Simultaneously, sonar detection capability at long range was also improving significantly, but only short-range weapons were available to surface escort warships.

Known initially under the Rainbow Code name Blue Duck, the Ikara was a "rocket-thrown weapon" with similarities to the French Malafon.

Ikara was powered by a two-stage in-line solid-fuel Murawa rocket engine developed by Bristol Aerojet Ltd in the UK.

[10] A variant fitted to the British Royal Navy's Leander-class frigates differed in several respects from the original Australian version designed to operate in the Pacific.

The Australian practice was to combine the missile and payload at a shore-based ordnance facility and issuing the complete unit to a ship; repair or maintenance was only possible ashore.

[5] The British launcher also differed, covered by a zareba (breakwater) when not in use to prevent icing in northern waters, and extremely accurate in training in bearing.

[citation needed] Ikara was fitted to all of the Royal Australian Navy (RAN) River-class frigates/destroyer escorts and Perth-class guided-missile destroyers.

The British purchased Ikara to fit to the two new CVA-01 aircraft carriers planned (and later cancelled) in the 1960s, and their escorts, the Type 82 destroyers, of which only one, HMS Bristol was built.

With the cancellation of the remaining escorts, the British were left with purchased Ikara missiles in storage, and opted to fit them into eight existing Batch 1 Leander-class frigates in need of modernisation:[13] HM ships Ajax, Arethusa, Aurora, Dido, Euryalus, Galatea, Leander and Naiad.