Forums > Windsurfing   Gps and Speed talk

GT-31 alternative - more accurate but..

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Created by boardsurfr > 9 months ago, 3 Sep 2013
berowne
NSW, 232 posts
7 Nov 2013 8:34AM
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It is hard to please all people all the time...

For me I'd like the following features;
Waterproof without a pouch
Wrist sized
Clear display
Race start timer
24 hour battery

Optional extras
Memory card is optional as long as it has sufficient internal capacity
Bluetooth
Audio feedback - seems popular but I can never hear my GT31!
Vibe feedback

Most of the time we know the best tack for a speed run, so mast mount above the boom, or on it, could also be good..

Also my GT31 froze twice recently so I could be in the market soon!!!!

sailquik
VIC, 4175 posts
7 Nov 2013 5:55PM
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Select to expand quote
decrepit said..

I'm not sure the mast is a good place, especially for alphas. If you're doing laydowns, that 10hz track is going to have a spiral in it.



Yep. The mast is a BAD place to attach your GPS for a number of reasons. Some:-

- When you spin out and crash the mast gets SLAMMED into the water. It can smash anything!
- The shock loadings and shaking on the mast play havoc on accuracy with aliasing.
- As mentioned in gybes, especially during Alphas, the mast movement will add accuracy problems.
- It can severely disrupt the airflow over the sail and lead to loss of performance.

Its not that easy to see it in that position anyhow.

By far the best place to mount your GPS is on your head/helmet where it gets Bio-Dampening and great all round reception. (thats how I do it - www.mtbest.net/speed_sailing_helmet.html )

Next best is on your upper arm which is often the most practical for most people.

sailquik
VIC, 4175 posts
7 Nov 2013 6:02PM
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Select to expand quote
berowne said..

........Also my GT31 froze twice recently so I could be in the market soon!!!!


There are a number of well documented reason why this sometimes happens. The best solution is to make sure you GPS has plenty of time to get a good fix and download all the Almanac data it neds before you use it, especially if you have traveled any moderate distance since last use. At Luderitz we set up our GPS's on the Hotel balcony for half and hour the day before we sailed. Then we had not issues. others who did not do this had units freeze.

Some firmware versions are more prone to this freezing. If yours does it more than once, think about updating the firmware to V1.4



Dylan72
QLD, 550 posts
11 Nov 2013 5:35PM
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Select to expand quote
mathew said..

(...snip a bunch of stuff...)

Never used a gopro?


No, I've never used a gopro. But I don't get your analogy anyway. Would you prefer to use iPhone video than a goPro? What is better, to use a device designed for the purpose, or to use a 99c app on a $500 general purpose device?



NotWal
QLD, 6684 posts
15 Nov 2013 6:32PM
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Can we have accurate altitude? Not the it matters for sailing but I'm guessing that for skydiving accurate altitude is required so maybe BlowFly FlySight has it.

As far as audio jacks are concerned is it not feasible to use blue tooth headphones? That's another device I know with it's own set of problems but it could be optional and no jack is required. (I think. I don't really know)

ian0703
VIC, 5 posts
22 Dec 2013 5:56PM
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Just been reading about the Pebble watch in relation to yachting navigation and thought it might be useful to this discussion. This is the Pebble watch article www.panbo.com/archives/2013/12/seanav_app_now_with_ar_gofree_and_pebble.html

It seems to be open source, have reasonable battery life, has Bluetooth connectivity and has vibrate alerts. You could then have the gps datalogger base unit sealed and installed on your helmet and if you want live readout then connect the Pebble watch via Bluetooth.

Not sure if it would suffer the same drowning issues that others have raised with sports watches though.

DaGodfather
SA, 280 posts
12 Feb 2014 1:54PM
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So what is the current status of this (or any other) GT31 replacement?
I haven't seen any posts discussing it since the above - have I missed something?
If a new person wants to start speed sailing right now - what GPS would they need to buy? Are new GT31s still available or just second hand ones?


mineral1
WA, 4452 posts
12 Feb 2014 12:19PM
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Select to expand quote
DaGodfather said..

So what is the current status of this (or any other) GT31 replacement?
I haven't seen any posts discussing it since the above - have I missed something?
If a new person wants to start speed sailing right now - what GPS would they need to buy? Are new GT31s still available or just second hand ones?




New are getting light on. Only one outlet in WA had any a week or so back. Yes it is a concern, decission time for the guru's in the system I think.

powersloshin
NSW, 950 posts
12 Feb 2014 5:59PM
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Select to expand quote


Ha, ha, pity it stops at 30 knots !

SeaSkip
VIC, 97 posts
12 Feb 2014 6:02PM
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You would have used it a week or so back, G, but not now

Boombuster
QLD, 487 posts
25 Mar 2014 2:24PM
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So I hear the shop are running out of GT-31s again is there a substitute watch stye yet.

Wineman
NSW, 1361 posts
26 Mar 2014 11:03AM
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Reading on the weekend about Aust hi tech firm, Catapult Sports, that makes the devices worn by footballers, basketballers etc.

Should we (as a consumer user group) be approaching them to develop a device with GT-31 functionality

Just in the GPS Team Challenge alone there are 1300 registered sailors (total international)
Most of whom use a GT-31 or similar

And it is 10Hz

Select to expand quote
sailquik said..
1. A gps chip capable of outputting raw binary data including Doppler speed dilution of precision which we need for the accuracy calculations. Preferably at 10hz.


From the Fin Review on the weekend:
www.afr.com/p/technology/billionaire_mark_cuban_invests_in_G6DVPn7RKpUCrXgnJZbdHI

Outdoor GPS Sports device
www.catapultsports.com/system/outdoor/
Product: OPTIMEYE B5

The most advanced GPS device for boat sports.

* Market-leading GPS device for rowing, canoeing and kayaking
* Fourth generation 10Hz sports-specific GPS for precise positional data
* Optional ANT connectivity for connection with peripheral devices
* Integrated inertial sensors with 100Hz accelerometers
* Powerful 2gb internal computer for sophisticated processing
* Wireless reporting with no cables or downloading required
* Distinct streamlined design with water resistant exterior

Interesting, no?

DavMen
NSW, 1454 posts
26 Mar 2014 11:59AM
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They have a great name too - very apt for our sport.

Wineman
NSW, 1361 posts
26 Mar 2014 3:04PM
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Select to expand quote
DavMen said..
They have a great name too - very apt for our sport.



Good one, Dave

Maybe we can get the other Dave aka 'Katapult' to negotiate

mr love
VIC, 1655 posts
26 Mar 2014 3:38PM
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Na , can't use KAtapult, thats the new KA speed sail range specifically designed for sailing in water that is a bit too shallow for your fin.

Would be very interested in an alternative device. Had the GT31 Deep freeze again the other day after loading the firmare back on for the second time. It appears the mistake I made was not going to watch "the Hobbit" before I went for a sail after switching it on.

Man0verBoard
WA, 629 posts
27 Mar 2014 10:55AM
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Have been talking with Catapult - Sailquik I have pm'd you.

Cheers
Adam

sailquik
VIC, 4175 posts
28 Mar 2014 5:30PM
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Good lead. Cheers guys!

SurfSailAUST
WA, 19 posts
Site Sponsor
5 Apr 2014 2:37PM
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Surf Sail Australia still have good stocks of the GT31. We also have more on order from Locosys, they are still producing it seems.



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Forums > Windsurfing   Gps and Speed talk


"GT-31 alternative - more accurate but.." started by boardsurfr