Armed Merchant Cruisers? They were common in WWI and early in WWII, when the supply of warships was tight; you'd take a commercial ship, usually something like an ocean liner, strip out most of the luxury and then mount guns on the deck to act as escorts for convoys.<br/><br/>A typical example of this was the<em>Jervis Bay</em>; she was a 14,000 ton ocean liner of the Aberdeen and Commonwealth Line, that had taken up from trade at the outbreak of WWII, she was outfitted with seven 6in naval guns and two 3in naval guns that had been in storage. On October 28 1940, she was the sole escort for the 37 ships of Convoy HX-84, traveling from Halifax in Nova Scotia to Liverpool; on the 5th of November, the German Pocket Battleship<em>Admiral Scheer</em>loomed over the horizon to set upon HX-84.<br/><br/><em>Jervis Bay</em>stood alone against this tiger of the seas, and for no less than three hours, her elderly guns roared their defiance against the Nazi warship; but in the end, the<em>Jervis Bay</em>was no match, and she was lost to the seas; but she had bought precious time, time for the convoy to scatter, and in the end, only five of the convoy were lost, and one more was damaged. The gallantry and valour of the<em>Jervis Bay</em>was not missed though, and her Captain, Edward Fegen, was posthumously awarded the Victoria Cross for his heroism.