Motoscafo Armato Silurante Commonly abbreviated as MAS were classes of Italian torpedo boats developed in 1915 and used in World war 1 and World War 2. Originally "MAS" referred to motobarca armata SVAN, where SVAN stood for Società Veneziana Automobili Navali ("Naval Automobile Society of Venice). They were Typically crewed by 10 men (depending on the class) and were armed with two torpedoes machine guns and occasionally a light gun (47mm was the most common). During WW1, they were used with great Success against the Austro-Hungarian empire, two of the greatest successes were the sinking of the Coastal defence ship SMS Wein in Trieste harbor and the Dreadnought battleship SMS Szent István by MAS 15 commanded by Luigi Rizzo. The MAS boats also took part in the Second Battle of Durazzo in 1918. During the interwar period four boats were sold to Albania but were seized during WW2 but later returned to Albania, The Spanish National Navy also used four Units. During WW2, the Obsolescence of the MAS boats began to appear despite this the MAS boats were used to great effect some notable ships damaged were the C class cruiser Capetown, The soviet navy cruiser Molotov which was disabled in 1942 and spent the rest of the war under repair, another notable ship disabled until the end of the war was the HMS Eridge which was deemed un repairable. A type of anti-submarine craft, based on the MAS design, was developed by the Regia Marine during the second world war this was the vedetta anti sommergibile, or "VAS" they were equipped with a lot of anti-submarine warfare equipment given their small size. The Italian Navy continued to use the Mas Boats into the early 1950s then were Subsequently retired.
MAS 15 was a MAS boat used primarily in WW1 she weighed 30 tons and was armed with 2 450mm torpedo tubes along with one 47mm gun and a 6.5mm small gun. MAS 15 entered service in 1916 she had a top speed of 11 knots. One of her most successful patrols involved her sinking the battleship Szent István becoming the only Motor torpedo boat to ever sink a battleship. The sinking of the Szent István was also the only battleship sunk in ww1 to be caught on film it also struck a major blow to the Austro-Hungarian navy coupled with the sinking of her Sister ship Viribus Unitis several months later crippled the already wounded Austro-Hungarian navy. MAS 15 today is preserved at the Sacrario delle bandire (shrine of the flags) which is inside the Vittorialle in Rome.