Italian Auxiliary Ship Olterra - Refitting

Refitting

At the same time, another officer of the Italian special unit, Lieutenant Licio Visintini, himself a veteran of previous submarine incursions against the “Rock”, learned about the Olterra and conceived the idea of a secret mother ship for the maiali. Maiale (literally “pig”) is the Italian nickname for the human torpedoes. Under the pretext of raising the ship to sell it to a Spanish owner, a team of members of the Decima, disguised as Italian civilian workers, took control of the tanker. The ship was towed to Algeciras, where “repairs” were started. The Italian Navy personnel were helped by two civilian members of the crew. They had remained on board the half sunken oiler along with a Spanish guard for more than two years, in order to protect the rights of the Italian company which owned the Olterra. Once at docks, some of Olterra's cargo holds and a boiler room were modified by Visintini men into a workshop for the assembling and maintenance of human torpedoes. An improvised observation post was also mounted on the forecastle to watch the Bay of Algeciras and the Allied ships at anchor there. A scene of civilian sailors working to overhaul the ship was meanwhile set up for the outsiders, in order to deceive both British and Spanish authorities. The torpedoes (in spare parts) and other equipment were smuggled into Spain by men of the Decima under the pretense of being materials for the ‘works’ on board the Olterra. Finally, a sliding hatch was open with a cutting torch six feet below the waterline. This would be the exit door of the manned torpedoes, which would launch their attacks from the flooding bilge, right beneath the workshop. The special unit in charge of the operations was dubbed Squadriglia Ursa Major, after the constellation of the same name.