The Martha’s Vineyard Museum has extended its option to buy the former Marine Hospital property in Vineyard Haven for four months while it evaluates fund-raising sources for what could be a $20 million relocation and renovation effort.

Museum director David Nathans said this week that building on the enthusiasm of abutters, the Martha’s Vineyard Commission and of the community at large, the board of directors voted last Friday to extend an option that expired on Jan. 31 until May. He said the move signals the museum’s commitment to the site.

“If we didn’t think we were going to purchase we wouldn’t keep moving,” he said. “So all signals are go to take the risk to put that money out there.”

Mr. Nathans did not disclose the price of the option but said that if the museum decides to buy the property, it would count toward the final purchase price.

The museum presented its designs for the new property at a meeting of the Martha’s Vineyard Commission on Jan. 20. The plans include tearing down a 1938 brick addition to the building, renovating the existing structure and adding a 7,500-square-foot wing to house exhibitions. The museum would also clear-cut the Lagoon Pond-fronting lawn of the property to expose overgrown terraces, reclaiming a once prominent spot on the Lagoon coastline. Commission members were largely enthusiastic about the proposal.

The property, which is owned by Barbara St. Pierre, is currently listed for sale at just under $3.2 million. If the museum decides to buy the property, it could be as long as five years before it opens its doors in Vineyard Haven. Mr. Nathans said he expects a further one to three years of fund-raising and an 18 to 24-month building period that would include transporting much of the museum’s fragile collection. Still, Mr. Nathans cautioned that it was an ambitious schedule.

“The Museum of Fine Arts started thinking about their expansion for the America wing 15 years ago, started raising the money 10 years ago and it just opened two to three months ago,” he said. “For us to contemplate a year to three for fund-raising is optimistic in many ways.”

Two years ago the museum scrapped a $35 million fund-raising effort to relocate to a 10-acre property in West Tisbury, but that plan was plagued by a souring economy and a lukewarm response from the community. It’s a problem Mr. Nathans does not expect to encounter this time around.

“The neighbors want us, everybody seems to want us,” he said. “People seem to see it makes sense. Now the question is for those people who had expressed interest: We now need to change their expression of interest into enthusiasm.”

And dollars. Mr. Nathans said that in a single-phase buildout he expected the project to cost just under $20 million.

Consequently, the museum’s focus now turns to fund-raising.

“We’ve got some momentum because we’ve got a couple of donors who have said ‘If you are ready to go, I’m ready to go,’ so the momentum is there, we just have to keep building on it,” said Mr. Nathans. Much of that momentum will have to come over the next four months before the museum decides whether to purchase the property.

Although it is now overgrown and dilapidated, Mr. Nathans said one of the most powerful fund-raising tools available to the museum could be a tour of the property itself.

“I would love to have a couple dozen people who are thinking about writing checks to share a glass of wine and watch the way the sun sets on the property,” he said. “Wouldn’t that be cool?”