Unsinkable Sam (also known as Oskar or Oscar) was the nickname of an alleged German ship's cat who reportedly saw service in both the Kriegsmarine and Royal Navy during the Second World War, serving on board three vessels and surviving the sinking of all three.
The black and white patched cat had been owned by an unknown crewman of the German battleship Bismarck. He was on board the ship on 18 May 1941 when it set sail on Operation Rheinübung, Bismarck's first and only mission. Bismarck was sunk after a fierce sea-battle on 27 May, from which only 118 from its crew of over 2,200 survived. Hours later, Oscar was found floating on a board and picked from the water, the only survivor (alongside 114 others) to be rescued by the homeward-bound British destroyer HMS Cossack. Unaware of what his name had been on Bismarck, the crew of Cossack named their new mascot "Oscar".
The cat served on board Cossack for the next few months as the ship carried out convoy escort duties in the Mediterranean and north Atlantic. On 24 October 1941, Cossack was escorting a convoy from Gibraltar to Great Britain when it was severely damaged by a torpedo fired by the German submarine U-563. Crew were transferred to the destroyer HMS Legion, and an attempt was made to tow the badly listing Cossack back to Gibraltar, but worsening weather conditions meant the task became impossible and had to be abandoned. On 27 October, a day after the tow was slipped, Cossack sank to the west of Gibraltar. The initial explosion had blown off one third of the forward section of the ship, killing 159 of the crew, but Oscar survived this too and was brought to the shore establishment in Gibraltar.
Now nicknamed "Unsinkable Sam", he was soon transferred to the aircraft carrier HMS Ark Royal, which coincidentally had been instrumental in the destruction of Bismarck. However, Sam was to find no more luck there, and when returning from Malta on 14 November 1941, this ship too was torpedoed, this time by U-81. Attempts were also made to tow Ark Royal to Gibraltar, but the unstoppable inflow of water made the task futile. The carrier rolled over and sank 30 miles from Gibraltar. The slow rate at which the ship sank meant that all but one of the crew could be saved. The survivors, including Sam, who had been found clinging to a floating plank by a motor launch, and described as "angry but quite unharmed" were transferred to HMS Lightning and the same HMS Legion which had rescued the crew of Cossack. Legion would itself be sunk in 1942, and Lightning in 1943.
The loss of Ark Royal proved the end of Sam's shipborne career and he was transferred first to the offices of the Governor in Gibraltar, and then sent back to the United Kingdom, where he saw out the remainder of the war living in a seaman's home in Belfast called the "Home for Sailors".
Sam died in 1955.
A pastel portrait of Sam (titled "Oscar, the Bismarck's Cat") by the artist Georgina Shaw-Baker is in the possession of the National Maritime Museum, Greenwich.
Some authorities question whether Oskar/Sam's biography might be a "sea story", because for example, there are pictures of two different cats identified as Oskar/Sam. The sinking of the Bismarck, and rescue of a limited number of survivors, took place in desperate conditions; British ships were ordered not to stop as there was believed to be a U-boat in the area and many survivors were left to drown. There is no mention of this incident in Ludovic Kennedy's detailed account of the sinking.