A good pirate knows where they can moor their ship safely to stock up on provisions and new cannon balls!
On this map there are lots of lines going up and down and side to side, these are called grid lines. Each of these grid lines has a number so you can tell which line you are talking about.
If you want to talk about a particular square on the map you can use these grid lines to help you.
For example if you look at the map of ports below - Port G is in the found in a square.
The way you would describe the square is 18,69
Notice how I wrote down the side to side grid line number first, then the up and down grid line number.
Always write the across number first
Write the up number second
One more example: Port L is in square 14,66
Now you are ready for Captain Blackbeard's challenge