Its hard to imagine!
The south end of the island has very few trees left.
The green ones are what you want to choose for the water. Chop open the top (stem end) with four cuts from your machete(you do have a machete don't you?)point the stem end to the ground(so you don't loose a finger) and wack at an angle four-3 inch chips off the nuts base at the cardinal points.
You can also use the bare-hand method. Take your bare hand, reach into your pocket, pull out a 20 dollar bill and give it to a local to open some for you.