Yugoslav minelayer Zmaj

The Yugoslav minelayer "Zmaj" (Dragon) was built in Germany as a seaplane tender for the Royal Yugoslav Navy in 1928–1930. She does not appear to have been much used in that role and was converted to a minelayer in 1937. Captured by the Germans when they invaded Yugoslavia in 1941, the ship was renamed and redesignated as an aircraft tender and later as a troop transport, before she was rebuilt as a minelayer in 1942. laid one minefield in 1943 that sank two Allied destroyers and badly damaged a third in the Aegean Sea. was also used by the Germans to evaluate the shipboard use of helicopters for reconnaissance purposes. She was sunk by Allied aircraft in 1944 at Samos and scrapped in place after the end of World War II.
Description.
Background.
The Royal Yugoslav Navy operated a series of seaplane bases on the Dalmatian coast before World War II and decided that it needed a ship to transport seaplanes between them and to rescue downed aircraft after operations as had been common during World War I. It decided on the smallest possible ship that could carry supplies and spare parts for ten seaplanes, and placed the order with a German shipyard. According to the naval historian Zvonimir Freivogel, the Yugoslavs may have chosen a German shipbuilder because the Germans may have subsidised part of the cost, and due to differences between Yugoslav naval aviators and their French and British counterparts regarding the size and role of the new ship.
General characteristics.
"Zmaj" was long overall. She had a beam of and, at deep load, a draft of . She displaced at standard load. Her two propellers were powered by a pair of eight-cylinder, four-stroke MAN Diesel engines that had a maximum output of . This was enough to propel her to a speed of . She carried a total of of fuel which gave her a range of .
She lacked a traditional funnel as her engine uptakes were taken up through the lattice mainmast amidships, which also served as the crane post. Her bridge was positioned in the centre of her raised forecastle, and her aft deck was low and wide to facilitate aircraft handling. She was fitted with a lattice aircraft handling crane with a capacity of . "Zmaj" was provided with six boats: two abreast of the bridge on either side; two abreast of the mainmast, one of which was a motor boat; and two dinghies on the stern. She was a poor seakeeping ship due to a combination of her high silhouette and shallow draft, which made her very susceptible to cross winds, and made steering difficult.
The ship was fitted with two single 55-caliber Škoda anti-aircraft (AA) guns, one each mounted on the forecastle and the stern. They had a maximum elevation of +85° and fired a shell at a muzzle velocity of . The guns had a rate of fire of 12 rounds per minute and had a maximum ceiling of . Four 67-caliber Škoda AA guns were mounted between the bridge and the mainmast in a twin-gun mount on each side of the ship amidships. They fired a shell at a muzzle velocity of . After her 1937 conversion to a minelayer, "Zmaj" carried 100 mines.
A single disassembled de Havilland DH.60 Moth floatplane was stored in the aircraft hold between the forward superstructure and the mainmast. Its components would be moved from the hold by the aircraft crane to the after deck where it could be assembled. Then the aircraft would be swayed over the side where it could be launched. The aircraft was removed from the ship when she was converted into a minelayer.
Construction.
"Zmaj" was built by Deutsche Werft in Hamburg, Germany. Due to the restrictions of the Versailles Treaty, she had to be built as an unarmed auxiliary. Her keel was laid down in 1928 and she was launched on 22 June 1929. While en route to Yugoslavia she had a severe engine room fire on 9 September 1929 off Flushing, Netherlands, and was forced to return to Hamburg for repairs. These took almost a year and she was accepted by the Royal Yugoslav Navy on 20 August 1930. She was finally commissioned in 1931 after she was armed and finished fitting-out in Kotor.
Service.
"Zmaj" appears to have been little used in her intended role; only her salvage of an upside-down Dornier Wal in the Bay of Kotor in 1936 has been confirmed. This may be why she was converted to a minelayer the following year. Following her conversion she made port visits to Piraeus and Istanbul, accompanied by the destroyer and the submarines and . "Zmaj" served as the fleet flagship in 1939 and witnessed the new destroyer run aground and sink in January 1940 at the narrow entrance to Šibenik harbor. Shortly before the German invasion of Yugoslavia on 6 April 1941 "Zmaj" laid defensive minefields along the Dalmatian Coast and off the main ports. These minefields may have caused the loss of the Yugoslav passenger ships SS "Karađorđe" and SS "Prestolonaslednik Petar" off Zlarin. "Zmaj" was captured in Split by the Germans on 17 April.
Renamed as "Drache" ("Dragon") by the Germans she was initially used in support of Luftwaffe seaplane units, but was redesignated as an aircraft rescue ship () on 7 August 1941. Her armament was increased by two and one anti-aircraft guns as well as racks for a dozen depth charges. She was transferred on 27 December to the Aegean and reclassified as a troop transport. "Drache" was modified at Trieste between April and August 1942 for service as a minelayer. Her existing armament was replaced by two , five and six 2 cm AA guns. She was equipped with four mine rails on her after deck that could accommodate up to 120 mines and another 120 mines could be carried internally. Her crane was replaced by two derricks and the lattice mainmast was plated over and resembled a funnel. A platform was built behind the funnel above the main deck.
"Drache" was recommissioned on 20 August 1942 and she was renamed "Schiff 50" on 6 November. She conducted a number of minelaying operations in the Aegean as well as some of the west coast of Greece. After the surrender of Italy in September 1943 she was used to carry troops to reconquer the island of Kos on 2–3 October (Operation Eisbär). On 8 October she was unsuccessfully attacked by the British submarine although her companion, the , was sunk. "Drache"s most successful operation was a mine barrage laid just east of the islands of Pserimos and Kalymnos to protect German troops during the Battle of Leros. The British destroyer and the , carrying supplies and reinforcements for the British forces on Leros, ran into this minefield on the evening of 22 October. "Adrias" had her bow blown off and "Hurworth" was sunk attempting to come to the aid of "Adrias". "Adrias", however, was eventually able to make it back to Alexandria. Two nights later the destroyer encountered the same minefield while carrying reinforcements to Leros. She hit a mine, broke in two, and sank in five minutes.
"Drache" was also used for shipboard trials with the Flettner Fl 282 "Kolibri" (Hummingbird) helicopter. She embarked the V6 and V10 prototypes for a period in 1942 and in January–February 1943. They used the small platform abaft the funnel to take-off and land. The "Kriegsmarine" (German navy) wished to evaluate their potential for anti-submarine warfare and mine reconnaissance, but visual detection proved to be possible only in clear weather.
The ship was attacked by Allied aircraft several times in 1943 and early 1944, but she was only lightly damaged on two occasions. Nonetheless her anti-aircraft armament was augmented during 1944. One quadruple 2 cm Flakvierling 38 mount was installed on each side of the bridge and she carried a total of thirteen 2 cm guns. Her 10.5 cm guns were exchanged for lighter guns to compensate for the increased top weight. However this proved to be insufficient to save "Drache" when she was attacked by several British Bristol Beaufighters of No. 252 Squadron RAF on the afternoon of 22 September 1944 while anchored in Vathy harbor on the Greek island of Samos. She was set on fire, exploded and sank two hours later; eleven of her crew, including her captain Joachim Wünning, died during the attack. She was scrapped in place after the end of the war.