Tug owners are starting to use LNG for tug fuel, especially when the vessels are dedicated to escorting LNG carriers

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Wed 19 Dec 2018 by Martyn Wingrove

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​LNG-fuelled tugs are being built at shipyards in Singapore and China for Asian operations. Two tugs were delivered in 2018 in Singapore after they were constructed by Keppel Singmarine: Maju Loyalty entered service in July as an azimuth stern drive (ASD) tug, built for Maju Maritime, which is a joint venture between Keppel and Royal Boskalis Westminster.

It was designed by Keppel O&M for terminal and harbour operations, with an overall length of 32 m, breadth of 12.5 m and bollard pull, ahead and static, of 73 tonnes. Maju Loyalty’s propulsion and power comes from a pair of Niigata dual-fuel engines of 6L28AHZ-DF type, which drive two steerable and azimuthing, fixed-pitch propellers.

Maju Loyalty was the second dual-fuel tug that Keppel Singmarine delivered for Singapore operations, as in May 2018 it handed over the LNG-fuelled tug, KST Liberty to Keppel Smit Towage, which is a sister company to Maju Maritime. This is also an ASD tug for terminal and harbour operations, with 65 tonnes of bollard pull.

More LNG-fuelled tugs are being built for Singapore operations. In China, PaxOcean Engineering is constructing dual-fuel terminal tugs for PSA Marine. It laid the keel for the first of these LNG-powered harbour tugs, known by its hull number PX1098, at its facility in Zhuhai, China, on 23 November 2018.

Both tugs are expected to be delivered by the end of 2019. To meet PSA Marine’s performance, stability and environmental leadership expectations, PaxOcean, selected Canadian naval architect Robert Allan in January 2018 to design these dual-fuel vessels.

PaxOcean has built other diesel-powered harbour tugs in China for PSA Marine. In September 2018, it delivered two escort and berthing support tugs for the owner’s operations in Singapore. These azimuthing stern drive (ASD) tugs, PSA Thor and PSA Hulk, were built to the same Robert Allan design and classed by Lloyd’s Register.

Robert Allan designed an LNG-fuelled tug, of RAstar 3800-DF design, for Ningbo Zhoushan Port, China. This dual-fuel tug is under construction at Jiangsu Zhenjiang Shipyard for completion by Q3 2019.

It will be an ASD tug with a pair of Niigata 8L28AHX dual-fuel engines that will power two Rolls-Royce US 255 controllable pitch Z-drives. When this tugboat is delivered, it will have a bollard pull of around 80 tonnes and LNG storage capacity of 55 m³.

In Japan, Mitsui OSK Lines has two dual-fuel tugs under construction at Japan’s Kanagawa Dockyard Co. The first of these is scheduled for completion in February 2019 and the second tugboat is expected to commence operations in April 2019.

These will be operated by Nihon Tug-Boat Co, with the LNG fuel supplied by Osaka Gas. They will each have a pair of Yanmar 6EY26DF main engines. Yanmar is also supplying the LNG fuel tanks, buffer tanks and gas combustion devices that will be part of the gas fuel feed systems for the engines.

Robert Allan designs were used for three LNG-fuelled terminal tugs that entered service in the Arctic in 2017. Spanish shipyard Astilleros Gondán built three escort tugs – Dux, Pax and Audax – for Østensjø Rederi for operations at an LNG production centre and export terminal in Hammerfest, Norway.

These tugs were built to Bureau Veritas class and for operations in Arctic conditions all year round. They escort LNG carriers into and out of the terminal in temperatures down to -20˚C. They are RAstar 4000-DF design tugs with Wärtsilä dual-fuel engines. They can achieve a maximum free-running speed of 15 knots and can produce up to 107 tonnes of bollard pull.