The end of the Great War saw the Regal Marina come out of it with a new weapon: the MAS (Motoscafo Anti Sommergibile – Anti Submarine Motorboat). This weapon had given to the Italian Navy the most glamorous successes, such as the sinking of the battleships SZENT ISTVAN and WIEN, respectively, by MAS 15 and 9. By the end of the conflict, 422 MAS had been ordered; of these 244 were already in service, others would be completed in the postwar period, and many were canceled or sold to private individuals or completed as civil boats.
Between the two wars
The end of the war, however, didn’t interrupt the development of this weapon, which had revealed itself so effectively. Various prototypes were experimented with employing engines of various types, and finally, the much sought after high speed of attack was attained (the MAS during the Great War stayed, in general, well below the 30 knots of maximum speed).
The general design, however, remained the same as the MAS of the First World War. In 1931/32 the shipyard Baglietto, exploiting the experience acquired during the production, in 1926, of a unity for the French Navy in collaboration with the shipyards “Loire “, realized a prototype, the MAS-431, that summarized the best of the experiences gathered up to that moment.
Propelled by two gas engines FIAT of 1500 HP and equipped with a step hull (rédan), this vessel during tests reached about 45 knots of maximum speed in calm waters, with an excellent maneuverability, good seafaring and sturdiness. Another prototype built in the second half the 30s, but which didn’t give satisfactory results, was the STEFANO TURR. It was a large boat of over 60 tons of displacement that, besides dimensions notably superior to those of the MAS of the period, had the peculiarity of having four fast diesel engines, rather than gasoline ones. This experiment was an attempt to resolve the problem of gasoline flammability in the case, for instance, of hits aboard the vessel.
Unfortunately, the installed FIAT engines never gave satisfactory results in terms of reliability, so much that the unit, which had foreseen, of quite a few years, many characteristics of the best MS built during the war by the Germans, was removed from service and demolished in 1941. Failing this experiment, and with the international situation starting to deteriorate, the Regia Marina chose to lean toward the MAS derived from the prototype Baglietto. From 1936 to 1941, four series of MAS were built starting from the 431. The first series comprised 26 units, the second 25, the third 14, and the fourth 11. The base characteristics of these 76 MAS didn’t vary much between the several series. Displacement was of 23 to 30 tons, the engine was the excellent Isotta Fraschini Ace 1000 in various versions with a power output of 2000/2300 HP, and a maximum speed around 40-42 knots at full load. These MAS were equipped with two 450-mm torpedo launchers. The anti-aircraft armament had one or two guns with caliber ranging from 13,2 to 20 millimeters.
The war employment of the MAS showed, nevertheless, some defects mainly caused by the search, at all the costs, for very elevated maximum speeds. The price paid was in terms of unsatisfactory seaworthiness, especially in the case of less than ideal sea conditions. This was caused by the excessive lightness of the construction, and from the type of step hull adopted, which was designed to attain very elevated speed, but at the expense of seaworthiness. As a matter of fact, the MAS were notably difficult to operate in the case of rough seas, with serious risks to the safety of the crews.
In April 1941, while possible solutions to the problem were studied, the capture of what remained of the Yugoslav fleet provided the solution on a silver plate. Besides the other material, six torpedo boats of German construction were captured in the port of Cattaro. They were all of the type Ss 1, built by the shipyard Lurssen. These units, of about 65 tons, immediately proofed themselves in conformity with the requirements of the Regia Marina. In fact, the shape of their hulls allowed them to properly maintain high speeds even under not-too-ideal sea conditions. The shipyard CRDA of Monfalcone was therefore given the task to redraw the blueprints of these units and from these derive a new Italian project for a MS.
Thus was born the MS “CRDA 60 t.” which replicated, with minimal changes, the original German model. The model was immediately reproduced in a first series of 18 units, which entered service beginning in April 1942. This first series was followed by a second one of as many, of which the last unit was not delivered because of the armistice of 8th September. The MS of this type, even though inspired by an outmoded German model, was better fit for the long patrols in the Mediterranean than the MAS. Although not as fast, they surely had better seaworthiness and, due to the greater dimensions, they were more comfortable, better armed, and with greater range.
On the same hull of the ex-German MS, a small unit for anti-submarine patrol and coastal escort called “Vedetta Anti Sommergibile” or VAS was designed. Not as fast as the M.S, it had a powerful (for its dimensions) antisubmarine arsenal. The VAS was built in 45 units (of the 48 ordered) starting in 1942. Later, a new model was studied with a displacement around 90 tons, instead of the 68-70 of the first series. Six of the twelve units originally ordered were built.
These were the last units placed into service by the Regia Marina during World War II. The building programs of 1943 and 1944 foresaw the construction of quite a lot more units: 44 MS of the type “CRDA 60 ts.” in two following series, 30 MAS, 9 units derived from the German MS of the type S-26.
Some of these units had to be completed as gunboats, replacing the torpedoes with 37/54 guns and quadruple 20mm guns, to oppose, as much as they could, the fast Anglo-Americans units which usually mounted a superior armament. Besides these units, another two series of VAS were programmed: 12 ordered from Italian yards, and as many to be built by shipyards of occupied France. All these units belonged to the 90-ton type.
The MAS and the MS achieved notable successes during the war. It must be noted that, besides the sinking of numerous merchant ships, these units sunk the largest warship sunk by a torpedo boat in the period 1939/45. This was the English light cruiser MANCHESTER , sunk during the Battle of Mid-August by MS 16 and 22.
It also must be noted the sinking of the English destroyer LIGHTNING (Algerian coasts, March 12th 1943), the Russian submarine EQUOKA (Black Sea, June 19th 1942), and the serious damages to the English cruisers CAPETOWN (MAS 213 April 8th 1941) and Russian MOLOTOV. (MAS 568 and 573 August 3rd 1942).