Hi Keef,
You only need to install drivers if you're going to update firmware. If you just want to go out and sail then you don't need to.
Just stick the card in the GT-31, format it, and go sailing! When you get home take the card out and stick it in a card reader.
Windows should read it just like a USB memory stick -- and you can then use a program to work out your speeds.
That said it is better to sort out the driver issue eventually. If you get stuck I'm sure that there are some cockies willing to lend a hand to get it all sorted out.
If you're running windows, I'd go with Mal Wright's program "realspeed". If you're running anything else, GPSarPro.
There's another thread here, about the KA72 site Dylan has set up, that will extract the numbers needed for the challenge.
Realspeed and GPSarPro have to be paid for, (but not too much), Dylan's site is free.
Should I have my Interface NMEA or BINARY? In the Memory Card section should I set the NMEA Items as ( GGA,GSA,GSV,RMC) or SBN ?
Thanks for helping.