NORTH HAVEN — Each summer, the North Haven Casino is a hive of activity. Despite the name, nobody gambles or watches over-the-top performances at the Casino.

Instead, it’s the hub base for small sailboats that swoop through the Thorofare, piloted by excited junior sailors and overseen by teen instructors. Experienced sailors compete against each other in weekly races. Just off the water, experienced and novice tennis players alike smack balls at lessons and club matches.

The Casino buildings, shingled gray structures bridging North Haven’s Main Street and the Thorofare, have had a varied history. Levin Campbell, president of the Casino’s board of directors, said they used to be fish houses, owned by the MacDonald family.

“After the collapse of the sardine industry in the 1880s, the house and wharf were bought by early summer residents,” he said. The complex was named the Casino not for games of chance, but in the context of a social club or country house.

The North Haven Casino was incorporated in 1912, said Campbell. The North Haven Yacht Club was organized earlier but never incorporated.

“One reason they bought the pier was that the only access to the water was to drag your boat over the mud flats,” Campbell said. Yacht club members paid rent to the Casino, but eventually the two organizations merged.

The Casino celebrated its centennial in the summer of 2012. For Commodore Jens Eckstein, the Casino offers a place to connect with family, visitors and residents of other islands or other places on North Haven.

“For us as a family, it’s the starting point for a sail or a cruise to a beach, and the returning point after a day in Maine’s water and sunshine,” he said.

Vice-Commodore Josie Iselin, a Vinalhaven resident, said she sees the Casino as a crucial connector to North Haven.

“The Casino is a town square of sorts, a place where the skills needed to be in boats, to sail, to peruse our body of water that is the Thorofare get taught and passed down from generation to generation,” she said. Iselin learned to sail at the Casino, as did her children, who are now sailing instructors themselves.

“The Casino is the way in and the way out to and from this life on the water for many,” she said.

Unusually, the Casino has been a hive of activity all winter, as Prock Marine has gone to some unusual measures to replace the pier.

“The impetus was the pier was in bad shape,” said Campbell. A worker from Prock discovered the issue when he was asked to look at a beam under the Casino in winter 2012. “We engaged an engineering firm in Camden to do some assessment and the basic recommendation was the pier be replaced,” Campbell said.

Steve Durrell, Prock’s project manager on the job, inspected the pier in January 2012. “A lot of the piling and timbers were in need of replacement,” he said.

Prock built a temporary steel structure in order to slide the main building off the pilings, and also slid a shed onto an old part of the pier. The pilings were demolished section by section, Campbell said.

Although granite was considered to replace the rotting untreated oak pilings, which were installed in the 1970s, it was decided to work on the same footprint, said Campbell.

“The new structure has fewer pilings, slightly bigger beams,” he said, “so the structure is engineered from the ground up rather than grafting onto something that was done 50 years ago.”

Campbell said the structure went from 130 to 50 pilings.

Island residents watched with interest as the buildings were moved. Prock first attempted to move the buildings using a crane, but slid them into place instead.

“We’ve been very impressed with how quiet the job has been compared to other wharf projects that we’ve been around,” said David Hopkins, who operates the Hopkins Wharf Gallery next to the Casino. He also lives near the Casino much of the year.

Durrell said weather “and the fact that the job is located on an island,” posed the biggest challenges. “You can’t just run to the local hardware store,” he said.

The crew mostly stayed on the island during the week, Durrell said.

Work was completed Jan. 23.