To confirm what other reviewers have said, a number of the tracks on this compilation are not the original single versions that would have been played on the pirate ships.
Keep On Running - Spencer Davis Group - this sounds like an alternate earlier take to the finished single as the words in verse 2 are very different!
To Sir With Love - Lulu this is not the Mickie Most produced original UK cut but a more sophisticated (US I think) later version.
The Sound Of Silence - Simon & Garfunkel is the earlier non-band-added version - which was not a hit.
Also as others have again mentioned - sometimes the sonic quality leaves a bit to be desired - in particular Phil Spector's Wall Of Sound production on River Deep, Mountain High sounding like the Wall Of Cotton Wool or Wall Of Mashed Potato instead!
Several other tracks are in their markedly inferior stereo takes or mixes, but this is often the case with Motown, Stax and Atlantic tracks on compilations.
This could have been a 4 or even 5 star comp, but to my mind the compilers have ruined the ship for a ha'pen'th of tar. And yes - why no groovy jingles between the tracks?!