Yugoslav minelayer Zmaj

The Yugoslav minelayer Zmaj (Dragon) was built in Germany as a seaplane tender for the Royal Yugoslav Navy in 1928–30. She does not appear to have been much used in that role and was converted to a minelayer in 1937. Captured by the Germans in 1941, she was renamed Drache (Dragon) and redesignated as an aircraft tender and later as a troop transport, before she was rebuilt as a minelayer in 1942. She laid one minefield in 1943 that sank two Allied destroyers and badly damaged a third in the Aegean Sea. Drache 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.

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.

General characteristics
Zmaj was 83 m long overall. She had a beam of 13 m and, at full load, a draft of 4 m. She displaced 1870 t 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 3260 shp. This was enough to propel her to a speed of 15 knots. She carried a total of 140 t of fuel which gave her a range of 4000 nmi. She lacked a traditional funnel as her engine uptakes were taken up through the lattice mainmast.

The ship was fitted with two single 55-caliber 83.5 mm Škoda anti-aircraft guns, mounted on the forecastle and the stern. They had a maximum elevation of 85° and fired a 10 kg shell at a muzzle velocity of 800 m/s. They had a rate of fire of 12 rounds per minute and had a maximum ceiling of 11300 m. Four 40 mm 67-caliber Škoda AA guns were mounted between the bridge and the mainmast in a twin-gun mount on each side of the ship abreast the aircraft hold. They fired a 0.95 kg shell at a muzzle velocity of 950 m/s. 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.

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 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 Dubrovnik and the submarines YUGOSLAV SUBMARINE Hrabni and YUGOSLAV SUBMARINE Smeli. Zmaj served as the fleet flagship in 1939 and witnessed the new destroyer YUGOSLAV DESTROYER Ljubljana run aground and sink in January 1940 at the narrow entrance to Sebenico 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 Karadjordje 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 (Flugzeugbergungsschiff) on 7 August 1941. Her armament was increased by two 2 cm and one 1.5 cm 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 10.5 cm, five 3.7 cm 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 20 x 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 HMS Unruly although her companion, the GERMAN MINELAYER Bulgaria, 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 HMS Hurworth (L28) and the GREEK DESTROYER Adrias, 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 HMS Eclipse (H08) 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 German Navy (Kriegsmarine) 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 8.8 cm 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 on the afternoon of 29 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 the commander Joachim Wünning, died during the attack. She was not salvaged and remained in place to be scrapped after the end of the war.