NMS Regele Carol I

NMS "Regele Carol I" was a passenger ship of the Romanian Maritime Service and later a warship of the Romanian Navy, serving as both minelayer and seaplane tender. She was completed and commissioned in 1898 and sunk in 1941, during World War II.
Construction and career.
"Regele Carol I" was initially built as a passenger steamer. She was completed by the Fairfield Shipbuilding and Engineering Company in Glasgow, Scotland, United Kingdom. The twin-screw ship was formally christened by the King of Romania and commissioned in July 1898. Shortly after her commissioning, her Romanian owners changed her fuel from coal to a mixture of half coal and half oil (two separate boilers). This conversion offered several advantages: the ship became slightly faster, the fuel consumption dropped by around half (60-80 tons of oil instead of 150 tons of coal required to cover the same distance) and the size of her crew was reduced. The steamer displaced 2,653 tons and her power plant had an output of 6,500 horse power, generating a top speed of 18 knots. She measured 93.2 meters in length, with a beam of 12.8 meters and a draught of 5 meters. In 1916, after Romania joined World War I, "Regele Carol I" was leased to the Imperial Russian Navy and converted into a warship. She served as both minelayer and seaplane tender, carrying one aircraft as well as 28 mines. She was also armed with two 150 mm naval guns. After briefly being renamed "Ion Roate" in early 1917 (she was also known as "Korol Carl" in the Russian Navy), she was returned to Romania at some point between 1917 and 1919. 
World War II and sinking.
At the start of "Operation Barbarossa" in June 1941, "Regele Carol I" and two other Romanian minelayers ("Amiral Murgescu" and "Dacia") laid a flanking barrage of mines off Constanța for the protection of the port. In October 1941, these mines sank the Soviet M-class submarines "M-58" and "M-34".
On 7 October 1941, "Regele Carol I" took part in a large-scale minelaying operation off the Bulgarian coast. The so-called "Operation Varna" consisted in the minelaying of the Bulgarian coast by the Romanian minelayers , "Regele Carol I" and "Dacia", escorted by the Romanian s "Năluca", "Sborul" and "Smeul", the Romanian gunboats and "Căpitan Dumitrescu" (both of the same class) and the Bulgarian torpedo boats , "Smeli" and "Hrabri" (all three of the same class). On 10 October, "Regele Carol I" was sunk off Varna, Bulgaria, by a mine laid by the Soviet submarine "L-4".