BEACON, N.Y. (AP) — A Hudson River educational sloop that was the brainchild of the late activist musician Pete Seeger and his friends is marking its 50th anniversary.

Some of the Clearwater 's founders and crew members will gather with public officials in Beacon, New York on Friday to mark the anniversary of its launch on May 17, 1969.

The Clearwater, the centerpiece of a nonprofit, was built to look like the Dutch sloops that once carried food and other supplies along the Hudson.

Seeger sang for migrant workers, college students and star-struck presidents during a lifetime of advocating for the environment and other causes.

A historic photo taken shortly before the Clearwater's launch shows him standing on the bow, strumming his banjo.

Seeger died in 2014.

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