Hi guys, i know the GPS watch thing has ben bought up a fair few times, but just need a quick answer.

I need a watch to keep track of the time when i want to go sailing between shifts at work, i never wear a watch so it will only be for sailing and thought i might as well get one with GPS just to see how far i've been and how fast, just for some fun.

I have seen a few guys talk about the Suunto Ambit 3 watch, do these watches have a speed reading setting for Knots? No one seams to ever mention it.

Also so will the Run the Sport, be pretty much the same, the run is about $50 cheaper.

Cheers..

Yes they can do knots BUT the reading gets very messed up if the watch goes under water, you'll have a max speed reading of over 500knots or something odd like that. It can be sorted out when you down load it though.
getting them set up and talking to the app can be a bit finicky but once up and going there's no problems.

cheers,

only 500 knots, that should be just enough, i bought a new fin.. lol..

I have a ambit 3 run and have downloaded a couple of windsurfing speed apps for it to compare. Never had a problem with the readings even if watch has gone under water. I find it easy to use and finds the GPS signal fast as well. Band is very sturdy and you can easily get replacement bands cheap off eBay, as well as second chargers. I find my Suunto lasts longer in GPS mode than the gw60 as well. And I use mine as an everyday watch too. In non GPS mode it lasts about 16 days between charges.
Hope this helps.

yeah that's mate, awesome.

I have the Suunto 9 - spend plenty of time underwater, never had this 500 knots happen I have it set in metric so is in KM/H even in the "Nautical" setting

You can have your own custom screen with the current time + other info that you choose

Thanks guys, i ordered the Ambit 3 Run, was only $138 because it's lime green, think it would be good for what i want to do.

A few weeks ago, I tried to see what kind of speed guys were getting on Slingshot foils, so I searched the GPS Team Challenge and ka72.com. I found several tracks where one guy had done 25 knots repeatedly, according to ka72.

Closer analysis of the downloaded tracks showed that all high speeds were artifacts; the actual top speeds seemed to be around 20 knots. Here is one example:

This artifact is from a crash (as were the others). The positional speed was briefly over 80 knots, the "speed" reported by the Suuonto watch was ~ 25 knots. The interesting thing is that the watch reported an average speed of 21 knots for a rather long time, 16 seconds. This indicates that the "speed" reported from the watch at least partly relies on filtered (smoothed) positional speeds. With crashes, swimming, and waterstarts, the GPS often looses reception and then regains it with just a few satellites, which leads to large positional and speed errors.

About every third or fourth session that I looked at had similar artifact. Typically, the 2-second top speed was overstated by 2-5 knots on ka72.com.

Note that spikes can also occur with the GW-60 and the Motion GPS. When crashing a lot while learning to foil, I had some spikes in almost every foil session. However, the GW-60 and the Motion record additional data that make identification of spikes possible, in particular the number of satellites and accuracy data. Furthermore, the higher recording rates on the "approved" units, and different data processing, means that it is quite rare to see spikes that extend long enough to affect 2 second results. Not impossible, but rare; I did not see any in more than 10 of my foil sessions that had plenty of spikes.

Bottom line is that you'll have to take the numbers the Suuonto watch gives you with a grain of salt. More often than not, they will be quite accurate. But if you see speeds that are higher than usual, look at them closely with software. They are often quite easy to spot by looking at the various graphs, but even "strict" software like GPSResults cannot automatically identify the artifacts because the watch does not supply the necessary extra data.

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boardsurfr said..
A few weeks ago, I tried to see what kind of speed guys were getting on Slingshot foils, so I searched the GPS Team Challenge and ka72.com. I found several tracks where one guy had done 25 knots repeatedly, according to ka72.

Closer analysis of the downloaded tracks showed that all high speeds were artifacts; the actual top speeds seemed to be around 20 knots. Here is one example:

This artifact is from a crash (as were the others). The positional speed was briefly over 80 knots, the "speed" reported by the Suuonto watch was ~ 25 knots. The interesting thing is that the watch reported an average speed of 21 knots for a rather long time, 16 seconds. This indicates that the "speed" reported from the watch at least partly relies on filtered (smoothed) positional speeds. With crashes, swimming, and waterstarts, the GPS often looses reception and then regains it with just a few satellites, which leads to large positional and speed errors.

About every third or fourth session that I looked at had similar artifact. Typically, the 2-second top speed was overstated by 2-5 knots on ka72.com.

Note that spikes can also occur with the GW-60 and the Motion GPS. When crashing a lot while learning to foil, I had some spikes in almost every foil session. However, the GW-60 and the Motion record additional data that make identification of spikes possible, in particular the number of satellites and accuracy data. Furthermore, the higher recording rates on the "approved" units, and different data processing, means that it is quite rare to see spikes that extend long enough to affect 2 second results. Not impossible, but rare; I did not see any in more than 10 of my foil sessions that had plenty of spikes.

Bottom line is that you'll have to take the numbers the Suuonto watch gives you with a grain of salt. More often than not, they will be quite accurate. But if you see speeds that are higher than usual, look at them closely with software. They are often quite easy to spot by looking at the various graphs, but even "strict" software like GPSResults cannot automatically identify the artifacts because the watch does not supply the necessary extra data.

Thanks for the simple explanation of why some GPS devices are approved and others are not.

If we didn't have the stupid 2sec category it wouldn't be necessary to have such accuracy and maybe able to use other devices. Should have a 500 metre category instead.

Ok, but i'm not really interest in all the nerdy stuff and posting times, just needed a watch and thought it would be cool to get rough idea how fast i'm going just for a bit of fun.

That's exactly why I got one

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P.C_simpson said..
Ok, but i'm not really interest in all the nerdy stuff and posting times, just needed a watch and thought it would be cool to get rough idea how fast i'm going just for a bit of fun.

Perfectly reasonable, even more so if you rarely crash or swim, and keep the "rough" in mind. I've seen several windsurfers who were very disappointed when they got a "record session" that turned out to be nothing but an artifact.

PC, I've had my Suunto (Aambit 3 Run) now for about 2.5 years and have worn it every sailing session since purchasing it (approx 120 sessions). The device is still going strong and has a whole heap of apps that you can use specifically for windsurfing. I have two screens that cycle through every five seconds whilst I'm sailing. One screen has my last alpha (knots), 1 hour average speed (knots) and total time moving. The second screen has my 2 sec peak (knots), total distance sailed for the session and current time. This is of course fully customisable to suit what you want.

The biggest thing to remember I guess is that it's for reference only and cannot be used to post to GPSTC with. For that I have different devices. I've had some massive "offs" with only one spike that made me laugh . Water resistance has been tops!

Good luck!

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Hroar said..
If we didn't have the stupid 2sec category it wouldn't be necessary to have such accuracy and maybe able to use other devices. Should have a 500 metre category instead.

This is just wrong. Read the examples above again carefully.