Uskok-class torpedo boat

The Uskok class or Četnik class, was a class of two motor torpedo boats built for the Royal Yugoslav Navy (Jugoslavenska kraljevska ratna mornarica; JKRM) during the 1920s. They were built by the Thornycroft Company based on their existing class of 55-foot long Coastal Motor Boats, with British-designed 456 mm torpedoes as their main armament.

When Yugoslavia entered World War II due to the German-led Axis invasion of that country in April 1941, both boats were captured by Italian forces. They were commissioned in the Royal Italian Navy, although their age and condition meant they were only used for patrolling and second-line duties. The first boat sank near Mljet in 1942 when its hull failed, while the second one was discarded in September 1943 and was broken up after the war.

Description and construction
The class was based John I. Thornycroft & Company's existing class of 55 ft long Coastal Motor Boats. Some sources refer to them as the Uskok class, while others call them the Četnik class.

They measured 16.77 m in length, with a beam of 3.35 m and a normal draught of 1.3 m. Their standard displacement was 15 t, and they had a crew of five. They used two Thornycroft petrol engines driving two propeller shafts. The engines were rated at 750 hp, and were designed to reach a top speed of 37 kn, although a speed of 40 kn was achieved during sea trials in 1927. They carried 1.6 t of fuel. They were equipped with two 456 mm torpedo tubes, two Lewis machine guns and up to four depth charges. An auxiliary engine of unknown rating was installed for cruising.

Both boats were laid down on 15 September 1926, and launched in May 1927. They were commissioned with the Royal Yugoslav Navy (Jugoslavenska kraljevska ratna mornarica; JKRM) as TČ 1 and TČ 2, later being renamed Uskok and Četnik. Initial exercises with the boats were delayed to await the return of their commanding officer from training in the United Kingdom. There were also some concerns that the Mediterranean sun would warp their hulls, and precautions were put in place to cope with this should it occur.

Service history
At the start of the German-led Axis invasion of Yugoslavia, Uskok, Četnik and the eight Orjen-class boats were part of the JKRM's 2nd Torpedo Division in Šibenik. They were soon captured by Italian forces and commissioned in the Regia Marina (Royal Navy) as MAS 1 D and MAS 2 D, with "MAS" standing for Motoscafo Armato Silurante (Torpedo Armed Motorboat) and the prefix D denoting they were captured in Dalmatia. Due to their age and poor condition, they were only used for patrol and second-line duties. MAS 1 D was lost on 19 April 1942 near the island of Mljet after the rivets in her hull plating failed, and she sprang a leak and sank. MAS 2 D was redesignated MS 47 in July 1942, before being stricken from the MTB list on 1 September 1943 and declassed as ME 43. After the war she was found in Taranto in a "very bad shape", and she was eventually broken up in the early 1950s.