One is in the crow's nest on board the ship --
How do I get to the crow's nest?
-- one is revealed when you solve the word search in the journal and then use the pins on the map in the captain's quarters --
How do I solve the wordsearch in the journal?
What am I doing with the map on the wall?
-- and the last one can be found when you sit in the dinghy at low tide.
How do I change the tide?
How do I find the dinghy number?