|The post-World War II Royal Navy looked towards specialization in its ship construction plans, veering away from the all-purpose fleet destroyer to a new style of
frigate. During World War II, the term frigate was used to identify an escort vessel that was, in terms of size, between a smaller corvette and a larger destroyer.
However, the new frigate envisioned during the 1950s was a much larger vessel than their World War II cousins and comparable to a destroyer in terms of speed and
displacement. The specialization came in terms of the duties the ships would perform: anti-aircraft (A/A), anti-submarine (A/S) and aircraft direction (A/D). To help
further in classifying these ships, all A/S ships would be in the 10s (Types 12, 12M, 14, 15 and 16), A/A in the 40s (Type 41) and A/D in the 60s (Type 61). All
Types had similar hulls, with a high foc’sle deck which sloped down to the gun deck just forward of the bridge. But the armament for each type varied by intended
purpose with the exception of the enclosed twin 4.5-inch turret, which was common to all. Eventually it became clear that specialization was costly, especially in
terms of maintenance and re-equipment, and a decision was made to develop a General Purpose (GP) design that could perform all three functions. The first GP
design was the Type 81 or Tribal class frigate and while there some limitations to this class, the GP concept proved to be a better value.
The Leander class reverted back to the high foc’sle hull of the previous specialized frigates (the Tribals had a more traditional forward hull) and were to be named
after mythological characters, though Cleopatra was an exception as she was a historical figure. The first three ships in the class, Leander, Ajax and Dido, were laid
down as Rothesay class (Type 12M) frigates but now the ships were to incorporate all of the attributes of the specialized predecessors – a Type 965 “bedstead” early
warning radar, twin 4.5-inch gun turret, triple-barreled Limbo A/S mortar, Wasp A/S helicopter, Seacat guided missile weapon system and variable depth sonar.
Largely for this reason, the Leanders were classified as Type 12I for Improved.
The Leander class proved to be a very successful and versatile design. A total of 26 ships were built for the Royal Navy in three batches. The Batch 1 and 2 differed
with the latter receiving an upgraded engine design which improved noise reduction. The Batch 3 ships had two feet added to the beam to improve sea keeping as well
as upgraded engines. The latter batch is referred to as board-beamed Leanders. Two ships were built in the UK and exported to New Zealand and another two were
exported to Chile. Ships based on the Leander class but built under license in foreign yards include the Australian River class, Indian Nigril class and the Dutch Van