Is this a pair, or a coincidence?

ruth and rue probably both stem from OD rewen. ruth and ruthful are both now archaic; but rueful and ruthful were once synonyms = compassionate.

OD?

OD

Old Dutch, Old Danish, or just plain peculiar.

And the cook was Dutch, and behaved as such,
For the diet he gave the crew-ew-ew
Was a number of tons of hot cross buns
Served up with a savory glue.

And is the next line "Friggin' in the riggin'", Bill?

Oh, a capital ship
For an ocean trip
Was the Walloping Window Blind
No wind that blew
Dismayed the crew,
Or troubled the Captain's mind.