Leander-class Frigate

### Operators

United Kingdom, Pakistan, Ecuador, Indonesia (main class), Chile, Australia, Netherlands, India, New Zealand (subclasses)

### Commissioned

1963-1993 (main class, Briitish ships), 1963-present (subclasses included)

### Derivatives

Condell-class, River-class, Nilgiri-class, Van Spejik-class

The ***Leander*-class**, or **Type 12I (Improved) frigates**, comprising twenty-six vessels, was among the most numerous and long-lived classes of frigate in the Royal Navy's modern history. The class was built in three batches between 1959 and 1973. It had an unusually high public profile, due to the popular BBC television drama series *Warship*. The *Leander* silhouette became synonymous with the Royal Navy through the 1960s until the 1980s.

The *Leander* design or derivatives of it were built for other navies:

* Royal New Zealand Navy as the *Leander* class
* Chilean Navy: *Condell* class
* Royal Australian Navy: River class
* Indian Navy: *Nilgiri* class
* Royal Netherlands Navy: *Van Speijk* class

### Design

The policy adopted by the Royal Navy during the 1950s of acquiring separate types of frigates designed for specialised roles (i.e. anti-submarine, anti-aircraft and aircraft direction) had proved unsatisfactory. Although the designs themselves had proved successful, the lack of standardisation between the different classes led to increased costs during construction and also in maintenance once the ships became operational. Furthermore, it was not always possible to have the ships with the required capabilities available for a specific task. The first move towards creating a truly general-purpose frigate came with the Type 81 Tribal class which was initially ordered in 1956. The 24-knot speed of the Tribals was considered the maximum possible for tracking submarines with the new medium-range sonars, entering service. The type 81 gas turbine saw the frigates underway quickly, without taking hours flashing up steam turbines, and the provision of a helicopter for long-range attack were considered essential in the nuclear age. These ships were mainly intended to operate in the tropics but lacked the speed and armament required for the priority fleet carrier escort role East of Suez, where fast radar picket capability was important, as much as anti-submarine capability. So the new frigates would combine the roles of the T12 and T61. The fully air-conditioned Royal New Zealand Navy *Rothesay* class variant, HMNZS *Otago*, which gave all the crew a bunk and cafeteria messing and a RNZN commissioned design study for a more fully capable Type 12 frigate, which also assessed whether the Type 12 could carry 2 of the larger Wessex AS helicopters, was used as the basis of the RN Leander Improved Type 12 design.

On 7 March 1960, the Civil Lord of the Admiralty C. Ian Orr-Ewing stated that the "Type 12 *Whitby*-class anti-submarine frigates are proving particularly successful ... and we have decided to exploit their good qualities in an improved and more versatile ship. This improved Type 12 will be known as the *Leander* class. The hull and steam turbine machinery will be substantially the same as for the *Whitby*s. The main new features planned are a long-range air warning radar, the Seacat anti-aircraft guided missile, improved anti-submarine detection equipment and a light-weight helicopter armed with homing torpedoes. We shall also introduce air conditioning and better living conditions." The 1963 edition of *Jane's Fighting Ships* described it as a "mainly anti-submarine but flexible and all-purpose type".

> The *Leander* class have the same hull and substantially the same steam turbine machinery as the *Whitby* class, but are a revised and advanced design and will fulfil a composite anti-submarine, anti-aircraft and air direction role. The 40mm guns will eventually be replaced by *Seacat* ship-to-air launchers. The ships are equipped with VDS (Variable Depth Sonar), formerly known as dipping asdic.
> —
>
>

The difference between the *Leander*s (Type 12I) and the *Whitby*s (Type 12) was most obviously that the stepped quarterdeck of the Type 12 had been done away with, resulting in a flush deck, with the exception of the raised forecastle. The superstructure had been combined into a single block amidships and a new bridge design gave improved visibility. A hangar and flight deck were provided aft for the Westland Wasp light anti-submarine helicopter, which was still at the prototype stage when the first ships were ordered. The ship was air conditioned throughout and there were no portholes in order to improve nuclear, biological and chemical defence. The ships were all given names which had previously been given to Royal Navy cruisers, mostly of characters from classical mythology, the exceptions being *Cleopatra* and *Sirius*.

The Y160 boiler variant used on the Batch 3 *Leander*s (such as *Jupiter*) also incorporated steam atomisation equipment on the fuel supply so the diesel fuel entering the boilers *via* the three main burners was atomised into a fine spray for better flame efficiency. Some ships with Y100 Boilers were also converted to steam atomisation, HMS *Cleopatra* being one of them. The superheat temperature of the Y160 was controlled manually by the boiler room petty officer of the watch between 750–850 °F (399–454 °C) and the steam supplied to the main turbines was at a pressure of 550 psi (3,800 kPa). The *Leander*-class frigates did have Babcock & Wilcox boilers but of a more conventional two-drum design, one water drum and one steam drum, much like a Yarrow boiler without the second water drum. The water drum was offset to one side and below the furnace and steam drum. The two boilers fitted were 'handed' with the water drum inboard on both. Many *Leander*s had six-burner furnaces (known as Five and a Half Boilers) and the output was varied by altering the number of burners in use.

### Armament

* 2 × 4.5-inch guns (1 × twin mounting Mk6)
* 1 × Seacat surface-to-air missile launcher
* 2 × 20mm guns (single mountings)
* 2 × 40mm Mk VII Bofors (single mountings) initially in first 7 instead of Seacat & 20mm guns
* 1 × ASW Limbo mortar
* *Batch 1 - Ikara*:
* 1 × Ikara Anti-submarine missile Launcher
* 2 × Seacat surface-to-air missile launchers
* 2 × 40mm guns - single mountings
* 2 × triple 324 mm (12.75) STWS-1 tubes for Mk 46 and Stingray ASW torpedoes
* 1 × Limbo ASW Mortar
* *Batch 2 - Exocet/Seacat*:
* 4 × MM.38 Exocet anti-ship missile launchers
* 3 × Seacat surface-to-air missile launchers
* 2 × 40mm guns - single mountings
* 2 × triple 324 mm (12.75 inch) STWS-1 tubes for Mk 46 and Stingray ASW torpedoes
* *Batch 3 - Exocet/Seawolf*:
* 4 × MM.38 Exocet anti-ship missile launchers
* 1 × sextuple GWS.25 launcher with 30 Sea Wolf SAMs
* 2 × 20mm AA guns
* 2 × triple 324 mm (12.75) STWS-1 tubes for Mk 46 and Stingray ASW torpedoes

### Ships in Class

does NOT include subclasses

* HMS Leander (F109)
* HMS Dido (F104)
* HMS Penelope (F137)
* HMS Ajax (F114)
* HMS Aurora (F10)
* HMS Galatea (F18)
* HMS Euryalus (F15)
* HMS Naiad (F39)
* HMS Arethusa (F38)
* HMS Cleopatra (F28)
* HMS Pheobe (F42)
* HMS Minerva (F45)
* HMS Sirius (F40)
* HMS Juno (F52)
* HMS Argonaut (F56)
* HMS Danae (F47)
* HMS Charybdis (F75)
* HMS Hermione (F58)
* HMS Jupiter (F60)
* HMS Bacchante (F69)
* HMS Andromeda (F57)
* HMS Scylla (F71)
* HMS Achilles (F12)
* HMS Diomede (F16)
* HMS Apollo (F70)
* HMS Ariadne (F72)

### RNZN

* HMNZS Waikato
* HMNZS Canterbury (F421)