A 102-foot catamaran built almost entirely of carbon fiber set out last year to circumnavigate the globe using solar power alone. Tûranor PlanetSolar has made its way from Monaco to Miami and, at this writing, is already through the Panama Canal and well into the Pacific Ocean.
This extreme example shows the efficiency that can be achieved when a designer and yard get serious about losing weight. The trend is continuing as yards become better at building light and manufacturers develop more lightweight materials.
“We’ve never been able to build a boat that was too light,” said Michael Peters, president of Michael Peters Yacht Design in Sarasota, Florida. “To build a boat that a consumer would want, you can’t take enough weight out of it.”
The primary advantage of building lighter boats, whether power or sail, is efficiency. For powerboats, less weight means a builder can either make it go faster with the same power or make it run the same speeds as a heavier version with smaller engines. It also makes the boat more responsive to acceleration and maneuvers, which means it’s more fun to drive.
Weight in a boat — or the lack of it — has consequences. Heavier boats need bigger motors, larger fuel tanks and a heavier overall structure to support it all. Fuel is estimated to make up 15 percent of a boat’s weight. So lighter builds, with smaller engines, require less fuel capacity and a less robust internal structure. A side benefit of the lighter boat: Engines and fuel tanks take up less space, so there’s more interior space for designers to use.
With fuel costs ever climbing, efficiency relates directly to the bottom line as well. “What wasn’t an issue back in the ’70s, but is now, is fuel economy,” said Mark Lindsay, president of Boston Boat Works, which has been building lightweight hulls since 1975. “When fuel went from pennies per gallon to multiple dollars per gallon, it became a whole new concern.”
Ask any sailboat racing enthusiast and he or she will tell you that building light boats is nothing new. Additionally, many of the materials have been around for decades. Epoxy resin has been adopted for its toughness and flexibility over vinylester and polyester resins for years. Carbon fiber and Kevlar are popular materials that have been used to add stiffness and strength while saving weight. And coring, such as Baltek balsa and closed-cell foam materials such as Airex, Corecell and Nida-Core, which save weight and add strength and stiffness, were once the realm of the cutting edge but now are used much more often. Some fiberglass weaves such as S-glass and E-glass are more recent, but the bigger breakthroughs have come in construction processes. “Intelligent design and processing lead to better boats,” Lindsay said. “Materials are just easier to talk about.”
Peters said that, for many of his designs, a yard would bring in a structural engineer to work out the best lamination schedule. Hodgdon Yachts in East Boothbay, Maine, worked with an outside advanced-composite engineering company on its last two projects, boats for the Navy and for a private owner.
“We learned a great deal about what the concepts are and what goes into making a light boat with adequate strength,” said Kevin Houghton, senior structural designer at Hodgdon. The company also designed the boats in three-dimensional models from which all drawings were extracted, resulting in better-fitting components because of the tighter tolerances that were created in the process.
