Motoscafo Armato Silurante (Italian: "Torpedo Armed Motorboat"), commonly abbreviated as MAS was a class of fast torpedo armed vessel used by the Regia Marina (the Royal Navy of Italy) during World War I and World War II. Originally, "MAS" referred to Motobarca Armata SVAN ("Armed Motorboat SVAN"), where SVAN stood for Società Veneziana Automobili Navali (Naval Automobiles Society of Venice)
MAS were essentially motorboats with displacements of 20-30 tonnes (depending on the class), a 10 man crew, and armament composed of two torpedoes, machine guns and occasionally a light gun.
World War I 
MAS were widely employed by Règia Marina during World War I in 1915-1918. Models used were directly derived from compact civilian motorboats, provided with petrol engines which were compact and reliable (characteristics which were not common at the time) . They were used not only in the anti-submarine patrol role, but also for daring attacks against major units of the Austro-Hungarian Navy.
A significant success came in December 1917, when an MAS boat managed to sink the pre-dreadnought battleship SMS Wien in Trieste harbor. The greatest success of Italian MAS was the sinking of the Austro-Hungarian battleship SMS Szent István off Pula on June 10, 1918 by a boat commanded by Luigi Rizzo. MAS boats later engaged in the Second Battle of Durazzo in October 1918.
Spanish Civil War 
Four units were transferred to the Nationalist Navy during the Spanish Civil War in 1938: Sicilia (LT-18), ex MAS 100; Nápoles (LT-19), ex MAS 223; Cándido Pérez (LT-16), ex MAS 435; and Javier Quiroga (LT-17), ex MAS 436.
World War II 
Italian MAS continued to be improved after the end of World War I, thanks to the availability of Isotta Fraschini engines. The MAS of World War II had a maximum speed of 45 knots, two 450 mm torpedoes and one machine gun for anti-aircraft fire. In 1940 there were 48 MAS500-class units available. Older units were used in secondary theatres, such as the Italian East Africa.
Notable war actions performed by MAS include the torpedoing of the Royal Navy C-class cruiser HMS Capetown by MAS 213 of the 21st MAS Squadron working within the Red Sea Flotilla off Massawa, Eritrea; and the failed attack on the harbour of Malta in January 1941, which caused the loss of two motorboats, one of them recovered by the British. Five MAS were scuttled in Massawa in the first week of April 1941 as a part of the Italian plan for the wrecking of Massawa harbor in the face of British advance. MAS 204, 206, 210, 213, and 216 were sunk in the harbor; four of the boats were in need of mechanical repairs and couldn't be evacuated. On 24 July 1941, MAS 532 torpedoed and crippled the transport Sydney Star, which managed to limp to Malta assisted by the destroyer HMAS Nestor. MAS 554, 554 and 557 also sank three allied freighters on 13 August 1942, in the course of Operation Pedestal, for a total tonnage of 28,500 tn. On 29 August 1942, a smaller type of MAS boat, the MTSM, torpedoed and disabled for the rest of the war the British destroyer HMS Eridge off El Daba, Egypt.
A flotilla of MAS served at German request as Black Sea reinforcement in their intended attack on Sevastopol in June 1942. The MAS squadron came under intense air attack from Soviet fighter-bombers and torpedo boats but performed well in the role. They sank the 5,000 ton steamer Abkhazia and disabled the 10,000 ton transport Fabritius, which was subsequently destroyed by Stuka dive-bombers. MAS boats destroyed troop barges and damaged Soviet warships. One MAS boat commander was killed in battle. One MAS was destroyed and three damaged by fighter-bombers in September 1942 during a heavy attack on Yalta. Italian sources claim that on the early hours of 3 August 1942, three MAS boats torpedoed and disabled the Soviet cruiser Molotov southwest of Kerch. Another flotilla of four MAS, the XII Squadriglia MAS, was deployed to the Lake Ladoga in april 1942 to support the siege of Leningrad. They claim the sinking of a Soviet gunboat of the Bira class, a 1,300 ton mecargo ship and several barges.
The obsolescence of small MAS became apparent during the conflict, and they were increasingly replaced by larger Yugoslavian E-boats built in Germany and local copies of them (classified "MS" - Moto Siluranti by the Regia Marina).
A type of anti-submarine craft, based on the MAS design, was developed by the Italian Navy in World War II. This was the Vedetta Anti Sommergibile, or VAS, equipped with a good number of ASW assets given her small size.
Cultural legacy 
- Naval Weaponry: Italy's MAS Torpedo Boats
- Brown, David (2002). The Royal Navy and the Mediterranean: November 1940-December1941, Volume 1. Routledge, pp. 147-148. ISBN 0-7146-5205-9
- Greene, Jack & Massignani, Alessandro (1998). The Naval War in the Mediterranean, 1940-1943, Chatam Publishing, pp. 253-255. ISBN 1-86176-057-4
- HMS Eridge (L68)
- M.A.S. and Midget Submarines in the Black Sea 1942-1943
- MAS operations on Lake Ladoga (Spanish)
- MAS, VAS, and MS
See also 
- Italian Navy site Pictures of MAS boats amongst other historical Italian ships
- "MAS, VAS and MS" , by Pierluigi Malvezzi in the "Regia Marina Italiana" website