HMS Cossack explained

Six ships of the Royal Navy have borne the name HMS Cossack, after the Cossack people of Eastern Europe, whilst another was begun but was cancelled while building:

• was a 22-gun sixth-rate post-ship, begun under the name Pandour in 1805, but renamed before being launched in 1806. She was broken up in 1816.
• HMS Cossack was to have been a steam gunvessel, laid down at Portsmouth Dockyard in 1846, but cancelled in May 1849.
• was ordered as the Russian ship Witjas, a wood screw corvette building on the Thames at Northfleet, but the British government seized her while she was under construction in 1854; she was sold in 1875.
• was an launched in 1886 and sold in 1905.
• was a destroyer launched in 1907 and sold in 1919.
• was a destroyer launched in 1937 and sunk four days after being torpedoed by the in 1941, when attempts to tow her to safety failed.
• was a destroyer launched in 1944 and broken up in 1961.