Rolls-Royce Power Systems has supplied mtu gas engines for an LNG-fuelled tugboat with a hybrid system, which is now in operation in
The 29m JMS Sunshine, with 65t bollard pull, considered to be the first LNG tug powered by a hybrid system with gas engines was designed and built by the Seatrium shipyard in Singapore. The Port of Singapore has committed to the Maritime R&D Roadmap 2030 with the aim of making it environmentally friendly and reducing energy consumption. Rolls-Royce supplied the two 16-cylinder mtu Series 4000M55RN gas engines and the gas regulating unit (GRU).
Chiam Toon Chong, Technical Superintendent, Seatrium Marine Services, said: “The handling of mtu engines is straight-forward, and user-friendly. Additionally, spare part availability and service support is excellent for the operation of tugs.”
Chew Xiang Yu, Head, Rolls-Royce Power Systems’ civil marine, Asia, added: “We are proud that we were able to contribute to Seatrium’s innovative project with our gas engines. The workboat market is one of our strategic business areas. The mtu engines were selected because they meet the demanding requirements of harbour tug operations – in terms of reliability, ease of operation, dynamic engine behaviour and low emissions.”
The mtu gas engines are already well below the limit values of current emission guidelines (such as IMO III) without exhaust gas aftertreatment. The particulate mass is below the detection limit and they emit only small quantities of NOx.
The hybrid system is particularly suitable for the load profile of the harbour tug: it enables very precise manoeuvring and a strong bollard pull when the full power is used. To achieve maximum thrust, the total power of the two azimuth stern thrusters is 4000kW. This is achieved by adding to the 1492kW each supplied by the mtu gas engines and 500kW of electric motor power on each shaft. The tug is equipped with a battery capacity of 904kWh. The battery power is used to absorb peak loads, for example during acceleration, to manoeuvre purely electrically in port and to supply the ship on board with electricity.
Rolls-Royce says its Power Systems division has already received orders for mtu gas engines as propulsion systems and on-board gensets for a total of 11 ships worldwide. These include ferries, tugs and government vessels. Two catamarans belonging to the Doeksen shipping company have been operating reliably with mtu gas engines on the North Sea in the Wadden Sea nature reserve since 2021. The Richmond ferry has been operating a commuter service on the Lake Constance drinking water reservoir in southern Germany since 2023. Operators and passengers have observed that the engines are quiet, produce no vibrations, no unpleasant odours and no black smoke.
Image: Hybrid mtu LNG powered tug ‘JMS Sunshine’ (source: Rolls-Royce)
