The Osvetnik class consisted of two submarines built for the Kingdom of Serbs, Croats and Slovenes – Yugoslavia from 1929 on – by Ateliers et Chantiers de la Loire in Nantes, France.

Both submarines were captured by Italian forces at the Bay of Kotor during the German-led Axis invasion of Yugoslavia in April 1941.

After refit, they saw service as experimental and training vessels with the Regia Marina as Francesco Rismondo and Antonio Bajamonti respectively.

In 1925, King Alexander visited the navy for the first time and several senior naval officers suggested to him that a submarine arm was needed.

In the middle of 1926, the British L-class submarine HMS L53 visited the Adriatic to familiarise Yugoslav naval officers with the class and undergo trials to demonstrate its capabilities.

The two British Hrabri-class submarines, based on a modified L-class design, were some of the first new acquisitions aimed at developing a naval force capable of meeting this challenge.

[4] In April 1927, two French submarines were ordered from the Ateliers et Chantiers de la Loire company (ACL) at Nantes.

[7] The Osvetnik-class boats had a partial double-hull with a straight flush deck which was slanted aft, and a raked stern.

The deck was wide enough to allow the crew to walk along it while underway, and was wider around the conning tower and main gun platform.

Both fore and aft of the conning tower on the port side, a folding telescoping radio mast was stored in a cradle.

The upper section of the second compartment was accommodation for the senior petty officers, along with their toilet, a cooking plate and small vegetable store.

The stern-most compartment contained the aft torpedo tubes, bunks for 14 crew, the potable water tank, electric steering machinery, and liquid oxygen and compressed air flasks.

[11] When submerged, the propellers were driven by two La Compagnie Générale d'Electricité electric motors generating a total of 1,100 shaft horsepower (820 kW).

The boats were also equipped with one semi-automatic Škoda 40 mm (1.6 in) L/67 anti-aircraft gun of the same type as those mounted on the flotilla leader Dubrovnik.

[5][9] Smeli was launched on 1 December 1928, the 10th anniversary of the establishment of the Kingdom of the Serbs, Croats and Slovenes, and was christened by the wife of the Yugoslav ambassador to France, Dr. Miroslav Spalajković.

Over the winter of 1928/1929, the crews for both boats underwent an intensive French language course aboard the submarine tender Hvar, and after additional specialist training they travelled to Nantes in two groups in early 1929.

Following these trials the boats were sent to the large French naval base at Toulon, also on the southern coast of France, where they were docked and the underwater parts of their hulls were cleaned.

[13] In 1932, the British naval attaché reported that Yugoslav ships engaged in few exercises, manoeuvres or gunnery training due to reduced budgets.