You look over and see a sailor and you cuss at him while sneaking up the gangplank. On this gangplank you can be seen by everyone and are vulnerable to attack from sailors. You should move out of this group, leave it empty and move onto Ship 1 as fast as you can. All 9 Pirate ships are hidden. You must be invited to board each one and join that pirate gang to see the group. Go to the forum in this group to learn how.