After you talk to Elisabet, walk up the stairs to her left and look for a sign that says "Crow's Nest" with an arrow to the left.
Hint 2
Climb up and up and UP the ropes as far as you can go -- and this is the crow's nest. Thank goodness this is a computer game; in real life I would have had to stop halfway up to throw up.
Hint 3
There's nothing to do here except look around, until you read the journal in the desk in the captain's quarters.
