we remain seabound: Rod Stewart, "Sailing", which is a def rarity if not a bustout.
ETA: it appears to be the latter. And quite lovely, so BOS5FRA. One of his tracks that was a huge UK hit and didn't do much here, iirc.
ETA2: it was a #1 UK hit in '75 and was re-released a year later and got to #3 (!). Orig recorded by the Sutherland Bros.