hay to all. just wondering does any one no of a good app for i phone 5 for windsurfing. have the otter case for it witch is surpoast to be waterproof and all that. or would i be better of getting a propper waterproof gps.
I guess what you mean is a way of recording the GPS data output from the GPS chip built into the phone.
I looked into this a while back and from memory there were a few apps that could record some of the data, mainly the 'trackpoint' or location data.
AFAIK, there are no apps that can record the equivalent of the Sirf binary data we use to get dopper derived speed and the error correction data.
If the I-phone has a sirf3 GPS chip, it might be possible, but many other brands of GPS chip can not output this data.
Even if you could record this data, you would have a very expensive device that was at very high risk. It would also probably not have the display data that the GT-31 Genie gives you about your previous runs etc.
Better, and less financially risky, to just get a GT-31 and a Paqua bag.
Not an iPhone but I've compared the results from a Navi GT-11 with a cheap Android phone using a GPS tracker application.
The results were very comparable. Not very much variation between the two. However AFAIK no phones are considered to be accurate enough to allowed in GPS speedsailing competitions.
thank you . it will give me a idea roundabout how quick i am going and apps are cheap as ill give it ago.
Keep in mind that smashing an IPhone 5 is near $1000 replacement whereas a gps is a few hundred and a lot tougher.
Should be some old posts listed on this topic from last year , unless you need to have the real McCoy for the GPS comp the iPhone apps are fine, Acurate and give you google map prints, use the Australian sold hard iPhones case for protection and a soft arm case to carry,
The downside is that it sucks your battery dry and the bloody phone rings when your on the water, I use it for Sup also handy for photos also.
I use 'boat tracker' there maybe something better? Also have an app for mountain bike rides which also adds height and speed peak trough graphs also.
well got a otter case (armour) WATER PROOF 3 METERS DROP PROOF 3 METERS FOR IPHONE 5 . WENT FOR A HOUR LONG SAIL GPS ON AND HAD A FEW STACKS NOTHING BIG. BUT THE CASE DID NOT KEEP WATER OUT SO DONT TRY THIS AT HOME KIDS . ARRRRR WELL I TRYED 
That's sad to hear. I am paranoid, so even when using an aquapac I sometimes wrap the device in a plastic bag too.
I carry my car's remote inside an aquapac, which itself is inside an aquapac... Hmmm.. I wonder if I could use another aquapac? 
all good ill get it sorted . found out today a clipseal sandwich bag does the job. ok all u wise humans out there what is the gps unit that is used by fellow windsurfers. and can be used for comps (speed). and easy to use as for not a brain surgeon .
GT-31 is the only way to go. Would not use a sanger bag though.. unless I was taking a sandwich of course..
Aqua pac or Paqua.... best bet
