Hudson Icebreaker

The Times-Union reports: Icebreaker clears path through Hudson River; Coast Guard crew keeps commerce flowing (includes photos and video).

Read more about the U.S. Coast Guard Cutter PENOBSCOT BAY (WTGB 107) at their site. (Click the picture on their main page to scroll through a number of cool photos.) Here's some technical detail:

The 140-foot icebreaking tugs are the most efficient icebreakers of their size in the world. They have a high horsepower-to-displacement ratio, which provides ample power to maneuver easily in ice. Two Fairbanks-Morse diesel engines provide 2,500 horsepower to a single shaft via a diesel-electric propulsion system. A unique hull design with a low length-to-beam ratio allows the cutter to break a wide track in the ice. The ship also generates a pronounced wake designed specifically for icebreaking. The combined hull design and horsepower enable the Bay class cutters to break up to 30 inches of solid freshwater ice without the need to “back and ram.” A hull air lubrication system, known as a “bubbler,” forces low pressure air from ports located along the lower hull and keel. Lubricating the hull with a mixture of air and water further reduces friction and improves icebreaking capacity.

Image from U.S. Coast Guard Visual Information Gallery.