Italian auxiliary ship Olterra

Italian auxiliary ship Olterra
Part of the Battle of the Mediterranean of World War II

Olterra at anchor shortly before being broken up at Vado Ligure, 1961
Date8 December 1942 – 4 August 1943
Location
Result 42,000 GRT of Allied shipping sunk
Belligerents
 United Kingdom  Italy
Commanders and leaders
Lionel Crabb Licio Visintini 
Ernesto Notari
Strength
Harbour defences 1 mother ship
9 human torpedoes
Casualties and losses
6 merchant ships sunk
2 sailors killed
3 divers killed
3 prisoners
2 manned torpedoes lost

The auxiliary ship Olterra was a 5,000 GRT Italian tanker scuttled by her crew at Algeciras in the Bay of Gibraltar on 10 June 1940, after the entry of Italy into the Second World War. She was recovered in 1942 by a special unit of the Decima Flottiglia MAS to be used as a clandestine base for manned torpedoes to attack Allied shipping at Gibraltar.