CARNELIAN BAY, Calif. — Rivas have round, flowing lines that blend with their sides and curved windshields, Hall added.More than 4,000 people are expected to attend the public display at Sierra Boat Company from 10 a.m. to 4:30 p.m. Friday, Aug. 10, and 9 a.m. to about 4 p.m. Saturday, Aug. 10.Referred by Motor Boat and Yachting magazines as “the best boat ever made,” the twin-engine Riva Aquarama is the event's Marque Class entrant.“The boats are magnificently engineered,” said Marty Feletto, who hauled his Aquarama from Sacramento to Carnelian Bay on Tuesday. “They have American power, which supplies some real horsepower, and they're well thought-out, very safe. They perform admirably in all seas.“It's just the greatest thing there is in life.”While the Lake Tahoe Concours d'Elegance celebrates its anniversary, so does the Aquarama, which began production in Italy 40 years ago. There were 769 Aquarama built from 1962 to 1996. There will be 20 in Lake Tahoe this weekend, and more than a dozen other Riva models at the show as well.“In the packing order of the wood boat world, Riva is on the top,” said Feletto, who has owned six of them.Relatives of the designer, Carlo Riva, have traveled from Sarnico, Italy, to attend the show and will celebrate the designer's 90th birthday and his greatest vessel. It is the 170th anniversary of the Riva family building boats. Carlo Riva himself will be among 350 people and 150 Riva boats at another celebration in three weeks in Lago Iseo, Italy. A Tahoe-area contingent of 32, including Feletto and Hall, will be in attendance.“(Carlo Riva) designed all of the early Riva models, and it was really his style,” Hall said. “The Aquarama is a very complex boat. He is a trained engineer and also a brilliant designer. He combined all of those talents.“It's not only the aesthetics of the boat but how everything works on the boat. Gosh, the controls and all the little bits and pieces that are on the boat are elegantly designed pieces that he pretty much penned himself. I would say 90 percent of the essence of the boat is pure Carlo Riva.”The handcrafted 27-to 28-foot Aquaramas are valued from $300,000 to $1 million and are often owned by celebrities and rock stars — the home waters for the majority of them on the West Coast are at Lake Tahoe.‘My father who got the whole Riva thing going back in the late 70s,” Hall said. “We went to Europe in 1979 and got the Riva Ariston. Made the contacts and started bringing them in and brought in close to 20 boats in the early 80s and got the ball rolling ... Got the Riva fever going, if you will.“A lot of other clients went over and got boats and brought them to use and we became the experts on these boats on the West Coast.”An Aquarama named Zoom competed with a legion of offshore boats in a 1972 race from Monte Carlo to London. The Riva came in second.In honor of the storied boat, the Riva Club USA will circumnavigate Lake Tahoe on Sunday in an event dubbed “Zoom.”The full boat lineup, complete with photographs, owner listings, boat descriptions and histories, are on the website www.laketahoeconcours.com.