SOUTH PORTLAND – Janet Acker heard the wind ruffle the shrink-wrap cover of her wooden home. The structure pitched from side to side. In the 8-by-11-foot living room, Acker asked her husband, “Can you think of any place on Earth you’d rather be?”

Their home – a 42-foot sailboat – lurched again. Barry Acker bent down to avoid smashing his head on a low passageway and told Janet there was no place he would like to be than right there – on the water, in the winter, in Maine.

The Ackers and 11 other yacht owners form a year-round colony known as “the live-aboards.” This aquatic lifestyle is fine in Waikiki – or Washington state, where the Ackers lived until last year. But winter in Maine is treacherous on land, and all the more so at sea.

Though spring means the harbor is no longer frigid, the live-aboards anchor in a marina with an ice breaker. East Coast yacht owners routinely shrink-wrap their vessels in dry dock, but for live-aboards such as the Ackers, the opaque plastic sheeting acts as insulation. It also means they gaze at the world through a cloudy filter, like a soap-filmed shower curtain.

The year-rounders have electricity, plumbing and heaters. Some have primitive galleys, a hot plate and cooler.

Aboard the Windrifter, Janet Acker has whipped up dinner parties for 11 on the propane stove. She bakes pies and cookies in the microwave – which provides storage space for cereal boxes when not in use. When they cook together, the Ackers move like samba dancers, maneuvering in a space that barely accommodates two sets of hips.

On the 32-foot Encore, Nate Jones and Heather Michaud insist they never feel cramped in a 9-by-20-foot living space. They share a trapezoidal bed known as a V-berth, with water tanks stored underneath. The couple say the cozy sleeping area is especially romantic during harsh storms.

Jones and Michaud also enjoy the sound of icicles hitting the shrink-wrap. “Like missiles,” said Jones, who patches the holes with duct tape.

All the live-aboards are accustomed to questions from land-lubbers:

“Are you nuts?”

“Is this about money?”

“Where do you go to the bathroom?”

All swear they are not clinically insane. Even when the thermometer lingers below freezing – which in Maine is most of the winter – they say they love being at one with the ocean. After all, they point out, it’s only cold for half the year.

“I love weather,” said Anne French, who has lived with her boyfriend on the 27-foot Ice Princess for two years. “I really love it when the boat is just covered in snow.”

The full-time marine life definitely costs less than conventional living on shore. The live-aboards own their yachts, although some have steep mortgages. Mooring fees vary by length: The Ackers, for example, pay $5,600 a year for their berth at South Port Marine.

They also pay insurance and monthly electricity charges, Internet and cable TV costs. But they have no property taxes.

As for the bathroom, the vessels have toilets and showers. When the Ackers installed a new heating system last year, one vent produced an unexpected result: heated toilet seats.

The Ackers bought their sailboat with plans for long-term cruising. Barry was a school superintendent and Janet worked in software. To be closer to their families on the East Coast, they bought land for a retirement house in Maine. Then Barry was offered his dream job: running a boat-building school in Kennebunkport. Instead of renting or buying a house, they decided to live on their sailboat.

They have no children, and their marriage apparently does not require the frequent release of steam by one party or the other. Neither is claustrophobic, another essential in such a cramped space. Even before they shrink-wrapped, they were unfazed by the prospect of Northeastern winters.

“So it snows,” said Barry, 58. “So you shovel the boat.”

The Ackers shared shrink-wrapping duties with Jones and Michaud. The younger couple bought a 175-foot roll of thick plastic, and the Ackers purchased a sealing gun, a cross between a blowtorch and hair dryer. Stretching the plastic over wood frames, they fashioned front doors. Their decks became mud rooms where they could peel off snow-covered parkas and boots before they headed to their living space below.

Most mornings, Barry opens his shrink-wrapped door and heads down the dock to his car. He stops at the gym for a workout and shower, then goes to work. Janet, 40, is launching a chain of drive-through gourmet coffee shops and works by phone and laptop at the Ackers’ dining table.

Even seen through the shrink-wrap, her biggest distraction is the ocean and its wildlife. “The seals,” she said. “The loons. The mergansers and buffleheads and black ducks.”

The Ackers sleep in a queen-sized bed in their aft cabin. The ceiling is so low that sitting up abruptly can cause a concussion. The perpetual motion is soothing, they said, like drifting off to sleep in a cradle for grown-ups.

“It was really rock ‘n’ rolling last week,” Barry said.

Some nights, they take their dinghy and row three minutes to dinner in downtown Portland. Other nights, the live-aboards have impromptu gatherings among themselves.

“It’s a nice neighborhood,” Barry said, as if describing a condo complex.

The Ackers are planning shrink-wrap improvements for next winter – an actual window so the world will look less hazy.

Some days, as they hunker down in their snug home at sea, they have second thoughts about that retirement house. Maybe they will just stay shrink-wrapped.