i vote for the gps too, garmin seem to have the best range of units, maps and support. maybe an etrexH model

http://gpstracklog.typepad.com/gps_tracklog/2007/08/garmin-etrex-h-.html

worried you are trimming your gib in too much and choking off the slot, check the gps speedout reading and see what's happening

wondering where you should be when sailing a 2 crew boat solo? check the gps speed reading

bust a mast well out at sea but have your cell phone and a gps?, call in your lat/long position straight to emergency services