Speed over water

Hi all,

With the prevalent use of GPS systems I was wondering if anyone had ever seen the need for a speed over water measurement?

This would provide the speed of the boat in the water, and would take into account currents etc.

Cheers.

www.nkhome.com/rowing-paddling/speed-coach-gold/

Barch,

I have an old SpeedMate knotmeter that I still use occasionally. A GPS measures your speed over ground and the knotmeter measures speed through the water. These are very different things and both have their uses.

The knotmeter is very good for working on stroke technique and fine-tuning because you see the results of a change on the display immediately -- good or bad. I find such feedback very useful. The sampling and averaging on a GPS tends to make "cause and effect" stroke tuning much less effective and the GPS tends to lag behind -- although the GPS is more accurate over the long-haul.

A knotmeter might make some of the kayak reviews in magazines a bit more realistic with people posting unrealistic cruising speeds with their GPS. I sometimes wonder if they are getting a boost from a current. For example, if you are sitting in a favorable 8kt current and not paddling, a knotmeter reads 0 kts, a GPS reads 8kts. I prefer the GPS for detecting the presence of current.

I use a Garmin 310XT most of the time due to its impressive range of training features and versatility.

Greg Stamer

Stew, Greg,

Thanks for the replies. I figured there was a mechanical flow measurement system of some kind, thanks for link Stew.

Greg I agree that there certainly seems to be some utility in knowing actual speed (velocity) in water, was just wondering if a nifty device to do this would be interesting for the general paddler; to the extent that GPS are used...Have my doubts, might be a bit too 'specialist'. Had some thoughts about making such a device.

Cheers,
Simon