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MIT designers take different tacks for America's Cup

MIT technology is once again driving the quest for speed on the water in the ancient art of sailing.

Two of the three American syndicates vying for the honor of defending the America's Cup have MIT ocean engineering department expertise represented in the design of their boats.

Professors Paul Sclavounos and Jerome Milgram have different ideas about what combinations will yield the fastest boat under all conditions.

Professor Sclavounos, a member of the Young America/PACT 95 design team, described the innovative winged rudder on Young America as the innovation of this America's Cup. "The data out of our computer tell us it will really increase boat speed," he said.

Professor Milgram, design director of Mighty Mary/America3 (A3), has a radical "whale's tail" design for the keel, the bulbous stabilizing element attached to the bottom of a racing yacht's hull, and a very long, 13-foot rudder.

While Professor Milgram agrees that rudder wings show enough promise to be worthy of a full-scale experiment, the evaluations and tests by A3 indicated that gain or loss was small either way.

The two boats have set different priorities. A3 has concentrated on improving light-air capabilities after being the clear winner in heavy conditions in 1992. (Professor Sclavounos, now with PACT 95, was responsible for the research on rough seas that aided the A3 effort in 1992.) PACT 95, on the other hand, has concentrated on performing well in rough water.

Professor Sclavounos and his cadre at MIT are also responsible for a computer program called Ship Wave Analysis (SWAN), which allows measurement of the water flow around a ship's hull. Being able to measure the performance of a boat in waves allowed them to test hundreds of hull designs by computer simulation. He said a one percent difference in speed translates to one minute on the race course.

Two weeks ago, the veil of secrecy around the ships' designs was dropped and the America's Cup contenders showed their keels, which are also known as bulbs. This was done to alleviate the intelligence and counterintelligence subterfuge that had grown as technology assumed greater importance. The results surprised many.

New Zealand, which has been steamrolling the foreign competition (the challengers) and was thought to have some new secret appendage, has a rather conventional design, including its bulb. According to Professor Sclavounos, it shares the "minimalist" approach with PACT 95's Young America. The most visible design difference is that New Zealand has large "unswept" winglets extending straight out from the bulb, whereas Young America has "swept" winglets angled toward the stern of the boat to allow kelp to slide away.

A3 and Australia were described as more "maximalist" by Professor Sclavounos. Professor Milgram agreed that they are a little more exotic, but only because of their appendages. A3 has a very long rudder-at 13 feet it was the maximum allowed. Initially, it also had the first-ever all-women's team, which has now been joined by tactician Dave Dellenbaugh.The women, while top-notch athletes and dinghy (small boat) racers, have not had experience in big-boat racing, which offers different challenges.

"As designers, we needed to accommodate to a less experienced sailing team," Professor Milgram said. "We designed a deeper rudder to be efficient at the unusually large rudder angles these particular sailors seemed to need to steer well. Mighty Mary, with its sleek narrow hull and relatively small keel, has terrific maneuvering, but keeping it aimed correctly is a challenge.

"We have a radical bulb, " he said. "It's short, shaped like a whale's tail. It has the best faring of winglets to keel, we think. Whales do their tails very nicely-they've had so long to evolve."

Since two designers formerly with A3 went to Australia this time, it is not surprising that the boats would more closely resemble each other. The Australian team is headed by John Bertrand, who won the America's Cup in 1983 and is a former student of Professor Milgram and a 1972 graduate of MIT.

"We've been thinking we should charge Australia a copyright fee," Professor Milgram joked. "But we're a lot stronger. Remember, New Zealand and A3 are the only boats remaining which haven't nearly sunk," he added, referring to the sinking of Australia's new boat. Pushing the envelope of design for speed has made many boats more fragile than in the past.

The third syndicate-that of Dennis Conner-has relatively little technology in its program. Its bulb has an unusual dip in the middle, which is difficult to see from the photo angles that were permitted at the unveiling. It is the slowest boat by all reports, yet continues to surprise with wins and brilliant tactical sailing.

So how much of the art is intuitive and emotional, and how much is technology? Both are needed these days, say the experts.

"A difficult challenge is getting the fruits of the science put into practice," Professor Milgram said. "The sailors need to learn to coordinate their intuition with the technical findings, and the scientists and engineers need to learn to make the boat perform optimally when the sailors are using their intuition."

For example, he said, the sailors like the feel of the boat at excessive heel angles. Heeling is when the boat leans far over to one side, bringing the center of gravity higher and thereby slowing the boat. The designers are thus pressed to distribute the weight in the boat for less than the optimum heel stability. This robs the sails of power. It takes time in the office and on the water to bring all elements together to the point where the crew is comfortable sailing a boat going as fast as it can, he said.

The entire effort is a massive system project involving management, fund-raising, science, technology, and most importantly, the skills of the team on the water, Professor Milgram said. Although science and technology can improve the overall result, it adds to the overall time required to do the project. If the managers of the projects started sooner, it would greatly increase their chances of success, he said.

Professor Milgram thinks that good sail shapes, good sail control and good sailing will decide the winner. Since most of the boats' hulls are similar to the A3 Cup winner of 1992, he thinks that boat design will be less of a factor this time. Professor Sclavounos, with a grin, said, "We'll see."

A version of this article appeared in MIT Tech Talk on April 26, 1995.

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