Pilot charts are certainly of great help for planning ocean routes and fortunately, the U.S. Defense Mapping Agency makes their Atlas of Pilot Charts available for free (get it here. you may find their server somewhat slow and rather try it here).
I’ve recently generated kml/kmz files that show the prevailing ocean winds (get more info here). Viewing them with Google Maps (as in our map at Pitufa.at) or Google Earth is really convenient. So I decided to put more information from pilot charts in kml/kmz files. For a start the gale probabilities are done. Read more »