The newest car in the Rolls-Royce family, the $400,000 Dawn convertible is a big, beautiful boat. Powered by a 6.6-liter twin-turbocharged V-12 engine that makes 563 horsepower and 575 pound feet of torque, and weighing in at just under three tons, it is a street schooner designed to sail the Cote d’Azur.

Meant stylistically to recall the 1953 Silver Dawn drophead — the first Rolls-Royce vehicle built as Britain began to recover from World War II — the new Dawn is long and broad in the beam, with graceful lines that suggest sinuous, sophisticated strength.

On the wine country back roads, gliding between the faux-Danish kitsch of Solvang and the calculated small town charm of Los Olivos, the Dawn was a driving delight — powerful and pleasantly understated.

Rolls-Royce calls it “a sumptuous and sartorial slingshot of wood and leather,” and says the slingshot will accelerate from zero to 60 miles per hour in about 4.9 seconds.

As if to underscore the vast strength of its V-12 engine, the Dawn (like other Rolls-Royces) features a “Power Reserve” gauge instead of a tachometer. In an exploratory mood, I pressed the gas pedal down on a stretch of open road and watched the reserve drop from 90 percent to 10 percent. In short order, the Dawn crested 110 miles per hour without showing any sign of struggle, and without visible movement on the gas gauge. (The Dawn gets about 19 miles per gallon when driven judiciously on the highway, and around 14 in the city.)

Rolls-Royce asserts that the Dawn is the quietest convertible ever built, and as quiet as its hardtop Wraith. It features a six-layer fabric roof that, when raised, creates none of the wind noise typical of ragtop cars. The mechanism that lowers and raises the roof is so soundless that Rolls calls it a “silent ballet.”

Everything about the Dawn is stately and silent. Even the slowest of the fan settings is marked “Soft” instead of “Low.”

With the top down, the drive is a little noisier, and the enormous rear passenger area — fine, leather-bound acreage that includes its own seat warmers and coolers — is as windy as the back seat of a lesser car.

But Rolls insists it is quite safe. “Should the worst of circumstances arise,” the company says, the Dawn will instantly deploy a concealed “roll-over protection system” to protect car and driver.

The interior appointments are heavy on select woods, leathers and chrome. The upholstery in the model I drove was clad in a supple, sensuous Mandarin Orange leather that seemed almost edible.

Audiophiles will be pleased to know Dawn’s designers have included “the most exhaustively designed automotive hi-fi system ever developed.” A hidden microphone senses ambient noise and adjusts volume and tone accordingly.

The Dawn is a two-door, but its builders insist it is far from the typical “2+2” convertible that, like the Ford Mustang, Chevrolet Camaro, Buick Cascada or other soft tops, has two seats in front and a cramped afterthought instead of a back seat.

Ingress and egress are achieved through forward-opening “coach” doors of the kind once known on American cars as “suicide doors.”

They create a generous space as they swing open, and for the same reason are difficult to close manually. No problem: Press the button just forward of the front seats, and the doors swing gently shut.

The convertible was recently named Top Gear Magazine’s luxury car of the year. Robb Report recently blessed the vehicle with its 2016 design of the year award, saying it “redefines the notion of a true super-luxury Drophead.”

Rolls representatives said the company sold 4,000 cars last year, a third of those in North America. Around 80 percent of its vehicles’ purchasers are “new wealth entrepreneurs,” Rolls reps said, businessmen who made their own money and are happy to spend $400,000 on four wheels. Their average age is 47 — younger than one might think.

With the Dawn, they’d acquire one of the best automobiles ever built — and the bragging rights that go with it.