1971 Overdubs
A later composite version of the song was completed by The Beach Boys under the supervision of Carl Wilson in 1971. The song was credited as being produced by The Beach Boys, though most of the production for the new instrumental sections of the song was done by Carl.
The first section featured a new lead vocal by Carl dubbed over the original 1966 backing track, as well as additional instrumentation. It's said that the band asked Brian to do the lead vocal as he would have originally, but he was unwilling to or possibly felt he was unable to perform it at this point in time.
The second section featured mainly Brian's double-tracked vocal and piano from the December 1966 demo recording, plus new vocal and instrumental overdubs by the other Beach Boys.
Despite refusing the lead vocal, the new ending of the 1971 version was entirely Brian's work. The third section combined the ending of Brian's demo with newly-recorded vocals and other additions, with the closing lead vocal sung by Al Jardine. This new ending was based on another Smile era track, "Child is the Father of the Man". It is unknown whether the song was originally to end this way or if it was improvised by Brian. An additional line to this section, "The father's life is done, and the children carry on," was written but was removed at Brian's request.
The newly-finished song was released as a single and also appeared on the 1971 album of the same name, Surf's Up. The B-side of the single was "Don't Go Near the Water".
Read more about this topic: Surf's Up (song)