HMS X2

HM Submarine X2 was an Italian Archimede-class submarine, originally named Galileo Galilei. She served in the Regia Marina before and during World War II, before her capture by the Royal Navy in 1940.

She was stationed in the Red Sea in June 1940 as a unit of the Italian Red Sea Flotilla. During a patrol, with Capitano di Corvetta Corrado Nardi in command, on 16 June 1940, she sank the Norwegian tanker James Stove approximately 12 miles south of Aden, following which aircraft from the cruiser HMS Leander carried out a search for her without success.

On 18 June, the Galilei halted with cannon fire the Yugoslavian cargo ship Drava, but as Yugoslavia was not yet at war, she let it proceed. The gunfire was heard by the anti-submarine warfare trawler HMS Moonstone and at 04:30 pm Moonstone sighted the periscope of Galileo Galilei and carried out an attack with two depth charges, though without damaging the submarine at the position 12.8°N, 45.2°W. The following day, after the British warship repeated its attack with depth charges, Nardi gave the order to surface and engaged the Moonstone with her guns. At the start of the action between the two vessels, the forward gun's sighting mechanism on the Galilei became unusable. The fast-moving Moonstone scored the first hit on the Italian boat after ten minutes, killing some men and wounding Nardi. The following hit killed the crew of the forward gun, including the First Officer. The submarine's aft gun jammed, and then another salvo from Moonstone killed all those on the conning tower including Nardi. Under the only officer left alive, though wounded, the young midshipman Mazzucchi, the Galilei continued the fight with the forward gun. However the British destroyer HMS Kandahar arrived, and Galilei surrendered. The submarine had lost 16 men; Nardi, four other officers, seven NCOs and four sailors. The submarine was then towed into Aden. Though the British side claimed that the submarine's codebooks and operational documents were captured intact by the Royal Navy, and revealed the exact position of other Italian naval units, Italian survivors (including Midshipman Mazzucchi) reported that every document was destroyed before surrender, and that no written operational orders were issued to Italian units, only an oral briefing between captains and the submarine command in Massawa before every mission The claim was reported only to cover the British intelligence activities in Italian East Africa.

After her capture, Galileo Galilei was berthed at Port Said and served as a generating station to charge the batteries of British submarines. She was commissioned into the Royal Navy in June 1942 as HMS X2 (later changed to P 711), and was operated as a training boat in the East. She was scrapped on 1 January 1946.