The USS Thresher annual memorial service will be held at 1 p.m. Saturday at Traip Academy in Kittery. The service marks the 52nd anniversary of the disaster and is hosted by the Thresher Base chapter of United States Submarine Veterans Inc. for surviving family members of the Thresher crew. The Thresher (SSN 593) was a nuclear fast-attack submarine designed and built at Portsmouth Naval Shipyard in Kittery, and had just completed an overhaul at the yard when it sank during sea trials about 220 miles off Cape Cod on April 10, 1963. All 129 crew members died in the accident, considered to be the world’s worst submarine disaster.

D. Allan Kerr, author of “Silent Strength,” about the lost Thresher crewmen, will speak at Boothbay Harbor Memorial Library at 11:45 a.m. Friday. All proceeds from sales of the book will support the Thresher Memorial, which features a 129-foot flagpole and is located at Memorial Circle in Kittery. It was dedicated in 2013 on the 50th anniversary of the accident.

Photos of the 129 crew members lost on the USS Thresher are displayed at a past memorial service. This year’s commemoration takes place Saturday at Traip Academy in Kittery. File photo by Jill Brady/Staff Photographer

An “Honor Flight” film screening will take place at 2 p.m. Sunday at the Franco Center in Lewiston as part of the Emerge Film Festival. The documentary tells the story of the nonprofit organization that honors veterans by providing free flights to the World War II memorial in Washington, D.C. The film’s director, Daniel Hayes, and Earl Morse, co-founder of Honor Flight and a resident of Vinalhaven, will be in attendance and will answer questions following the film. Veterans and active-duty service members will receive free admission to the screening.

Veterans may request passes on the Emerge website, emergefilmfestival.org, by clicking on the link under “veterans passes” on the tickets page, by calling the Emerge coordinating team at Rinck Advertising at 755-9470 or by emailing info@emergefilmfestival.org.