You guys should add the MAELSTROM!
Even without the tornado inside it.
The Maelstrom could be located in the center of the map or can be created by a powerful storm around the map.
You can also add the Tornados that can destroy completely your boat if they take you. Same thing for the Maelstrom. These are places hardest to navigate, and can scare even the most brave pirate!
A spectacular action can be, when the tornados (which move around the map) go inside the maelstrom, and BOOM!!! A spectacular and deadly moment to see!

