Leopard-class frigate

The Type 41 or Leopard class were a class of anti-aircraft defence frigates built for the Royal Navy (4 ships) and Indian Navy (3 ships) in the 1950s.[2][3] The Type 41 and the Type 61 variant introduced diesel-electric propulsion into the Royal Navy for its long range, low fuel use, and fewer necessary crew and skilled artificers, compared with steam turbines, as well as for its less complex (compared to contemporary turbine propulsion) diesel engines.

Leopard class

HMS Jaguar
Class overview
Name:	Leopard class or Type 41
Operators:	Royal Navy  Indian Navy  Bangladesh Navy
Built:	1953–1960
In commission:	1957-1982 (British service) 1958-1992 (Indian service) 1978-2013 (Bangladesh service)
Planned:	5 British & 3 Indian
Completed:	4 British & 3 Indian
Cancelled:	1 British
Retired:	7
General characteristics
Type:	Air-defence frigate
Displacement:	2,300 long tons (2,337 t) standard 2,520 long tons (2,560 t) full load
Length:	340 ft (100 m) o/a
Beam:	40 ft (12 m)
Draught:	16 ft (4.9 m)
Propulsion:	8 × Admiralty Standard Range ASR1 diesels, 14,400 shp (10,738 kW), 2 shafts 220 tons oil fuel[1]
Speed:	24 knots (28 mph; 44 km/h)
Range:	7,500 nmi (13,900 km) at 16 kn (30 km/h)
Complement:	205 or 235
Sensors and processing systems:	Type 960 air search radar, later; 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
Armament:	2 × twin 4.5 in guns Mark 6 1 × twin 40 mm Bofors gun STAAG Mark 2, later; 1 × single 40 mm Bofors gun Mark 9 1 × Squid A/S mortar

Design

These ships were designed to provide anti-aircraft escorts to convoys and light fleet aircraft carriers of the Sydney and Virkant classes and act as light destroyers on detached duties; as a result they were not built for fleet carrier task force speed —28 knots for the Victorious and Audacious classes and made only 24 knots (44 km/h). They were envisioned in late World War II and immediately after as part of the 1944 project for a common hull anti-submarine warfare (A/S), anti-air warfare (A/A), and A/D frigate, and the design of the Type 41 was completed by December 1947.[4]

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[5]), 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.

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 Type 61 or Salisbury-class frigates,[6] 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 A/D ("Aircraft Direction") frigates was, when introduced, largely identical to the reconstructed Dido-class A/D 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 LRAW as compared to the Type 61's four dedicated LRAW systems: types 293, 977M, 960M and 982M.

An intended A/S version, the Type 11 class (see Type system of the Royal Navy), was cancelled due to the low 25-knot top speed being insufficient for accompanying fast carrier task forces, particularly with 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-electric propulsion the Type 41s achieved long range through their low fuel use. 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. 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 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. [7] Adding power-ramming for the twin 4.5" guns, intended to boost the rate of fire from 14rpm to 24rpm, failed. Innovative additions of STAAG ("Stabilised Tachymetric Anti-Aircraft Gun"), CIWS mount, and replacement of the experimental version of the fast rotating 992 target indicators with the slower standard 993 were all abandoned. Only a short range 262 radar MRS1 provided secondary AA fire control for the main armament.

Service

In service the Leopard class were used mainly as patrol frigates, notably on the South American station, where their long range and impressive destroyer-like appearance were particularly advantageous. Operating out of Simonstown in South Africa, [8] they in part replaced the Dido-class cruisers HMS Euralyus and Cleopatra usually deployed on these duties during 1946-1954. It was hoped a pair of Type 41 gunships with four twin-4.5" guns between them would be adequate to deter a single Russian Sverdlov cruiser, which British Naval Intelligence saw as having been in part conceived of to threaten the traditional trade from Buenos Aires to England. Later they were extensively used in the Far East during the 1963–68 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 War duties.[9]

In 1972 it was decided not to refit HMS Puma again, as purchasing the half-sister of the class, the former Black Star ordered by Ghana, and commissioning it as HMS Mermaid, would cost less than a Type 41 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" guns. HMS Lynx was the last of the class operational, in 1977 attending the Spithead fleet review. HMS Jaguar was reactivated from the standby squadron for the 3rd Cod War, but sprang too many leaks on the voyage to Iceland and instead returned to 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:[10] the destroyers and frigates remaining in RN service in 1982 had only one gun turret, the new 4.5" Mk8 often jammed, and the few with the Lynx Mk8 twin-4.5", with 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 useful for long life, the ships being active until they were retired in 2013.

