Rolls-Royce will supply the gas-shielded propulsion system for two new multi-purpose vessels (MPV) built by German shipyard Abeking & Rasmussen for Germany’s Federal Waterway and Shipping Administration (WSV)
The two ships will operate in the North and Baltic seas to respond to accidents, fires or disabled vessels.
Both ships will use a gas-electric propulsion system based on four medium-speed Bergen B36:45L6AG units from Rolls-Royce, each delivering 3,600 kW.
In addition to providing the engines and generators, Rolls-Royce will provide gas protection systems specially developed to allow the engines to remain safely operational in circumstances where, for example, the ambient air has been contaminated with explosive gases following a gas tanker accident.
Rolls-Royce project manager Christian Prinz said "Obviously, the engines are there to burn gas, but if gas gets into the combustion chamber in an uncontrolled way via the intake air, the engine [could] become unmanageable".
To overcome this, Rolls-Royce said the engine power output is adjusted in relation to the amount of gas in the intake air, meaning the more gas there is in the intake, the less gas fuel is fed to the engine via the gas control valves.
If the gas volume becomes too high, quick-response flaps shut off the intake of gas and air and the engine comes to a stop.
The vessels will replace their predecessors, Scharhörn and Mellum, after 46 and 36 years of service, respectively. The predecessor vessels were also powered by MTU-brand engines from Rolls-Royce.
The ship technology division of the Federal Waterways Engineering and Research Institute commissioned the planning, design, tendering and construction management of the two 95-m ships.
Both newbuilds are capable of reaching speeds over 15 knots and are equipped with emergency towing capabilities with a 145-tonne bollard pull, chemical tanks, an explosion-proof safety and container cargo hold, oil skimmers, oil-holding tanks and a separation room.
Rolls-Royce said each vessel is fully gas-protected. In the event of flammable substances in the air, the crew can switch the ship to gas-protection mode, and windows and doors will be sealed air-tight creating a citadel into which clean air is pumped. The resulting overpressure ensures that no more toxic air can enter.
Using gas engines is a result of a directive from the German Government requiring a massive reduction in emissions from government vessels. And by the end of 2020, a decision will be made as to whether a third, identical vessel should be built.
The two newbuilds are scheduled to go into service in 2023 and 2024.