The most successful Romanian submarine in WWII- NMS Delfinul

At the beginning of the war, June 22ed, 1941 the Marina Regala Romana (Romanian Royal Navy) had only one submarine, the NMS Delfinul, stationed in Constanta (the main Romanian port and naval base), commanded by Cpt. Constantin Costachescu. Delfinul was built in Italy, at Fiume, launched on May 5, 1936 and commissioned in 1938.

On the other side, the Soviet ChF ('Chernomorsky Flot'=Black Sea Fleet) had 47 submarines. But the existence of this one Romanian submarine forced the Soviet fleet divert a lot of resources to anti-submarine duties. For this reason it was used very carefully, since its loss was almost irreplaceable.

Delfinul's fifth war patrol took place between November 2 and 7, 1941 and was the most successful. Its mission was to attack Soviet convoys coming from or to Crimea. On November 5, she spotted SE of Yalta a cargo escorted by a gunboat and a submarine hunter. Delfinul started to maneuver for the attack, managed to get into a favorable position and fired its torpedoes. The cargo Uraletz was hit and after two minutes it started to sink. The escorts were joined by other submarine hunters and airplanes and the hunt commenced. About 90 depth charges were launched against the Romanian submarine during the 10 hours of the chase. Finally, she managed to lose them and sail home. This attack forced the Soviets to increase the escort forces for their convoys and the number of patrol aircraft. There were many cases in the following weeks, when Soviet ships attacked supposed Axis submarines, when Delfinul was not in that area or even at sea.

The last, 9th, war patrol of NMS Delfinul, June 25 to July 3, 1942 was carried out in the area east of Yalta. On June 27 she spotted a Soviet convoy and took position to attack it. The escorts discovered and attacked her, they also joined by patrol airplanes. Between 4:26 and 15:31, Delfinul 'received' 240 depth charges. The next day, she was on the surfaced when surprised by a Soviet airplane. Several machine-gun and cannon rounds damaged the rudder. On July 1st, she was again discovered and hunted for 13 hours. The crew counted 328 depth charges. They only got away after releasing debris and Diesel fuel through the torpedo tubes. As she returned home, Delfinul started general repairs and remained that way, until the end of the war. It was confiscated by the Soviets after August 23, 1944 but was returned to Romania after long time, damaged.

Specifications NMS Delfinul:

Built in Italy, at Fiume, and launched on May 5, 1936

Displacement (srf/sub tons): 640/886

Dimensions (L*B*D feet): 225'0*19'6*12'0
Propulsion: 2*800hp Sulzer diesels and 2*400hp electric motors

Speed (srf/sub knots): 14/9
Range (srf/sub n/miles@knots): 2,000@12/un known
Diving depth (meter): un known

Complement: 40 officers and enlisted

Torpedo: 4*21" (533mm) bow torpedo tubes, 2*21" stern torpedo tubes, total of 6 torpedoes
Mines: none
Armament: 1*4 inch main deck gun