Great! Now all we need is the tune...

"And the mermaids there wept over me" is a better line I think. I think it'd be good to have the last chorus end with :

Down at the bottom of the sea
And the mermaids there wept over me.

(Imagining that last chorus as being the sailor lad's farewell.)

That's how the folk process works, variations creepm,in, and sometimes they are better than what was there before.