I've been using the same GPS software as these guys. Works quite well. You can delete freak points and average out result with a click of the mouse. It is quite handy. The program is called gartrip (
www.gartrip.de) and it is free with full functionality except saving files with more than 500 track points. For that you have to register for 34 Euro's. But it is well worth it. It may be a little hard to use at first but you soon get the hang of it. And like I said you can download a full functional program for free.
To see some results of the plots used on a catamaran go to :
http://www.catsailor.com/forums/sho...;o=14&fpart=&vc=1&PHPSESSID=If desired you can also use a map as background and get really nice pics
Wouter