively. Had they been retained a few more years they could have been ideal during the [[Falklands War]] for specialized bombardment and the air defence of ships unloading in [[San Carlos Water]].<ref>Marriot.British Frigates 1945-1983(London)1983, p 52</ref> The destroyers and frigates remaining in RN service in 1982 had only one gun turret, the new 4.5 inch Mk.8 often jammed, and those with the Mk.6 twin 4.5 inch (which required 40–45 men required for each turret) rarely even test fired the guns. As it was, the Bangladesh Navy found the ''Leopard''-class satisfactory and the ships were active until they were retired in 2013.

==Construction programme==
{|class="wikitable" style="font-size:97%;"
|-valign=top
!  | [[Pennant number|Pennant]]
!  | Name
! width="20%"|(a) Hull builder<br />(b) Main machinery manufacturers
!  | Ordered
!  | Laid down
!  | Launched
!  | Accepted into service
!  | Commissioned
!  | Estimated building cost<ref>"Unit cost, i.e. excluding cost of certain items (e.g. aircraft, First Outfits)."<br />Text from ''Defences Estimates''</ref>
! width="20%"|Fate
|-valign=top
|  | F14
|  | [[HMS Leopard (F14)|HMS ''Leopard'']]
|  | (a) HM Dockyard, Portsmouth<br />(b) [[Vickers-Armstrongs|Vickers Armstrong (Engineers) Ltd]], Barrow-in-Furness<br />(b) [[Peter Brotherhood|Peter Brotherhood Limited]], Peterborough<ref name=NE1959>''Navy Estimates, 1959-60'', pages 230-1, ''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 1959''</ref>
|  | 21 August 1951<ref name=Warship2004p134>Moore, George, ''The dawn of the Salisbury, Leopard and Whitby class frigates'' in ''Warship, 2004'', pub Conways, 2004, {{ISBN|0-85177-948-4}} page 134.<br />Moore gives the dates the vessels were ordered as 21 August 1951 for ''Leopard'' and 28 June 1951 for the others.</ref>
|  | 25 March 1953<ref name=Conwaysp516>Gardiner, Robert ''Conway's All the World's Fighting Ships 1947–1995'', pub Conway Maritime Press, 1995, {{ISBN|0-85177-605-1}} page 516.<br />This source says that first orders were placed in August 1951, which contradicts the article by George Moore in ''Warship, 2004''</ref>
|  | 23 May 1955<ref name=Conwaysp516/>
|  | December 1958<ref name=NE1959/>
|  | 30 September 1958<ref name=Conwaysp516/>
|  | £3,545,000<ref name=NE1959/>
|  | Paid off for last time 12 December 1975.<ref name=Friedmanp338>Friedman, Norman ''British Destroyers and Frigates, the Second World War and After'', pub Seaforth, 2006, {{ISBN|978-1-84832-015-4}} page 338.</ref> Broken up 1977.<ref name=Conwaysp516/>
|-valign=top
|  | F27
|  | [[HMS Lynx (F27)|HMS ''Lynx'']]
|  | (a) [[John Brown & Company|John Brown and Co Ltd]], Clydebank<br />(b) [[Crossley Brothers|Crossley Brothers Ltd]], Manchester<br />(b) [[British Polar Engines|British Polar Engines Ltd]], Glasgow<ref name=NE1957>''Navy Estimates, 1957-58'', pages 234-5, ''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 1957''</ref>
|  | 28 June 1951<ref name=Warship2004p134/>
|  | 13 August 1953<ref name=Conwaysp516/>
|  | 12 January 1955<ref name=Conwaysp516/>
|  | 14 March 1957<ref name=NE1957/>
|  | 14 March 1957<ref name=Conwaysp516/>
|  | £2,720,000<ref name=NE1957/>
|  | Sold to [[Bangladesh Navy|Bangladesh]] 12 March 1982, renamed [[BNS Abu Bakr (1982)|BNS Abu Bakr]].<ref name=Conwaysp23>Gardiner, Robert ''Conway's All the World's Fighting Ships 1947–1995'', pub Conway Maritime Press, 1995, {{ISBN|0-85177-605-1}} page 23.</ref> Decommissioned 22 January 2013.
|-valign=top
|  | F34
|  | [[HMS Puma (F34)|HMS ''Puma'']]
|  | (a) [[Scotts Shipbuilding and Engineering Company|Scotts Shipbuilding and Engineering Co Ltd]], Greenock <br />(b) HM Dockyard, Chatham<br />(b) British Polar Engines Ltd, Glasgow<ref name=NE1958>''Navy Estimates, 1958-59'', pages 234-5, ''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 1958''</ref>
