Marine Transmission Built Arctic Circle Tough

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1328 Racine St., Racine, WI 53403

MARINE TRANSMISSION BUILT ARCTIC CIRCLE TOUGH

Bowhead Transport's newest addition to its fleet, M/V Unalaq, will service the

Alaskan coast, north into the Beaufort Sea. Utilizing Twin Disc's MGX-5135 SC marine transmissions and EC300 Power Commander® controls, the shallow-draft landing craft will bring much-needed supplies to this remote area. This includes small, isolated villages far above the Arctic Circle.

Unalaq was built to function in Bowhead Transport's lighterage operations. The boat ferries cargo to and from an ocean-going barge offshore. Landing on a beach or maneuvering in a shallow bay, the vessel requires precise control, especially at slow speeds. This is where Twin Disc's innovative reduction gear with Express® control excels.

The MGX-5135 SC features the company's revolutionary QuickShift® technology that instantly delivers torque to the propellers when altering from neutral to anywhere from full ahead to full reverse. Shifting is fast and smooth, and its slow speed control is unmatched. With Twin Disc's controls, Unalaq's prop shaft speed can be adjusted on the fly from well below engine idle to wide-open-throttle, and its three engines' rpms can be synchronized.

The transmission on Unalaq will get a workout. Unlike a static harbor, ever-shifting shorelines call for an exacting helm. "Lots of control is great to have when we're headed onto a beach," said Jason MacDonald, Bowhead Transport marine operations manager.

"When we're dealing with wind, chop, and strong sideways currents—immediate response is critical."

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-2- The continuous duty MGX-5135 SC marine transmission, with a 2.57:1 reduction ratio, boasts a maximum power rating of 445 kW (597 hp) at 1,800 rpm. The unit comes standard with an SAE J617 housing #1 and flexible coupling for the 35.5cm flywheel. Also included is the electric GP-valve with manual shift override. Many options are available in the controls to customize operation for specific applications.

The 45m L x 12m W Unalaq has a freight capacity of 450 tons. With

460 sq. m of deck cargo space, the boat can accommodate a serious load. With its enormous

8m L x 7m W bow ramp, crew can easily load and discharge cargo. The vessel is powered by three Caterpillar C-18 ACERT engines and, when fully loaded, has a cruising speed of 9 kts. It was designed by Columbia-Sentinel Engineers of Seattle, Washington and built in

2014 by Nichols Brothers Boat Builders of Langley, Washington.

For 33 years, Bowhead Transport has provided annual common carrier marine transportation service using specialized vessels, from Seattle to the Arctic Slope of Alaska.

Due to ice, it has a very narrow sailing window of the final week of July through the second week of September. The company's website is www.bowheadtransport.com.

For more than 75 years, recreational boaters and commercial mariners have relied on

Twin Disc's rugged, yet cutting-edge products. The Racine, Wisconsin-based company manufactures control drives, PTOs, pump drives, thrusters, helm controls, the Express

Joystick System®, and over 100 transmissions, ranging from 35 to over 4,000 horsepower.

Contact Twin Disc, 1328 Racine St., Racine, WI 53403 USA. [email protected]; www.twindisc.com.