I went to Bloodmoon Island first and picked up the second piece. Then I went to the Graveyard, met Tarquin, and got his quest. I then picked up the first piece and returned to Tarquin and turned in both pieces.
But he just says he needs a few odds and ends before returning to the ship and just walks around. I'm all done and want to sail away but Malady says Tarquin is not present on the ship and nothing I do has been able to make him get back on board the ship.
