At 7:20 in the morning on 17 March 1942, the British submarine HMS Unbeaten surfaced in the Tyrrhenian Sea and her lookouts counted about a dozen Italian survivors swimming in the water. The ship that had been there minutes earlier was the Regia Marina submarine Guglielmotti, torpedoed while on passage to Cagliari. Before Unbeaten could pick anyone up, a patrolling aircraft forced her to crash-dive. When an Italian torpedo boat arrived hours later and searched the area, only one body was recovered. Of the 61 men aboard Guglielmotti, there were no survivors. The submarine had come home from the Indian Ocean to die a few miles from the Italian coast.
Guglielmotti was built by Cantieri Navali Tosi di Taranto and launched in 1938 as one of five Brin-class submarines - improved versions of the preceding Archimede class. She displaced 1,000 tonnes surfaced and 1,254 tonnes submerged, was 72.47 meters long with a beam of 6.68 meters and a draft of 4.54 meters, and had a partial double hull. Two 1,500-horsepower diesels gave her 17.3 knots on the surface; two 550-horsepower electric motors pushed her to 7.8 knots submerged. Surface range was 9,000 nautical miles at cruising speed. Her armament included eight 53.3 cm torpedo tubes, four forward and four aft, carrying 14 torpedoes total, plus a 100 mm deck gun originally mounted behind the conning tower. In 1940, under Captain Carlo Tucci, she was assigned to the 81st Squadron - part of the VIII Submarine Group based at Massawa on the Red Sea coast of Italian East Africa.
Her first war mission, beginning 21 June 1940, was a rescue. Another Italian submarine had run aground on the deserted island of Barr Musa Chebir in the Red Sea; her crew had scuttled her and taken refuge on the island. Guglielmotti left Massawa that day and reached the island the next. At 12:45 on 22 June, she took aboard all 21 survivors and returned to Massawa. For men who had been marooned on a barren Red Sea islet in summer temperatures that routinely exceed 45 degrees Celsius, the sound of a submarine diesel must have been the best sound in the world.
On 6 September 1940, patrolling south of the Farasan Islands for British convoy BN-4, Guglielmotti sighted two ships at around 15:00. One was too distant. The other, a 30-year-old Greek-flagged tanker named Atlas of 4,008 gross register tons, was straggling behind the convoy on passage from Abadan to Suez. Tucci closed to within 700 meters and launched two torpedoes. Both struck Atlas on the starboard side, opening a large hole through which oil poured into the sea. The crew abandoned ship and rowed toward Aden. Since the tanker did not appear to be sinking, Tucci ordered a third torpedo launched; it missed. A fourth hit her and broke her in two. Atlas sank. Three other patrol missions in 1940 - searches for convoys BN-5 and BN-7, a sweep for two merchant ships - produced no sightings, a reminder that naval warfare involved long stretches of fruitless search broken by moments of sudden violence.
By January 1941 it was clear that Italian East Africa would fall. Rather than lose the submarines based at Massawa to British capture, the Regia Marina decided to send them home - the long way. There was no way through the Suez Canal in British hands, so the boats had to circumnavigate Africa to reach the German-occupied French port of Bordeaux. Fuel tanks were enlarged. Torpedoes, ammunition, and non-essential equipment were removed. On 3-4 March 1941, Guglielmotti under Commander Gino Spagone left Massawa together with the submarine Archimede. They rounded the Cape of Good Hope, were refueled in the South Atlantic by the German tanker Nordmark, and reached Bordeaux on 6 May 1941 - a 66-day patrol covering more than 10,000 nautical miles. Archimede arrived the following day. Both submarines underwent extensive repairs; Guglielmotti did not return to operations until September 1941.
From Bordeaux, Guglielmotti sailed on 22 September 1941 for the Mediterranean, passed Gibraltar on 30 September, and reached Messina without incident on 16 October. She operated in the central Mediterranean for the next five months. On 17 March 1942, heading for Cagliari in Sardinia, she was intercepted by HMS Unbeaten - a British U-class submarine commanded by Lieutenant Commander Edward Woodward, who would become one of the most successful British submariners of the war. Unbeaten's torpedoes found their mark. The twelve survivors spotted in the water disappeared when Unbeaten was forced to dive. When the Italian rescuers arrived, the men were gone. Sixty-one Italian sailors - the full crew - were lost. Unbeaten herself would be sunk later in 1942 by friendly fire from an RAF aircraft, with all hands lost, a reminder that the undersea war consumed crews on every side with indifference. Guglielmotti's name is on the submariner memorials in Rome and Taranto.
Guglielmotti's Red Sea operational area was based on Massawa at 15.61°N, 39.45°E. The patrol where she sank Atlas was south of the Farasan Islands, roughly at 15.83°N, 41.83°E. Her final sinking location was in the Tyrrhenian Sea between Sardinia and mainland Italy, approximately 39.38°N, 11.30°E. Nearest airports today: Massawa International (ICAO: HHMS), Cagliari Elmas (LIEE, CAG) for the final sinking area. From cruising altitude over the southern Red Sea, the Farasan Islands appear as low coral outcrops scattered near the Saudi Arabian coast. The shipping lane between Bab-el-Mandeb and Suez remains one of the world's busiest. Clear visibility is most common October through April; summer brings heavy haze and heat.