At the time that Italy declared war, the Italian Royal Navy consisted of six capital ships.Numerically the Italian fleet was strong but there was a large number of obsolete units and the service suffered in general from insufficient training of crews. The shortage of oil precluded extensive operations. All Italian warships lacked radar. he most successful attack performed by the Italian Navy involved divers planting mines on British battleships in Alexandria harbour. On 19 December 1941, HMS Queen Elizabeth and Valiant were sunk in shallow water by mines planted by Italian divers.The Italian Navy had some success against Allied resupply attempts for Malta with aerial and surface attacks on the convoys.In the Atlantic thirty-two Italian submarines that operated in the Atlantic sank one-hundred-and-nine Allied ships . The Italian Navy even planned an attack to New York harbor in December 1942, but this plan was  never carried out. Italian submarines carried out trade with Japan.