The floating verse "If I'd a-known my cap'n was blind I'd a-stayed in bed till half-past nine" is found in alot of the prison work songs (Can't think of any shanties that would refere to the captain in this way).

"I believe I'll roll on down the line

It takes a number 1 driver down the line"

Don't know if this on is close, you could try another version "Plumb the Line". Anyway hope this might help a bit. Barry