The skipjack Nathan of Dorchester will offer free sails on Sunday, September 27, at the Dorchester Showcase celebration inCambridge. The sails will take place at 12:30, 1:30, 2:30 and 3:30 p.m.

The free sails were made possible through a donation from the Nathan Foundation to the nonprofit Dorchester Skipjack Committee, whose volunteers operate and maintain the vessel. The Nathan Foundation provided much of the funding for the construction of the Nathan when she was built in Cambridge in 1994.

Continuing support from the Foundation allows the skipjack to offer the free sails and act as a sailing ambassador for DorchesterCounty and the City of Cambridge as she travels the Chesapeake Bay.

No reservations will be accepted for the Dorchester Showcase sails. Passengers may sign up on a first-come, first-served basis at the Nathan booth on High Street the day of the event.

The Nathan’s regular season of public sails continues through October 31, with two-hour public sails each Saturday except October 10, when she will travel to Solomons Island to participate in Patuxent River Appreciation Days at the Calvert Marine Museum. Sunday one-hour sails will be offered on September 20 and October 18 and 25.

For more information, to charter the boat or to volunteer, contact the Dorchester Skipjack Committee at 410-228-7141 or visit its website, www.skipjack-nathan.org.