The large new escort tugs, contracted by Norwegian operator Østensjø Rederi, will feature Wärtsilä dual-fuel (DF) engines integrated with a customized gas storage and supply system also supplied by Wärtsilä. The tugs, designed by Robert Allan Ltd in Canada, will operate primarily on LNG but the Wärtsilä DF engines provide the flexibility to select the most suitable fuel according to availability, price and local environmental restrictions.
The overall LNG system, which incorporates Wärtsilä’s unique LNGPac fuel system, a fully integrated gas handling system, and the Wärtsilä Gas Valve Unit (GVU), has been specially designed by Wärtsilä to accommodate the need for a compact solution. The tugs will be powered by 6-cylinder Wärtsilä 34DF dual-fuel engines. These equipment will be delivered during the first half of 2016.
“These are trend setting tugs in that they provide environmental sustainability through the use of LNG fuel. The flexibility of the dual-fuel engine technology also ensures a high level of operational security since the switch from gas to diesel can be made at any time without loss of speed or power,” said Carl Johan Amundsen, Project Manager at Østensjø Rederi. The company is a provider of offshore services and operates a fleet of 28 modern vessels.
The vessels are designed to have a bollard pull of 100 tons, and will operate at Statoil’s Melkøya terminal near Hammerfest, Norway. Wärtsilä and Østensjø have cooperated closely to develop the chosen LNG solution for these new vessels.