PORTSMOUTH, R.I. – Looking for an isolated, rustic ocean oasis? Then the U.S. government may have a deal for you.

It’s auctioning the Hog Island Shoal Light, an isolated lighthouse about three-quarters of a mile northwest off the Portsmouth coast. Built in 1901, the white tower alerts passing ships to shoals near the entrance of Mount Hope Bay.

Federal law requires the U.S. government to first offer historic lighthouses at no cost to nonprofit groups such as local governments or preservation societies, according to the U.S. General Services Administration. If nonprofits aren’t interested, lighthouses are offered for sale to the public.

GSA officials say Hog Island Shoal Light is one of five lighthouses in Rhode Island, Maine and Maryland that are being put on the auction block.

The largest bid so far is $25,000, according to a GSA Web site. That’s chump change considering that bidding closed on the Baltimore Harbor Lighthouse at $260,000.

Of course, the 60-foot tall cast iron-and-brick lighthouse would make an unusual vacation home. It stands atop a granite caisson in the middle of passage between Portsmouth and Hog Island. There’s no yard, running water, plumbing or electricity.

The first floor is a galley topped by two floors for living quarters. The fourth floor is a workshop and the top is the lantern room.

Since the lighthouse remains a navigational beacon, interested buyers must allow the Coast Guard access so it can maintain the light and foghorn.

Sandblasting and painting the exterior could cost more than $300,000, said Keith Lescarbeau, whose restoration company has worked on several Rhode Island lighthouses.

“It’s got to be someone with a realistic idea of what it will take,” he said. “Unless it’s somebody who’s doing very well, maybe their own yacht and helicopter, I personally think it would be a long shot.”

Four people showed up at a Bristol Coast Guard station this week for a tour of the property. The trip was eventually canceled due to rough seas.

Prospective buyer Manny Silva, who operates a pub outside Boston, said the lighthouse “has a lot of potential.

“But I’ve got to get out there and have a look inside,” he said.