During the Second World War, the Royal Romanian Navy operated a total of 9 submarines: three fleet submarines and six midget submarines. These vessels fought on the Axis side during the war. Only two of them survived the war and continued to serve in the Romanian Navy until the 1960s.
Background
The first submarine ordered by Romania was part of the 1912 naval program. She was ordered from Italy, along with the four Vifor-class destroyers, however she was requisitioned by the Italian authorities in 1914 and never delivered to Romania. A second order, for a class of three 340-ton submarines, was placed in France during the First World War. However, these too were requisitioned by the French Navy and commissioned in 1921 as the O'Byrne class. These three boats became the first class of French submarines to be completed between 1919 and 1944.
Delfinul
The first submarine to be ordered and actually commissioned by the Romanian Navy was Delfinul. She was ordered in 1927 from the Italian naval base and shipyard at Fiume (today Rijeka, Croatia). A second boat of this class was also planned, but not laid down. She was completed in 1931, but was accepted by Romania as the country's first submarine only in 1936, after the many corrections required by the Romanians were completed. Delfinul had a surfaced displacement of 650 tons, which grew to 900 tons when submerged. The boat measured in length, with a beam of and a draught of . Her power plant consisted of two Sulzer diesel engines and two electric motors powering two shafts, giving her a top speed of on the surface and submerged. Her crew amounted to 55. She was armed with eight torpedo tubes (4 bow and 4 stern), one deck gun and one twin machine gun. After the 23 August 1944 coup, the submarine was confiscated by Soviet forces and commissioned as TS-3 on 20 October 1944. After a short career in the Soviet Navy, it was decommissioned on 12 October 1945. The submarine was eventually returned to Romania in 1951 and stricken in 1957.
Wartime achievements
Delfinul had a significant contribution to the Romanian victory during the 26 June 1941 Raid on Constanța. During her first sortie of the war, she spotted the advancing Soviet warships hours before they reached the Romanian port, enabling the port's defenses to be ready and alert upon their arrival.
On 20 August 1941, towards the end of her third sortie, Delfinul was missed with a torpedo by the Soviet M-class submarine M-33, four miles off Constanţa. The Romanian submarine swiftly counterattacked with her twin 13 mm machine gun, causing the Soviet submarine to submerge and retreat.
In the early hours of 6 November 1941, during her fifth sortie, Delfinul torpedoed and sank the Soviet 1,975-ton cargo ship Uralets four miles South of Yalta. The submarine was subsequently attacked by Soviet forces but she followed a route along the Turkish coast and managed to evade up to 80 depth charges, before safely arriving in the port of Constanța on 7 November.
Marsuinul
Marsuinul was designed by NV Ingenieurskantoor voor Scheepsbouw in the Hague. She was laid down at the Galați shipyard in Romania in 1938 and launched on 4 May 1941. She had a standard (surfaced) displacement of 620 tons, a length of 58 meters, a beam of 5.6 meters and a draught of 3.6 meters. Her power plant consisted of two MAN diesel engines and two electric motors, powering two shafts which gave her a top speed of 16 knots on surface and 9 knots in immersion. She was armed with one 105 mm naval gun, one 37 mm anti-aircraft gun and six 533 mm torpedo tubes (four in the bow and two in the stern). She was captured by Soviet forces after the 23 August 1944 coup and commissioned as TS-2 on 20 October. She was sunk at Poti on 20 February 1945 by the accidental explosion of one of her own torpedoes.
Wartime achievements
Marsuinul was commissioned in May 1943. She spent almost a year undergoing sea drills and tests, only being declared ready for action in April 1944. She carried out only one patrol mission, between 11 and 27 May 1944, along the Turkish coast, between Eregli and Trabzon, and near the Soviet port of Batumi. During her sortie, on 20 May, a Soviet submarine launched a torpedo at her, which missed. This was the second and last engagement between a Soviet submarine and a Romanian submarine.