1-D: Ship to Diobel
Ochnam, Kass and Isandros (maybe others?) board Ochnam's ship and it heads out of the harbor of Absalom. While it probably doesn't have to worry about colliding with any of the wreckage from the Flotsam Graveyard, it's better to pay the 10gp Pilot's Guide fee to wend its way through the wreckage.
One ship left just before you did, and as you pass through the safe channel, two more ships arrive. Neither of them appear to be the ship you are looking for, as they are small merchant ships.
Ochnam has to spend some time at the helm directing the ship where to go. While he can simply tell it 'sail to Diobel', it doesn't really know where Diobel is, and even if it did, it'd head for it in a straight line, which would have it running aground in short order.