These large submarines, the largest ever built by the Regia Marina, were capable of transporting 600 tons of material, and were specifically built for covert transport of goods of strategic interest (especially rubber) to the Far East. The need for this task surfaced during the war, and caused some of the existing oceanic boats to be adapted for this purpose.
The construction of the 12 boats was assigned to three shipyards: 6 boats to TOSI of Taranto (they had developed the project), 3 to the C.R.D.A. of Monfalcone, near Gorizia, and 3 to the O.T.O of Muggiano, near La Spezia. Due to the urgent need for their use, the first two boats were completed in less than one year, while the other 10 were surprised by the armistice of September 8th, 1943 while they were still on the slips in an advanced stage of completion. The Germans, who were in great need of such boats, captured the ones in Monfalcone and Muggiano and attempted to complete them, but none of these boats was actually completed.
The REMO was built by the TOSI shipyard of Taranto and was laid down on September 5th, 1942, launched on March 28 1943, and delivered to the Regia Marina, along with the ROMOLO, on June 19th of the same year.
Its operational life was, unfortunately, very brief as the boat completed only a few hours of navigation. After a period of testing and training, reduced to the minimum for the already mentioned urgency, on July 15th, 1943 (less than a month after it had entered service), the REMO under the command of Lieutenant Commander Salvatore Vassallo left Taranto for Naples.
At around 18:30, while the submarine was on the surface off Point Alice, it was hit by one of four torpedoes launched by the British submarine UNITED. Hit midship, the REMO sank in a few minutes in position 39°19’N, 17°30’E , 25 miles from the coast. Only four people survived, the three who were on the cunning tower (amongst them Captain Vassallo), and Sergeant Dario Cortopassi who was able to come up from the control room.
From information regarding spying activities, it appears that the Allies were aware of the departure from Taranto of the REMO (as well as the twin boat the ROMOLO, also lost three days later off Cape Spartivento, hit by bombs of a RAF aircraft), and had organized ambushes with submarines from Malta and airplanes based in Sicily (Comiso and Pachino).
All this because these Italian boats worried the Allies quite a bit, as much as to consider them a primary target because of what was being developed in Germany in the area of special projects (the so-called secret weapons), and their possible transfer to Japan following the Allied bombing of Peenemunde. Nevertheless, this possibility, although credible, is not reflected in the official Italian documentation.
It is sure, however, that at a crucial junction in the war, when the situation was collapsing (Italy was close to the fall of Fascism and less than two months from the armistice), there was great urgency to immediately utilize these boats. The Germans, who still did not have boats capable of long cruises (but were building them), pushed for having Italian boats in the Atlantic used between Bordeaux and Singapore, offering in exchange U-boats. The Italians could not comply because these submarines were needed to guarantee the traffic with Sardinia (lead, copper, antimony) at the time when the Allied offensive in the Tyrrenhian was on the increase. This explains the haste in which these boats, following delivery to the Navy, were sent to Naples.
The submarine REMO on the slip.
The submarine REMO in port.