How can I make the ship go off-course?

Hint 1 of 11:

The bosun steers the ship. The nest boy watches the horizon through the
telescope.

Hint 2 of 11:

You must confuse these two.

Hint 3 of 11:

The nest boy sleeps like a log.

Hint 4 of 11:

Put the Kalimari postcard on the telecope! The postcard is in Long Johns'
cabin, in the diary. You will get it after looking at the diary.

Hint 5 of 11:

Have you asked the bosun about the art-of-state pirate navigation?