thanks for your message and great to hear you’re enjoying the game so far. To find the submarine you have to wait 5 minutes after your talk with the Sultan aboard his ship. Then if you return to the dock outside cnocsville and talk to the girl there, she will tell you where to go.
the lady upstairs in the tavern in calafort should accept your Midgeridoo. I’m not sure what the error is. I Will have a check but that didn’t come up in play testing.