Construction programme

Pennant	Name	(a) Hull builder (b) Main machinery manufacturers	Ordered	Laid down	Launched	Accepted into service	Commissioned	Estimated building cost[11]	Fate
F14	HMS Leopard	(a) HM Dockyard, Portsmouth (b) Vickers Armstrong (Engineers) Ltd, Barrow-in-Furness (b) Peter Brotherhood Limited, Peterborough[12]	21 August 1951[13]	25 March 1953[14]	23 May 1955[14]	December 1958[12]	30 September 1958[14]	£3,545,000[12]	Paid off for last time 12 December 1975.[15] Broken up 1977.[14]
F27	HMS Lynx	(a) John Brown and Co Ltd, Clydebank (b) Crossley Brothers Ltd, Manchester (b) British Polar Engines Ltd, Glasgow[16]	28 June 1951[13]	13 August 1953[14]	12 January 1955[14]	14 March 1957[16]	14 March 1957[14]	£2,720,000[16]	Sold to Bangladesh 12 March 1982, renamed BNS Abu Bakar.[17] Decommissioned 22 January 2013.
F34	HMS Puma	(a) Scotts Shipbuilding and Engineering Co Ltd, Greenock (b) HM Dockyard, Chatham (b) British Polar Engines Ltd, Glasgow[18]	28 June 1951[13]	16 November 1953[14]	30 June 1954[14]	April 1957[18]	27 April 1957[14]	£2,914,000[18]	Paid off for last time June 1972.[15] Broken up 1976.[14]
F37	HMS Jaguar	(a) Wm Denny Bros Ltd, Dumbarton (b) Crossley Bros Ltd, Manchester[19]	28 June 1951[13]	2 November 1953[14]	20 July 1957[14]	December 1959[19]	12 December 1959[14]	£3,772,000[19]	Sold to Bangladesh 6 July 1978 for £2 million,[17] renamed BNS Ali Haider.[14] Decommissioned 22 January 2013.
F34	INS Brahmaputra (ex-HMS Panther)	(a) John Brown and Co Ltd, Clydebank[20]	1954[20]	20 October 1955[20]	13 March 1957[20]		31 March 1958[20]		Ordered HMS Panther, but transferred to India 1953.[14] Decommissioned 30 June 1986 [21] Broken Up 1986.[20]
F37	INS Beas	(a) Vickers Armstrongs (Shipbuilders) Ltd, Newcastle upon Tyne [20]	1954[20]	29 November 1956[20]	9 October 1958[20]		24 May 1960[20]		Decommissioned 22 December 1992[21] Broken up 1992.[20]
F38	INS Betwa	(a) Vickers Armstrongs (Shipbuilders) Ltd, Newcastle upon Tyne[20]	1954[20]	29 May 1957[20]	15 September 1959[20]		8 December 1960[20]		Decommissioned 31 December 1991[21] Broken Up 1988.[20]

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.[14]

Footnotes

1. Gardiner, p. 156
2. Purvis, M.K., 'Post War RN Frigate and Guided Missile Destroyer Design 1944-1969', Transactions, Royal Institution of Naval Architects (RINA), 1974
3. Marriott, Leo, 'Royal Navy Frigates Since 1945', Second Edition, ISBN 0-7110-1915-0, Published by Ian Allan Ltd (Surrey, UK), 1990
4. D.K. Brown & G. Moore. Rebuidling the Royal Navy. Naval Design since 1945. Seaforth. Barnssley (2013) p 74
5. I. Buxton. Shiyard Apprentice. Ships Monthly 4/2019, pp. 36,39
6. Brown & Moore (2012)p 73-4
7. Brown & Moore. Rebilding the RN (2012) p 73-74 & N, Friedman. British Destroyers and Frigates after WW2. Seaforth. Barnsley (2012) p 208-211
8. L. Marriott. Royal Navy Frigates 1945-83. Ian Allen. London (1951), p. 51
9. Marriott.RN frigates. Ian Allen. London (1983) & 1990, p 50-1
10. Marriot.British Frigates 1945-1983(London)1983, p 52
11. "Unit cost, i.e. excluding cost of certain items (e.g. aircraft, First Outfits)."
    Text from Defences Estimates
12. 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
13. 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.
    Moore gives the dates the vessels were ordered as 21 August 1951 for Leopard and 28 June 1951 for the others.
14. Gardiner, Robert Conway's All the World's Fighting Ships 1947–1995, pub Conway Maritime Press, 1995, ISBN 0-85177-605-1 page 516.
    This source says that first orders were placed in August 1951, which contradicts the article by George Moore in Warship, 2004
15. Friedman, Norman British Destroyers and Frigates, the Second World War and After, pub Seaforth, 2006, ISBN 978-1-84832-015-4 page 338.
16. 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
17. Gardiner, Robert Conway's All the World's Fighting Ships 1947–1995, pub Conway Maritime Press, 1995, ISBN 0-85177-605-1 page 23.
18. 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
19. 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
20. Gardiner, Robert Conway's All the World's Fighting Ships 1947–1995, pub Conway Maritime Press, 1995, ISBN 0-85177-605-1 page 174.
21. Hiranandani G.M, Transition to Eminence - The Indian Navy 1976 – 90; pub Lancer New Dehli 2005, ISBN 9788170622666

References

• Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8.
• 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

External links

Media related to Leopard class frigates at Wikimedia Commons