Hockema Whalen Myers Associates (HWMA) developed the design for Dunlap Towing’s SIGRID DUNLAP as an evolution on the previously designed ocean tug PHYLLIS DUNLAP. While outwardly the two boats appear to be nearly identical, the new design incorporates the latest in equipment, environmental features and crew comfort.
At 121.5’ x 38.0’ x 18.2’, the new vessel will be put to work towing container barges from Seattle to Honolulu on a scheduled service for Alaska Marine Lines. The vessel is ABS and SOLAS classed with an ABCU endorsement for unattended machinery room operation. Redundant controls and monitoring equipment ensure the most automated and reliable platform possible.
The vessel is fitted with twin Caterpillar C175-16 engines turning at 1600 rpm that meet EPA Tier 3 and IMO Tier II standards. Reintjes WAF1173 gears provide the reduction to 120” 3 bladed propellers fitted in Nautican triple rudder Integrated Propulsion Units and incorporating Jastram independent steering controls. Engine controls and shaft brakes were provided by Propulsion Systems, Inc. A fuel capacity of 152,000 gallons provides ample range for Trans-Pacific crossings.
On deck the vessel is fitted with a large double drum Markey TDSDS-36 tow winch on the aft deck and an electric Markey DESW 32-20 hawser winch with anchor windlass on the bow. The tow pin unit was provided by McEvoy Machine.
Inside, the boat is fitted with three single staterooms and 4 doubles, all with individual Dometic climate controls for crew comfort. The boat is amply insulated with structural fire insulation as well as sound insulation, and includes a double layer Norac floating floor system over the engine room. The pilot house is state of the art, with Jotron communications systems and a Marine Controls Inc. alarm and monitoring package. The pilot house three-station control console features the latest electronics, including Simrad and Furuno navigation equipment by Marine Electronics Specialty Services, LLC.
“It is not common that we get the opportunity to revisit a previous design with the intention of refining every system to the best current technology. We enjoyed collaborating with Dunlap Towing and Hansen Boat Company to achieve this goal.” said Mike Whalen, project naval architect for the job. Initial feedback from the crew indicates that the boat is extremely seakindly, quiet and comfortable, indicating that the design objectives have been met.