Crowley Marine Services (CMS) took delivery of Nanuq, the first of two 153-ft., 10,192 hp enhanced tractor tugs from Crowley Maritime Corp. subsidiary Vessel Management Services
. Nanuq and her sister vessel Tan'erliq have been specially designed and developed for CMS under contract with Alyeska Pipeline Service Company for tanker escort operations in Valdez Harbor and Prince William Sound, Alaska.
Because of the intended service environment, these vessels were designed to demanding specifications as the most powerful cycloidal propulsion tugs ever built, capable of a bollard pull of 208,000 lbs., and a vessel speed of 14.5 knots. In sea trials, the vessel was found to deliver in excess of 210,000 lbs. of bollard pull and a top vessel speed of just under 16 knots.
Nanuq is the first of two Prince William Sound Class tractor tugs designed and constructed for Vessel Management Services (VMS), a Crowley Maritime Corp. subsidiary which owns and leases vessels to CMS. Nanuq is powered by two Caterpillar 3612 engines driving twin Voith Schneider cycloidal propulsion units.
Both vessels will be outfitted for tanker escort services, ship handling, firefighting and emergency and spill response in Alaskan waters. Design features include a hydrofoil-shaped skeg, welded steel construction
, transverse framing, wing tanks and ice belting. The naval architects for the project were Guido Perla & Associates. Nanuq was constructed at Dakota Creek Shipyard in Anacortes, Wash.