BELFAST, Maine — The three owners of Nautilus Seafood & Grill on the city’s East Side know the restaurant business and, they believe, they know what both locals and tourists want.

Rosamond Peters, 34, her husband Ronald Mitchell Jr., 45, and Jenifer Oakes, 37, worked at Darby’s Restaurant & Pub on High Street. Peters and Oakes waitressed at the restaurant for many years, and Mitchell was its cook. And Peters and Oakes have known each other since they attended Belfast Area High School.

So launching Nautilus in the building on U.S. Route 1 that last housed the Fox Landing bar and restaurant is not exactly stepping into new territory.

“It was just time to do our own thing,” Oakes said Friday, as she and Peters prepared to meet with waitresses as Nautilus begins to hit its stride and approaches the tourism season.

What tipped the scales toward making the leap from Darby’s was a Chinese food run Mitchell made one day to another East Side business. He noticed that the former Fox Landing building was for sale.

“It’s just a cool building,” Oakes said, and that seems to be an apt word in two senses. Some of the knotty pine roof trusses and beams remain, but the carpet, walls and furniture are painted in muted blues and grays. The gray paint color was called vintage pewter, Peters said, with an affected haughty tone, but the choice achieves what they wanted, a kind of cool elegance coupled with an informal warmth from the wood.

At one point, the building housed a bar named Foxy’s, which Peters confessed she once thought meant it was a strip club. It was not.

The new owners assessed the location as having three business-friendly attributes: it is on Penobscot Bay, affording clear views; it’s next to the Belfast Harbor Inn, which provides a built-in customer base; and it is on the south side of Route 1, which means it’s easy for tourists traveling east to Bar Harbor to turn off.

The owners also decided to keep the menu simple, focusing mostly on seafood and steak. It also offers such appetizers as baked brie with homemade pesto, lobster crostini, fried calamari, steamers, and entrees with beef, lobster, haddock and chicken as centerpieces ranging in price from $16 to $21.

Mitchell is a distinctive cook, the women say, who earned a good reputation while at Darby’s.

“He’s just creative, and he had limitations at Darby’s,” Peters said. That restaurant has operated under the same owner, Jerry Savitz, since 1985, and its clientele has grown attached to the menu, both women said.

Nautilus also features a bar and serves Andrew’s English Pale Ale, brewed in nearby Lincolnville, and Lobster Ale, brewed by Belfast Bay.

“We have a good wine list,” Peters added, and a good selection of liquors.

The restaurant has 22 tables inside and 10 outside on the deck that overlooks the bay. Currently, it is open 3-10 p.m. weekdays and noon to 10 p.m. on weekends, but does not serve lunch.

“We want to do one thing, and do it really well,” Oakes said.

The women are touting the 3-6 p.m. happy hour featuring $1 off beers, Pabst Blue Ribbon for $2, $5 Margaritas and 25 percent off appetizers like oysters and steamers.