I also knew it as "father's grave"...I remember my step-father used to sing it. I am also reminded of a Victorian-style ditty of my late father's, which concerns a family unable to pay the rent when the landlord has come round, and had threatened to burn down the privy. One of the ragged children is singing plaintively:

Please don't burn our shit-house down
Mother has promised to pay
Father's away on the ocean blue
And sis in the family way
Brother dear has gonorrhoea
And times is fuckin' hard
So please don't burn our shit-house down
Or we'll have to shit in the yard.

I once sang this at a Bucknell Morris Ale, for Mick Jones who was at one time the pipe and tabor player for Wheatley Morris...he was absolutely speechless with mirth..!!!