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. These ships were designed to provide anti-aircraft escorts to convoys, as a result they were not built for fleet speeds and made only 24 kn. They shared a common hull and machinery with the Type 61 or Salisbury class aircraft direction vessels. An intended anti-submarine version, the Type 11 class (see Type system of the Royal Navy), was cancelled due to the low top speed being insufficient to combat contemporary adversaries, and was replaced by the turbine powered Type 12. HMS Jaguar and HMS Lynx were sold to the Bangladesh Navy in 1978 and 1982 respectively, and were still in service in 2007.

The Leopard class was also fitted with an early type of hydraulic stabiliser system consisting of two fins that could be extended outside of the main hull to port and starbord, 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 3 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 to allow stowage of loose items over the ship's tannoy system before testing was carried out. Slight reduction in top speed was also noticed when in use.

Construction Programme
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.