Just had a look at their website.
The Ambit watch has an accelerometer filtered GPS which is an interesting idea but it doesn't give details as to the data recording frequency or type.
The Sirf IV chip is good enough but if it is like Garmin's latest watch it may only log data at variable intervals. (edit:can be set to 1 sec intervals)

So to try and answer your question. Will it give you a speed? Yes. Will that speed be accurate with the faster change of speed of windsurfing over running? Not clear from the info they provide.

The GT31 records doppler data which allows it to be much more accurate for our purposes than most GPS units.
Very detailed review here www.dcrainmaker.com/2012/04/suunto-ambit-in-depth-review.html

lao shi said...

Just had a look at their website.
The Ambit watch has an accelerometer filtered GPS which is an interesting idea but it doesn't give details as to the data recording frequency or type.
The Sirf IV chip is good enough but if it is like Garmin's latest watch it may only log data at variable intervals. (edit:can be set to 1 sec intervals)

So to try and answer your question. Will it give you a speed? Yes. Will that speed be accurate with the faster change of speed of windsurfing over running? Not clear from the info they provide.

The GT31 records doppler data which allows it to be much more accurate for our purposes than most GPS units.
Very detailed review here www.dcrainmaker.com/2012/04/suunto-ambit-in-depth-review.html

Also looks like its more than twice the price of a GT-31

Wish the GT-31 was waterproof though

Yeah they are pretty expensive. Cool though. I see they have adjustable settings, one for running and one for cycling. If it can track you on your bike, it shouldn't have much trouble following you on the water. I'd like to be able to see if you can plot it on Google maps though.