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;