The Motosilurante CRDA 60 t (also known as MS boat) was a type of motor torpedo boat built for the Regia Marina during World War II. It was designed on the pattern of German S-boats — some early examples of which were captured by the Italians from Yugoslav Navy — to complement the faster but less seaworthy MAS boats.
It was two Motosiluranti CRDA that scored the single biggest success by fast torpedo craft in the Second World War, the sinking of British light cruiser . After the conflict surviving boats remained in service with the Marina Militare—the last ones being ultimately dismissed after almost 40 years of service, in the late 1970s.
History
Background
Italian motor torpedo boats, the MAS, were built like speedboats, sacrificing seaworthiness for speed and manoeuvrability; for example the MAS 500-class, the latest type at the outbreak of the war, had a double-stepped planing hull and could top . Wartime experience quickly showed MAS usage was heavily affected by sea conditions; the Regia Marina began searching for a more seaworthy alternative. The solution came with the acquisition of six captured Yugoslavian motor torpedo boats, built by Lürssen of Germany in the 1930s after the early Kriegsmarine Schnellboote S-2 design; the boats were re-designated MAS 3 D to MAS 8 D and pressed into Navy service. Though these early examples were slower than their Italian counterparts, the S-Boote were able to operate in rough seas, thanks to their rounded hulls.
Design and war service
The Cantieri Riuniti dell'Adriatico firm of Monfalcone was tasked with reproducing the boats domestically. The quickly developed new torpedo boat type was designated CRDA 60 t after its builder and displacement, and classed Motosiluranti (singular motosilurante, MS in short) by the Navy. The motosiluranti were of wooden construction, with steel reinforcements. Unlike the diesel-engined German S-Boote, they were powered by triple Isotta Fraschini Asso 1000 W18 petrol engines from the MAS 500, each producing . They displaced from 62 to 66 tons and had a top speed of . Armament consisted of two 533 mm torpedo tubes, two Breda 20/65 mod. 35 anti-aircraft cannons in single mounts or four in two double mounts, and depth charge racks.
Thirty-six vessels were completed from late 1941 to the Autumn of 1943, in two series of 18 boats each. The first series included hull numbers from MS 11 to MS 16, 11–16, 21–26, and 31–36; the second MS 51 to MS 56, 61–66, and 71–76. Some changes were made from series 1 to 2, most notably a raised bow, redesigned torpedo tubes closed by hatches, and the addition of a pair of MAS-type 450 mm torpedo launchers at the rear of the hull.
In August 1942, during Operation Pedestal (referenced in Italian sources as Battaglia di Mezzo Agosto) two MS boats—MS 16 and MS 22—sank, in a night action, the British light cruiser HMS Manchester off Cap Bon. This 11,000-ton cruiser was the largest warship sunk by fast torpedo craft of any nation in the Second World War. The next month two MS boats were used to infiltrate a party of 14 Italian marines behind the Allied lines in Egypt on 3 September 1942. The marines blew up a railway and an aqueduct before being captured.
During the Sicilian campaign there were a number of night actions involving Italian MS boats. An indecisive clash took place in the early hours of 13 July 1943 between the British destroyer HMS Tetcott escorting an LST in the process of landing Royal Marines on Agnone Bagni, north of Augusta, and MS 71 and MS 63, which were trying to insert Italian Army commandos behind enemy lines. The following night, MTB 655, MTB 656 and MTB 633 encountered and engaged MS 36 and MS 64 south of Messina. The Italian boats received no damage, while the British craft were slightly damaged by shore batteries. In what became one of the last surface engagements between Italian and Allied naval forces, the American destroyer USS Rhind, assisted by the USS Gherardi, sank MS 66 and disabled MS 63, in the course of a naval sweep west of Capo d'Orlando, Sicily on 3 August 1943. The damaged MS 63 managed to limp away after firing a torpedo at Gherardi.