sloop did not exactly recall the folk anthem “If I Had a Hammer,” which, a couple of generations ago, inspired young people to become involved in the civil rights movement.
But one of the writers of the song, Pete Seeger, who died last year, would most likely have been pleased by the noise: The construction was in service of another dream he had, of a cleaner planet.
Beginning in June 1969, Mr. Seeger used the sloop, a 106-foot wooden sailing vessel that he christened Clearwater, to crusade for the cleanup of the Hudson River, which had been ravaged by raw sewage and industrial waste for decades.
The boat is both a floating classroom and a platform for raising awareness of environmental issues. This winter, workers on the Clearwater are expected to complete the last of a three-part restoration that cost nearly $2 million, the most extensive in its history.
“We are keeping his legacy alive,” said Annika Savio, 30, one of Clearwater’s two captains, referring to Mr. Seeger. “This restoration means we can continue to bring our message to people up and down the river. Without it, we wouldn’t be able to sail.”