Mayor Kirk Caldwell says he’s willing to consider the idea of making improvements at the Waikiki War Memorial Natatorium that would allow the public to swim in it again, but only if a new proposal being offered pencils out financially and makes sense.

Caldwell’s new position drew applause Monday from the Friends of the Natatorium, which supports restoration. The Kaimana Beach Coalition, which wants the structure removed and returned to a sandy beach, took a cautious, “wait-and-see” stand.

The mayor, who has been inclined to choose a beach-only option, said he hopes to end a five-decade-long debate and render a final decision on the Natatorium by spring 2019. His ultimate wish is for work to begin before he is scheduled to leave office in January 2021.

The Natatorium was opened in 1927 as a tribute to those who gave their lives during World War I. Celebrities from Duke Kahanamoku to Buster Crabbe and Johnny Weissmuller swam there, as have thousands of Oahu’s youths. But it fell into disrepair and was shut down over health concerns in 1979.

Whether the facility should be restored and reopened as a pool or the bulk of it should be torn down and cleared for a public beach has since been a controversial issue, often hotly debated.

Reconstruction and restoration would cost between $40 million and $60 million, while creating a beach, which would be accompanied by a replica memorial arch, would cost between $20 million and $30 million.

But a new draft environmental impact statement describes a third alternative — creating a so-called “perimeter deck” to replace the original deck that is now crumbling. Also at a cost of a between $20 million and $30 million, the new option would retain the bleachers and arches, and reconstruct the pool deck using a new support system, allowing for the free flow of water between the swim basin and the ocean.

Caldwell said the city does not yet know how much in annual maintenance and operations costs each alternative would entail.

A fourth alternative would be to do nothing, but Caldwell said that is not an option.

Mo Radke, president of the Friends of the Natatorium, said he’s optimistic now that the administration has opened the door to averting a tear-down. Radke said no one ever wanted to rebuild a complete pool due to the costs. He noted that a beach-only option is just as expensive as the deck option because of the need to rebuild groins that protect the beach and sand.

Rick Bernstein, longtime Kaimana Beach Coalition leader, said he doesn’t know enough about the perimeter deck proposal to determine if he supports or opposes it. His group is, however, firmly against keeping the bleachers up because “they were built to view swimming races, and to maintain the bleachers for no reason other than perhaps commercialization … would create an attractive nuisance.”

After public hearings on the draft environmental impact statement in fall 2018, a final EIS is expected to be released in spring 2019.

In a news release, Caldwell called the new proposal “promising,” if it’s deemed feasible, since the two versions appear to be in the same price range according to preliminary data.

That’s somewhat of a reversal from April 2013, when Caldwell and then-Gov. Neil Abercrombie announced an $18.4 million plan to demolish the Natatorium and convert the space to a public beach. Full restoration would have cost $69.4 million, the city said.

The city then proceeded with a draft EIS on the demolition plan.

But in November 2016, the National Trust for Historic Preservation presented the city with a proposal to replace the dilapidated seawalls of the swim basin with individual chevrons that would allow water to circulate while diverting wave action against the bleachers. Robert Kroning, the city’s director of design and construction, said that plan would be considered under the draft EIS.

The perimeter deck proposal unveiled Monday also allows the water to circulate, except below new pool deck sections on new supports.

The beach alternative would require construction of a new bathhouse and replacement of offices that now house the Ocean Safety Division, both of which Caldwell said he’s willing to support.