After the Merchant Ships sail, the Navy Ship sails up to a certain amount toward the active player, stopping on their Map Card. It must always sail toward the active player’s Pirate Ship (even if they are Hiding Out in a Cove). The Navy Ship is not affected by Storms.
The amount the Navy Ship can sail is based on the number of Treasures the active player has buried:
0 Treasures: 2
1 Treasure: 3
2 Treasures; 4
3 Treasures: 5