The Type 704 Rhön-class tankers are a series of replenishment oilers used by the German Navy to provide underway replenishment for its ships at sea. The two vessels in the class, and , were originally constructed for Libya by Kröger Shipyard in Rendsburg, West Germany as bulk acid carriers. They were acquired by the West German Navy in 1976 for conversion and entered service in 1977. The two ships are crewed by civilians. In 2019 it was announced by the German Navy that the ships are planned to be replaced in 2024. Design and description The Type 704 replenishment ships, originally constructed as civilian tankers, have a full load displacement of and were measured at and . They are long with a beam of and a draught of . They have capacity for of fuel oil and of water. The Rhön class are powered by one MaK 12-cylinder diesel engine turning one shaft with a controllable pitch propeller, rated at . This gives the vessels in the class a maximum speed of and a range of at . The ships are civilian crewed and have a complement of 42. The ships have two positions for portable surface-to-air missiles. Ship list Service history Two bulk acid tankers were ordered by Libya as Okene and Okapi from Kröger at their yard in Rendsburg, West Germany. Okene was launched on 23 August 1974 and Okapi on 13 February 1975. While still under construction, the two ships were acquired by the West German Navy in 1976 for conversion to naval replenishment tankers. Okene was converted by Kröger and was renamed Rhön for a mountain range in Germany. Okapi was taken to Bremerhaven for conversion and renamed Spessart, also a mountain range in Germany. Both ships entered service in 1977. On 1 April 2009, pirates operating off the Somalian coast mistook Spessart as a commercial tanker and opened fire on it before attempting to board the ship. The attack was repelled and the pirates were chased by several naval ships, eventually being captured by a Greek frigate. The pirates were handed over to the to be prosecuted. In July 2018, it was announced that both vessels of the class were laid up due to heavy maintenance required to get them back into service and that Spessarts engine would require a complete overhaul. New replenishment oilers The outdated tankers were planned to be replaced. The Bundestag