For decent USB to Serial
port connections the old pfranc dongles are no more. Got an email
from Larry that they quit selling them (they do still sell Garmin cables). Seems they don't support 64 bits. The new ones to watch for are based on the Prolific chip. That would include the new Belkins and others. They do have 64 bit drivers and claim a higher transfer rate that clearly is well beyond NMEA
. Lots of really crappy serial
port USB devices are out there but you can still get a great one for under $20.
While I loath RS232C serial ports
, if you need an interface you still need it.
I just picked up a cheap
Garmin GPS V on ebay for $60. You can disable all the vehicle navigation
features and reconfigure for the water
pretty well. The In vehicle features by todays standards suck but it makes a nice GPS for uploading way points and routes. I used to like the Garmin 128 but the prices are so high now they are not worth the $100 they seem to be selling for. Even West Marine
has eTrex handhelds for under $100 (just).