|  | 28 June 1951<ref name=Warship2004p134/>
|  | 16 November 1953<ref name=Conwaysp516/>
|  | 30 June 1954<ref name=Conwaysp516/>
|  | April 1957<ref name=NE1958/>
|  | 27 April 1957<ref name=Conwaysp516/>
|  | £2,914,000<ref name=NE1958/>
|  | Paid off for last time June 1972.<ref name=Friedmanp338/> Broken up 1976.<ref name=Conwaysp516/>
|-valign=top
|  | F37
|  | [[HMS Jaguar (F37)|HMS ''Jaguar'']]
|  | (a) [[William Denny and Brothers|Wm Denny Bros Ltd]], Dumbarton<br />(b) Crossley Bros Ltd, Manchester<ref name=NE1960>''Navy Estimates, 1960-61'', pages 226-7, ''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 1960''</ref>
|  | 28 June 1951<ref name=Warship2004p134/>
|  | 2 November 1953<ref name=Conwaysp516/>
|  | 20 July 1957<ref name=Conwaysp516/>
|  | December 1959<ref name=NE1960/>
|  | 12 December 1959<ref name=Conwaysp516/>
|  | £3,772,000<ref name=NE1960/>
|  | Sold to [[Bangladesh Navy|Bangladesh]] 6 July 1978 for £2 million,<ref name=Conwaysp23/> renamed [[BNS Ali Haider (1978)|BNS Ali Haider]].<ref name=Conwaysp516/> Decommissioned 22 January 2013.
|-valign=top
|  |  F34
|  |  [[INS Brahmaputra (1957)|INS ''Brahmaputra'']] (ex-HMS ''Panther'')
|  |  (a) John Brown and Co Ltd, Clydebank<ref name=Conwaysp174>Gardiner, Robert ''Conway's All the World's Fighting Ships 1947–1995'', pub Conway Maritime Press, 1995, {{ISBN|0-85177-605-1}} page 174.</ref>
|  | 1954<ref name=Conwaysp174/>
|  | 20 October 1955<ref name=Conwaysp174/>
|  | 13 March 1957<ref name=Conwaysp174/>
|  | 
|  | 31 March 1958<ref name=Conwaysp174/>
|  | 
|  | Ordered HMS ''Panther'', but transferred to India 1953.<ref name=Conwaysp516/> Decommissioned 30 June 1986<ref name=Hiranandani>Hiranandani G.M, Transition to Eminence - The Indian Navy 1976 – 90; pub Lancer New Delhi 2005, {{ISBN|9788170622666}}</ref> Broken Up 1986.<ref name=Conwaysp174/>
|-valign=top
|  |  F37
|  |  [[INS Beas (1958)|INS ''Beas'']]
|  |  (a) Vickers Armstrongs (Shipbuilders) Ltd, Newcastle upon Tyne<ref name=Conwaysp174/>
|  | 1954<ref name=Conwaysp174/>
|  | 29 November 1956<ref name=Conwaysp174/>
|  | 9 October 1958<ref name=Conwaysp174/>
|  | 
|  | 24 May 1960<ref name=Conwaysp174/>
|  | 
|  | Decommissioned 22 December 1992<ref name=Hiranandani/> Broken up 1992.<ref name=Conwaysp174/>
|-valign=top
|  | F38
|  | [[INS Betwa (1959)|INS ''Betwa'']]
|  | (a) Vickers Armstrongs (Shipbuilders) Ltd, Newcastle upon Tyne<ref name=Conwaysp174/>
|  | 1954<ref name=Conwaysp174/>
|  | 29 May 1957<ref name=Conwaysp174/>
|  | 15 September 1959<ref name=Conwaysp174/>
|  | 
|  | 8 December 1960<ref name=Conwaysp174/>
|  | 
|  | Decommissioned 31 December 1991<ref name=Hiranandani/> Broken Up 1988.<ref name=Conwaysp174/>
|-
|}
A fifth Royal Navy vessel, HMS ''Panther'' was ordered twice.  The first was transferred to India in 1953 before being laid down, a replacement was cancelled in 1957, before being laid down.<ref name=Conwaysp516/>

==Footnotes==
{{Commons category|Leopard class frigates}}

{{reflist}}

==References==
* {{Cite Colledge2006}}
* Gardiner, Robert, ''Conway's All the World's Fighting Ships 1947–1995'' Conway Maritime Press, 1995. {{ISBN|1-55750-132-7}}
* Hiranandani G.M,'Transition to Eminence - The Indian Navy 1976 – 90'; pub Lancer, New Delhi 2005, {{ISBN|9788170622666}}
* Marriott, Leo, 'Royal Navy Frigates Since 1945', Second Edition, {{ISBN|0-7110-1915-0}}, Published by Ian Allan Ltd (Surrey, UK), 1990
* Purvis, M.K., 'Post War RN Frigate and Guided Missile Destroyer Design 1944-1969', Transactions, Royal Institution of Naval Architects (RINA), 1974


{{Leopard class frigate}}
{{Frigates of the Indian Navy}}
{{Ship classes of the Indian Navy}}

[[Category:Frigate classes]]
[[Category:Leopard-class frigates| ]]
[[Category:Ship classes of the Royal Navy]]