HARTFORD — As commandant of the U.S. Coast Guard, Adm. Robert J. Papp Jr. has made it a priority to develop a national museum dedicated to the maritime service. After years of discussion, developers have committed to a location in New London, but as Papp prepares to retire next month, the project still has a long way to go to raise enough money for construction to begin on the $80 million museum.A ceremonial groundbreaking is planned for May 2 so that Papp can be recognized, and hoist a shovel, while he is still leading the Coast Guard. Papp has pledged to remain involved after he leaves the service.“I’ll even sweep the floors and take the tickets if I have to,” he said in an interview. “We’re going to get this thing built.”The commandant, Gov. Dannel P. Malloy and New London Mayor Daryl Finizio signed an agreement in February pledging support for the museum, a four-story, 54,000-square-foot building proposed for the New London waterfront. The U.S. Coast Guard Academy, also in New London, has a museum, but backers say the new project will be the first national museum to honor the service’s 224-year history.Papp, a Norwich, Conn., native, had followed the fledgling efforts to develop a museum for more than a decade when he became commandant in 2010 and put the support of his office behind the idea of building it in New London.“I hope when they come in there what they see is first and foremost a monument to the rather large part the Coast Guard has played in our history, and I hope they get a sense of the uniquely American organization that the Coast Guard is that has been imitated by countries around the world,” Papp said.First, developers have major fundraising to do.The effort that began in June has raised nearly $300,000, said John Johnson, treasurer of the National Coast Guard Museum Association. He hopes the museum can open by early 2018, but it needs tens of millions more dollars.“I’m not the least bit daunted by it,” Johnson said. He said he has been targeting individual donors but is now focusing on corporate sponsors.The association hopes the federal government will contribute as much as $30 million, but the law that authorized the museum more than a decade ago prohibited the use of federal money for its design and construction. U.S. Rep. Joe Courtney, who represents eastern Connecticut, said that treats the Coast Guard project differently from national museums for other service branches, and he has had discussions with House colleagues to pursue federal funding opportunities.Courtney also said he has 276 of the 290 co-sponsors he needs for legislation that would require the U.S. Mint to create a commemorative coin that honors the Coast Guard, with proceeds benefiting the museum.The state of Connecticut has pledged up to $20 million for a pedestrian bridge and transportation upgrades around the museum.