In preparation for the planned start of water taxi service on June 10, the group planning the Thames River Heritage Park on Tuesday announced the formation of the Thames River Heritage Foundation to support the park and offered charter memberships for $200 each.

The nonprofit foundation is being created to take the park planning to the next phase, overseeing the development of the multi-site attraction and the water taxi service that will connect it, said Penny Parsekian, head of the Communications Committee for the park transition team. The park will be made up of 19 existing historic sites on the New London and Groton sides of the Thames River, anchored by Fort Griswold and Fort Trumbull state parks, the Submarine Force Museum and the proposed National Coast Guard Museum.

The transition team has been working to organize the park since July, taking over where an earlier planning group left off.

The announcement Tuesday was sent to about 350 park “stakeholders” — people who have expressed interest in the park through its website, www.thamesriverheritagepark.org/, responded to surveys and signed up at meetings. In a letter to the stakeholders, Chris Cox, chairman of the transition team, said charter members will get unlimited rides on the water taxi for the 2016 season, and would be invited to an end-of-season cocktail party. In addition, discounts on admission to the seven historical sites that charge entrance fees may be available.

“Your membership will help provide needed support for the new park and the water taxi service,” Cox said in a letter to park stakeholders. “We are limiting the number of charter memberships to 100, so jump lively and join us in this effort make our region a destination and our rich heritage more accessible for all to enjoy.”

Operators Jacalyn and David Dietrich of Voluntown have been selected to operate the water taxi service, which will run on weekends this summer. Two surplus Navy vessels are being readied for use as water taxis.

j.benson@theday.com