Hi Andreas,
Thanks for suggestions.
I am wondering how did Garmin eTrex perform in this application? Is it good enough?
I will try to contact Tom, hopefully he is not employee in Locosys. 
Sincerely,
Geoffrey
Hi Geoffrey,
The etrex works but is not great for speed reading as speed fluctuates a bit as not using doppler. Also not convenient to have dangling from your neck which actually disturbs the speed readings in low speed as not fixed in space, a watch formfactor would be much more convenient. Very good to have sea charts in the etrex though which is great for sailing.
If you do develop a firmware for sailing and windsurfing, you should definitely include a sailing countdown timer. Not sure if you have this already but features should include:
1. Easy to set countdown with starting periods with minutes increments up to 60 minutes.
2. Easy to reset countdown (i.e. press a button once countdown has started and countdown goes to closest full minute (i.e. goes to 3.00 if you press the button both at 2.55 or at 3.05), essential to be able to reset countdown if you miss the first start signal by a few seconds).
3. Beeps at each second the last 10 seconds of each minute the last 5 minutes with stronger beep at full minute. (beep, beep, beep, beep, beep, beep, beep, beep, beep, BEEP). BEEP at each minute for 10 to 5 minutes before start.
4. Once countdown reaches zero, normal stop watch should automatically start taking time so you can time the race.
Regards,
Andreas