Make your way back to your ship, at the southeastern corner of the village.
When you reach the boat, someone will call for you. Talk to the man nearby and
he'll ask if your ship has a cannon. Tell him it doesn't, and he'll say that a
guy named Eddo has one at the island to the south. Looks like we'll have to get
our hands on one. Talk to Linebeck, and he'll take your new Sea Chart. He will
say "Blow me down", and the word "blow" will be in green. You know what this
means. He wants you to clean up the chart, so blow into the mic until all of
the dust is cleared. This reveals another crest on the map. Tell him you're
ready to set sail and you'll be off.
Linebeck will explain how to explore the Northwestern Sea. It's simple. All you
have to do is draw a course directly up to the end of the map, then it will ask
you if you want to go to the Northwestern Sea. You will then set sail there.
Before we do that, however, sail to the island to the south (not the island
farthest to the south; sail to the one in between Mercay Island and the Isle of
Ember. This is Cannon Island.