Scott Ferguson at the wheel of Il Mostro on its incredible 42-hour passage from Bermuda to Newport. When measuring speed, 15.11 nautical miles per hour is not impressive – unless you are on a sailboat.

Then, averaging 15.11 knots is fast. If a sailboat averages that speed over 635 nautical miles, the boat is very fast.

That’s exactly what Puma’s 70-foot Volvo ocean racer, Il Mostro, did on the return home from the Newport to Bermuda race last month.

Jamestown naval architect and premier mast designer Scott Ferguson witnessed the feat firsthand. He was a crewmember on Il Mostro when the boat made the passage.

“It was an incredible experience,” Ferguson said. “I was hired as a consultant to the design team. Puma wanted to use the trip back to Newport as a training exercise for the boat and crew, and I was invited to go along.

“I love racing sailboats. The routine of standing watches and participating as a crewmember on a prestigious boat like Il Mostro is exhilarating. It’s sailing at its best.”

Ferguson arrived in Bermuda on Tuesday, June 22, during the afternoon.

“The skipper, Ken Read, said the conditions looked good so they intended to leave that night to return to Newport. As it happened, the conditions were perfect. It’s something that happens once in a lifetime,” he said.

Ferguson said he did not have the exact time, but it was within minutes of 42 hours.

“We departed Tuesday, June 22, at 11:30 p.m. EDT just outside the official finish line off St. Georges, Bermuda,” he said. “Boats coming from Newport were still finishing the race. We completed the passage between Brenton Light and Beavertail on Thursday, June 24, at 5:30 p.m.”

The average speed for 635 nautical miles was 15.11 knots, he said.

“We started in light breezes blowing from 6 to 9 knots, and executed one or two jibes,” Ferguson said. “Then, we were on port tack for the entire passage. Sails, food, gear and equipment – everything was stacked on the port side of the boat. The wind was fairly light for the first half of the trip, averaging between 10 and 15 knots. A few squalls got the winds up a few times over 25 knots.”

The true wind angle was between 90 and 110 degrees for most of the trip, Ferguson said, adding that at this angle, the boat speed is about equal to the wind speed.

“The winds increased as we approached Newport with the typical Southwest winds that precede a front,” he said. “We arrived just hours before the front passed over Newport, bringing a few thunderstorms and not much wind behind it, so the timing was perfect. The weather routing software is amazing and predicted everything very well. We did not plan on cutting it so close to the front, but we got stuck in customs on the way out which delayed our departure by three to four hours.”

Ferguson said it took him a while to get used to driving the boat.

“We left Bermuda in the dark and I had never spent any time on the vessel,” he said. “But by the end, I was comfortably catching and surfing waves. At times, we reached speeds over 20 knots. These boats are incredibly well behaved, and track well, as the rudders are big enough [in these conditions] to always feel in control.”

Ferguson added that the conditions were close to perfect for the entire trip; otherwise, they would not have made such good time.

“Sailing doesn’t get any better than that,” he said.

He should know. He earned a bachelor’s degree in naval architecture from the University of Michigan and managed the mast design for BMW Oracle Racing USA-717, the boat that brought the America’s Cup back to America.

Ferguson has also helped to design some of the fastest racing yachts in the world. The bulk of his business is America’s Cup racing, and his area of expertise is in mast design.

When asked what makes his masts so special, he smiled and thought for a moment before answering.

In laymen’s terms, aerodynamics, weight, stiffness and materials appear to be the fundamental elements of importance in the design of winning sailboat masts.

A comprehensive answer is so complex that the need for a degree in nautical engineering might just be necessary to understand even the basics to developing a winning formula.

To put the speed of Il Mostro’s return trip in perspective, the boat came in second in the race to Bermuda, which was won by Speedboat, Alex Jackson’s maxi 100-footer. The race took just over 59 hours to finish, averaging 10.76 knots.

Granted, the winds were light to moderate and the crew of 25 never reefed the boat, so the race went down in the history books as slow. The record for the “open” division in the Newport to Bermuda race is 48 hours, 28 minutes and 31 seconds – or, 13.09 knots, set by Morning Glory in 2004.

That was not the case for Il Mostro’s return trip to Newport, however. At 42 hours, the boat was much faster, with a 15.11- knot average.

Scott Ferguson is the owner of Scott Ferguson LLC, a naval architectural firm specializing in the design of grand prix yacht racing spars.

He and his wife, Kim, live in Jamestown with their two daughters, Sydney, who will soon enter her junior year at Wheaton College and Kirsten, who just graduated with a B.S. in business from Babson College.