In May 1941, the Decima MAS continued its attacks on the Port of Gibraltar. This time, the SLC pilots’ energy was preserved because they were flown over to Spain disguised as crew members and shipping company employees so that they wouldn’t have to go through the lengthy approach by submarine. Once they had arrived in Spain, they travelled overground to the Port of Cádiz, where the Italian tanker Fulgor had been detained since Italy joined the war.

On 15 May 1941, the transport submarine Scirè left the Port of La Spezia with the “maiali” on board, but without their pilots. After passing the Strait of Gibraltar on 22/23 May, Borghese reached the Port of Cádiz and overnight took on board the six SLC pilots who had previously been on the Fulgor: Decio Catalano and Giovanni Giannoni, Amedeo Vesco and Amelio Franchi (replaced by reserve Antonio Marceglia), Licio Visintini and Giovanni Magro.

Despite the successful deployment of the three SLCs on 26 May 1941, the B.G.3 mission failed due to technical problems and a good deal of bad luck in the last phase of the attack when an explosive charge that had been successfully attached to the hull of a ship became detached at the last second. All six SLC pilots reached the Spanish coast and were able to return to their base at Bocca di Serchio with the aid of the Italian Consul in Algeciras.

However, the mission B.G.3 still had some positive aspects: The British did not notice the operation and the element of surprise was not wasted. The use of the tanker Fulgor as a forward base on Spanish territory proved extremely useful and effective.