Haha, Gibb,

You have a point, although I don't think you're being entirely fair here. No, the scene is actually shot with the actors singing as they're rowing in the whaleboats, so the lyrics must've been made up before they shot the scene. And considering that the rest of the film is quite true to the novel and the language of the time, I think they just took their best stab at creating a shanty that would sound at least plausible.

Sadly I just realized, having watched the trailer that was posted earlier in this thread, that one of these reasons I and everybody else can't hear the lyrics is the shitty sound quality. The sound quality in the trailer was way better than this... But it's just a fact of life that subtitling is not considered the important trade it should be, but rather a necessary evil that mustn't cost any money...