New London — When organizers of the National Coast Guard Museum first publically rolled out preliminary architectural designs in late 2016, they emphasized it was likely that the designs would change dramatically. The latest iteration of the designs is proof of that.

Museum organizers are not unveiling the new designs publically, because the board of the National Coast Guard Museum Association has not approved them yet, but allowed The Day to view them Friday afternoon at their new office adjacent to Crocker's Boatyard. The museum association will present the designs at a later date, and will also solicit public comment on them.

The changes were made to address feedback from government agencies such as Federal Emergency Management and the State Historic Preservation Office, and public comment solicited as part of an environmental review required before construction on the museum can start. Museum officials also reviewed online comments on stories about the museum on The Day's website, according to Wes Pulver, a retired Coast Guard captain and executive director of the museum association.

The proposed site of the estimated $100 million museum is adjacent to Union Station on one-third of an acre of land that the city donated to the Coast Guard in 2014. An updated cost estimate for the project isn't expected for at least a couple of months. The project tentatively is scheduled to break ground in 2021, but that is subject to change.

The first architectural designs unveiled in December 2016 envisioned a four-story building perched high on the New London waterfront with a glass facade facing the Thames River. The Boston-based architecture firm Payette, which came up with the initial schematics, is also behind the latest designs.

The new designs show a much more opaque structure on the waterfront side, with long metal panels breaking up the glass. The Connecticut Ornithological Association worried about birds flying into the glass. The Coast Guard was concerned with keeping the glass clean, and the cost to do that. And those in charge of the interior exhibits said that with light reflecting off the glass, it would be difficult to see and use the interactive exhibits that are expected to be a part of the museum.

The new plans envision a five-story building, still between 70,000 and 80,000 square feet and around the same height, that will include the main floor, three floors of gallery space, and an event space on the top floor. Pulver, the executive director of the museum association, said a lot of work this past year has gone into developing programming. He mentioned the possibility of hosting leadership development training at the museum after hours, and said the intention is to use the building as much as possible even when the museum is closed.

The entrance of the museum, originally proposed to face the waterfront, is now on the side of the building, toward City Pier Plaza. That side of the building will be glass, and hanging from the ceiling inside, in view from City Pier Plaza, will be a Coast Guard rescue helicopter, possibility with a mannequin of a rescue swimmer hanging from it. Dick Grahn, president and CEO of the museum association, said that would provide an "iconic" image that would make the building immediately recognizable as a Coast Guard building.

Charles Klee, the architect, said by shifting the entrance, he hoped it would draw more people to come to the museum from State Street or the waterfront, so that visitors are not all coming via the pedestrian bridge that will provide access to the museum and the waterfront, including Cross Sound Ferry. The new designs shift the position of the pedestrian bridge slightly north on Water Street. The bridge eventually will span Water Street and the Amtrak railway line and connect the city-owned parking garage with the train station platform. Last month, the State Bond Commission approved $19.5 million to continue work on the bridge.

The proposed site of the museum is in a 100-year flood zone. That complicated the design process, and museum officials have spent a lot of time working through environmental concerns and regulations with FEMA, the state Department of Energy and Environmental Protection, the Army Corps of Engineers, Amtrak, and local, state and federal officials.

Total fundraising for the $100 million museum stands at about $36 million, including $11 million in private donations and $5 million from the federal government. The rest of the money is what the state committed for the pedestrian bridge.

The museum association recently moved its office from the back of 239 Bank St. to 78 Howard St. Grahn, the CEO, said the group outgrew its previous space now that it has 10 full-time staffers. The museum association started renting on Howard Street on May 1.