New York developer Durst Organization has ordered the closure of the Philadelphia Marine Center marina just north of the Ben Franklin Bridge in an early step toward developing the surrounding piers, sending boaters scrambling for new places to dock vessels that, to some, are a full-time home.

Adam Rosenberg, Durst’s director of residential properties, said in a letter sent to marina users Thursday that the facility — acquired as part a 5.3-acre assemblage of four piers it bought in March 2017 for $21.4 million — would close permanently April 15.

The marina needs to be cleared so divers can start surveying the area’s underwater terrain for reports needed by the Army Corp. of Engineers for its permitting processes, which are aimed at protecting sensitive marine life and can take several years to complete, Durst spokesman Anthony Campisi said.

“We are announcing this closure now because we want to give you enough time to find new accommodations for your vessels and will work with you to help facilitate this process," Rosenberg wrote to the marina’s users.

Michael Nuzzo, who has been living with his wife at the marina on their 40-foot Silverton Yachts vessel, said he was caught off-guard by the announcement and doesn’t know where he might be able to move his floating home.

“They should have let us know this six months ago. It’s not like they just come up with it,” said Nuzzo, 50, who estimated that as many 20 boats at the facility serve as full-time residences. “I have no idea where I’m going now.”

About 55 vessels are currently docked at the slip, but all 150 of its slips are generally occupied during summers, Campisi said.

Boaters are barred by their leases from living in their vessels, but the prohibition has long been ignored by the marina’s management, Nuzzo said.

Jerry Ehrlich, who docks his 26-foot Uniflite sport-fishing boat at the Marine Center just a few minutes’ walk from his home in the Waterfront Square condominium building, said the immediate area has few alternative marinas. Space is tight at the small Pier 3 and 5 facilities south of the Ben Franklin Bridge and at Penn’s Landing, he said.

The Marine Center also offers the only fueling dock and full-scale waste-tank pump-out facility in central Philadelphia, with the next closest marinas offering such services up toward the Northeast at the Wissinoming Yacht Club or downriver near Philadelphia International Airport in Essington.

“I am really so disgusted right now,” Ehrlich said. “This is a way of life they’re going to take away from people. I don’t even know where to go.”

The marina previously was owned by Philadelphia developer Brandywine Realty Trust, which sold Pier 12 — the Marine Center pier — to Durst in a package that also included the Pier 24 parking lot north of Callowhill Street and the current sites of the Dave & Buster’s, Morgan’s Pier, and Hibachi Japanese Steakhouse restaurants.

Rosenberg also said in his letter to marina users that the Pier 24 lot was closing temporarily starting Thursday for inspections but that spots would be available for boaters through April 15 at Dave & Buster’s parking facility.

Durst, which counts a stake in New York’s One World Trade Center office tower among its holdings, has released few details about its plans for the Delaware River waterfront property other than to say it would involve apartments.

It is also under agreement with the Delaware River Waterfront Corp. to buy a 1.6-acre, publicly owned parking lot between Vine and Callowhill Streets, across Christopher Columbus Boulevard from the marina.

“As part of the revitalization of the Delaware River waterfront, [Durst] purchased several waterfront piers next to the Marine Center and are in the process of acquiring the Vine Street parking lot,” Rosenberg wrote. “In the coming months, more details about this new development will be available.”

Campisi declined to predict whether the new development would include a marina to replace the one that is to close next month. He also would not say whether Durst hoped to enlarge parts the existing piers to allow for bigger building footprints or if building may occur on platforms over waterbound sections of the its property.

“I don’t want to speculate on what’s going to happen to the remaining piers on the site. We need to evaluate their condition,” he said. “The exploratory work that we’re doing is going to help inform that.”

Ehrlich said he thinks Durst’s divers could have done their surveys around docked vessels.

“They just don’t want to put up with the boaters anymore,” he said.