Sailor Steve is bang-on. I started a similar trip back in 2008 and stopped shortly after reaching the Galapagos Islands.
Part of the reason was because I was informed the game wouldn't allow me to cross the International Date Line but the main reason was a dinosaur ate most of my crew...
The first part of my thread (from Ubi forum) is here but the back end of it seems to be missing:
http://forums.ubi.com/showthread.php...ype-VII-Forums