"Yo-ho! Yo-ho!" is common - I think following Ed McCurdy. It sings better than Oh ah and lends itself to a short whoop after the first "ho" which is how I sing it. It just seemed to _want_ a short whoop there. There are a few othere minor differences, too. Art Thieme would be a good person to ask the source.

I posted what I believe is the "correct" (well, the original) version. Taken from Katie Lee who, undoubtedly, though not specifically stated, got it direct from Rogers. The song _did_ go into tradition, however.