Rolls-Royce powers world's first tug driven by natural gas engines

By Peter Pospiech at October 15, 2013 03:31
Filed Under: Company News, drive systems, Fuels & Lubes, LNG fuel, Shipyards, Workboats

Rolls-Royce has congratulated Sanmar Shipyard for the completion of the world's first gas powered tug, in a ceremony in Istanbul, Turkey, this weekend.

Sanmar has completed the first of two tugs for Norwegian customer Buksér og Berging, which each feature two Rolls-Royce Bergen C26:33L6PG engines fueled purely by natural gas (stored as LNG), with a combined output of 3,410kW (1,705 kW each) at 1,000 rev/min.The lean-burn engines operates on the Otto cycle with mixture compression and an external ignition source.A rich gas/air mix in a precombustion chamber is ignited and forms a strong ignition source for the very lean mixture in the cylinder for knock-free combustion. The engines are direct coupled to Rolls-Royce azimuthing Z-drives mounted aft in ASD configuration with controllable pitch propellers. Also, the new hull and propulsion system will achieve up to 20% higher thrust efficiency compared to standard designs. The LNG system is designed by AGA Cryo and comprises an 80m3 LNG tank, two cold boxes and bunkering system. The system is fully redundancy (i.e. no diesel back up is required). The tugs will obtain DNV Gas fuelled notation. 

View-cut of the natural gas propulsion drive-line

The first boat, named Borgøy, will enter service next month following a series of sea trials. It will be operated by Norwegian state oil company Statoil at its Kårstø gas terminal. The second tug, Bokn, will enter service in 2014.

1. Natural gas powered tug,Borgøy

The Rolls-Royce scope of supply includes the gas tank and supply system and two newly-designed 65t bollard pull US35 azimuth thrusters with 3,000mm ducted CP propellers in a new compact design with shorter stem length that ensure the tugs have rapid manoeuvring and positioning capabilities – which is essential for tug operation. 

Neil Gilliver, Rolls-Royce, President - Merchant, said: "The completion of this vessel is highly significant for Rolls-Royce, Sanmar Shipyard and Buksér og Berging. Gas is gaining in popularity as a maritime fuel, and its environmental credentials, combined with lower costs are seeing many operators select it over traditional fuels, across a range of ship types. Most of the world's tug fleets operate close to shore, where emissions regulations are most stringent. As LNG becomes more widely available, there is no doubt that many major ports will soon opt for this clean, lower cost and smoke-free fuel to power their tugs." 

The combination of Rolls-Royce gas engines and the latest thruster design, mean that the Borgøy and its sister vessel's CO2 emissions, will be around 30 per cent lower than conventionally-fuelled tugs. They will also comply with all known future emission regulations.


images: courtesy of Rolls Royce

Comments (2) -


S McKillop |     10/16/2013 1:03:05 PM #

i hope they will be as responsive as they hope,the trials will probably be extensive

michael koehler |     10/17/2013 12:45:10 PM #

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