KITTERY — About 300 people gathered to remember the crew of the USS Thresher, which disappeared 47 years ago in the worst submarine accident ever in terms of loss of life.

The families of the 129 men who perished gathered at Traip Academy in Kittery on Saturday afternoon. Foster’s Daily Democrat says shipyard Commander Bryant Fuller was among those who addressed the crowd.

Faulty piping was blamed for causing the Thresher to sink below crush depth while it was conducting a test trial off the coast of Cape Cod. The bodies of the crew were never recovered.

At the time, the nuclear-powered, fast-attack sub, which was built at Portsmouth Naval Shipyard, was the most advanced in the world.