PORTLAND — An envisioned “immersive” experience is behind plans for a new campground in one of the city’s oldest forts.

On Wednesday, the city Historic Preservation Board had its third review of plans by Stefan Scarks and Travis Bullard on “Fortland,” a 21-site campground on and around the grounds of Fort Scammel, which sits at the southern end of House Island in Casco Bay.

Fortland would feature yurts, canvas tents and timber and canvas structures, and “has been designed to avoid and minimize impacts to the existing historical resources,” according to the application.

Scarks and Bullard said Monday they hoped the campground would be open from early May through October.

“We had a vision of an accessible site we could really share, we are finding a use to preserve and protect this amazing space,” Scarks said.

The plans will need certification as appropriate by the Historic Preservation Board since the island was designated a city historic zone in January 2015. It is not yet clear whether a site plan review by the Planning Board will also be required.

In May 2014, the island, owned by Harold Cushing and his family for almost 60 years, was sold to the late developer Michael Scarks.

“In going through the site, we immediately fell in love with such a unique space, and we took very seriously the stewardship of the resource,” Stefan Scarks said.

He grew up in a family that enjoyed camping, and said a campground is a natural fit for the fort.

“Our goal is to have it be as accessible as possible to as many groups as possible, as well,” Scarks said. “We are looking for folks wanting an immersive experience — transformative travelers.”

Fort Scammel was first built as part of the city defenses during the War of 1812. The northern half of the island, which Michael Scarks sold to Vincent and Christina Mona shortly after the sale by the Cushing family, was used to process and quarantine European immigrants during the four-decade wave of immigration that ended in the mid-1920s, when a quota system was enacted by the federal government.

Stefan Scarks’ plans for Fortland would place the tents, yurts and other camping structures on the former gun emplacements in the fort and on the granite ledge just north of the fort.

Plans also call for a 2,000-square-foot community building, a storage shed, a water pump shed, and bathrooms. Fortland will be solar powered by panels placed in the parade grounds.

Scarks and Bullard said they welcome public input on their plans at www.fortlandmaine.com, and are still working with the city on the concept. With Fortland accessible only by water, campers will land at the granite pier on the west side of the island.

“There is no berthing in the current designs, but several boats can be launched and landed simultaneously,” Scarks said.

The yurts would be year-round structures, but the canvas for tents would be removed and stored in the winter, Bullard said. Details, including site rental costs, are still being determined, but the partners expect the market to determine the cost for campers, with possible seasonal discounts as part of the pricing.

Plans for a 21-site campground at Fort Scammel on House Island in Casco Bay are under review by Portland’s Historic Preservation Board. (1971 photo courtesy City of Portland)

Campers coming to the proposed Fortland campground on House Island in Casco Bay would use a renovated granite pier. Developers said additional boat berthing is not planned. (City of Portland photo)