David Crosby had been a member of the Byrds but was forced out in late 1967 due to friction with others in the band.  By early 1968, Stephen Stills was one of several musicians who began sailing with Crosby on his yacht and jamming with him.  One of the first fruits of these sessions was the apocalyptic tale "Wooden Ships", composed by Stills, Crosby, and Paul Kantner of Jefferson Airplane. 

As one of the few new bands, Crosby, Stills & Nash (Neil Young also played with them part of the time; the band was then called Crosby, Stills, Nash & Young) was a hit at the 1969 Woodstock festival, including their performance of "Wooden Ships".  There was a renowned exchange between songs, where David Crosby notes that this is just their second gig, and then Stephen Stills says:  "This is the second time we've ever played in front of people, man, we're scared s--tless."