'Toast' was the Italian final mission planned for implementation by the Mariassalto, the co-belligerent Italian naval special forces unit descended from the 10a Flottiglia MAS of the Italian Fascist state’s navy (April 1945).
The mission was designed to sink the aircraft carrier Aquila, a conversion from the transatlantic passenger liner Roma which was currently approaching completion at Genoa. For this, the Mariassalto party entrusted with the task were to make use of two British Chariot manned torpedoes as they had none of their own SLC equivalents available. On 18 April 1945 the destroyer Legionario, carrying two high-speed motor boats, each equipped to carry one Chariot, departed Venice for Genoa under the command of Captain E. F. J. Chavasse of the British Special Operations Executive and Capitano di Fregata Ernesto Forza, commander of the Mariassalto.
After the destroyer had made the passage round Italy, both 'Chariot' craft were deployed as planned, and managed to penetrate the defences of Genoa’s port, but found the hull of Aquila to be so encrusted with barnacles and seaweed that their magnetic charges could not be attached to it. The frogmen therefore placed the charges on the seafloor of the outer harbour mole, and the subsequent detonation damaged but did not sink the ship. All of the frogmen escaped safely. After this the German commander in north-western Italy did not implement the major plan for demolition of Genoa’s port into effect, and Aquila was therefore not sunk as a blockship in the harbour’s entrance.