Newspaper article The Christian Science Monitor

Innovative Boat Buoyed by Bubbles Designer's Hunch about Aerated Water May Have Big Payoff in Global Competition

Newspaper article The Christian Science Monitor

Innovative Boat Buoyed by Bubbles Designer's Hunch about Aerated Water May Have Big Payoff in Global Competition

Article excerpt

SAILBOAT racers like to brag about their high-tech boats, designed on supercomputers and made from exotic materials usually found only on spacecraft.

Now solo around-the-world racer Steve Pettengill may have a breakthrough in sailboat speed that is more the result of a guess than millions of dollars of scientific effort.

Pettengill, sailing Hunter's Child, cut a "Venturi slot" on his 60-foot sailboat - a vessel he will pilot single-handed in the BOC Challenge around-the-world race beginning Sept. 17 from Charleston, S.C.

The slot is a gap of about 1/4 of an inch that goes completely across the bottom of the boat. A hole leads from the slot to the cockpit drain tubes on deck. As the boat moves forward, air is forced through the tubes and out the slot.

Pettengill explains the theory that the sailboat is dragging about an inch of "dead water" under the last third of the hull. This dead water is weight that must be moved with the boat. Since air is 1,840 times lighter than water, the idea is that the back part of the boat will move through a less dense medium - aerated water. The bubbles replace the dead water.

Lars Bergstrom, the boat's designer, based in Sarasota, Fla. tested his design this summer on a much smaller sailboat to try to get some measurements. A much earlier version of the concept seemed to work at high wind speeds when the boat would get up on plane.

"If it works, it would be good to use on more low-speed motor boats and a lot of different things," Bergstrom says.

The Venturi slot is not the only innovation on Hunter's Child, which is sponsored by Hunter Marine, an Alachua, Fla., sailboatmaker.

The bottom of the rudder is on a track and can slide from side to side across the stern while the top of the rudder is fixed at the center of the boat. In essence, it allows the rudder to tilt relative to the boat. …

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