introducing travel-related imagery to align with a psychedelic journey conveyed in an LSD trip, a theme used more introspectively in "Tomorrow Never Knows", where Lennon exhorts the listener to "float downstream". Musicologist William Echard recognises the psychedelic traits of oceanic imagery, childhood and nostalgia as especially prominent in the song, thereby making "Yellow Submarine" one of the most obvious examples of UK psychedelia's preoccupation with a return to childhood. Recording Main session The Beatles began recording "Yellow Submarine" during the eighth week of the sessions for Revolver. The project was characterised by the group's increased experimentation in the studio, reflecting the division between their recording output and the music they made as live performers. The first session for the song took place at EMI Studios (now Abbey Road Studios) on 26 May 1966, but without producer George Martin, who was unwell. Author Ian MacDonald views Bob Dylan's contemporaneous hit single, "Rainy Day Women ♯12 & 35", as a possible inspiration on the Beatles. The two songs share a similar marching rhythm and a festive singalong quality. The band spent much of the afternoon and evening rehearsing the song. They recorded four takes of the rhythm track, with Starr playing drums, Lennon on acoustic guitar, McCartney on bass, and Harrison on tambourine. The performance was taped at a faster tempo than appears on the completed track, which is in the key of G major. Following a reduction mix of take 4, Starr recorded his lead vocal and he, Lennon, McCartney and Harrison sang vocals over the choruses. The vocal parts were again treated with varispeed; in this instance, they were recorded a semitone lower. Harrison's contribution is especially prominent, departing from his bandmates' to sing an f1 note on the word "submarine". The recording was given another reduction mix, reducing the four tracks to two, to allow for the inclusion of nautical and party-like sound effects. Sound effects overdubs The Beatles dedicated their 1 June session to adding the song's sound effects. For this, Martin drew on his experience as a producer of comedy records for Beyond the Fringe and members of the Goons. The band invited guests to participate, including Brian Jones of the Rolling Stones, Harrison's wife Pattie Boyd, Marianne Faithfull, Beatles road managers Mal Evans and Neil Aspinall, and Alf Bicknell, the band's driver. The studio store cupboard was sourced for items such as chains, bells, whistles, hooters,