Some recent incidents and discussions have promted me to post this information again. This has been covered before in various threads and forums, but some sailors may not have caught this advice.

Please do not put a GPS inside your wetsuit or crash vest or enclosed it in Neoprene in any way! This is a recipe for disaster and frustration! Wet/Damp wetsuit material has been proven to block GPS radio signal reception to cause loss of satellite lock and data errors as many have found to their cost. Best practice is to wear the GPS in a waterproof plastic arm band bag on the upper arm with the GPS facing the sky. Some wear the bag on the top of the shoulders or backpack. Best is in (or on) the helmet on top of the head: http://www.mtbest.net/speed_sailing_helmet.html

It is very important not to allow the armband to slide around the arm so that it is underneath it facing the water. This will also destroy accuracy and satellite reception quality. The Australian Paqua bad is one example of an excellent arm bag: http://www.paqua.com.au/paqua_range.htm#MIDI

Do not use the 'low power' setting on your GT-31. It has been found to dramatically reduce accuracy at best because it limits the number of satellites the unit locks onto, This often results in lost data or unusable data. The battery of a normal GT-31 in good condition should last over 24 hours of use from fully charged.

If you are going for any GPS PB or record, please check your GPS settings and seek advice if you are not sure. It is always good to test everything before a big day arrives to make sure your systems work in the right way in use,

Hope this helps. Good speeds and fun to all!

Here is another big tip that could save you a lot of angst:

If you travel a long way between sessions, say, more than 50-100km's, your GPS may take some time to get a proper fix.

Its a very good idea to turn on you GPS and let it sit outside for at least 15 mins to allow it to get a good fix and aquire all the satellite location data it needs. Do this before you go out for your session.  Once you have allowed it to find it's location it will be fine until you move some distance again.

For example, when we got to Luderitz last year, we put our GPS on the balcony the first morning. It took some of them well over 15 minutes to get a good fix. If you had not done this before your session, you may find you have lost the first past of your session. Too bad if you did a PB! :-(

This happened to me at Lake George a couple of years ago. I had 3 GT-31's. Two in my helmet and one on my arm to view. I turned them on and cleared them and then put the two in the helmet. The helmet was sitting on the seat in my van until I went out. The other was on my arm getting a fix outside as I finised rigging. In this session I set what would have been a world record 1 Hour, but afterwards I found the two GPS in the helmet had missed the first 10-15 mins of the session due to not haveing got a fix yet. You can imagine my disappointment.... :-(

Thanks Andrew.

I usually have mine in a water tight box with my phone and all this inside a neoprene home made bum bag with the rest of my emergency stuff for the 'crap happens' days. Nothing like being prepared when your 4.5 Km out and enjoying the solitude! I'll give it a go on my arm and see if it gives me wings. One thing I do (as I don't trust pouches to be waterproof) is put the GPS inside a latex glove just in case. Don't think this should affect the accuracy at all and could save the unit if (when) the pouch leaks.

The problem with reception seems mainly due to the water which is trapped in the neoprene. Water blocks radio signals.

Plastic bags seem to have no effect on reception and I think Latex would be fine as well. God quailty zip lock sandwich bags work as a last line of defence.

The position of the GPS under your back would also block diract signals from the sky. Signals reflected off the water (multipath) are bad for accuracy.

Hey, sometime ago i put my very wet Wetsuit above the BGT31 while BT connection to the mobile phone running "Locus" to check Position and Sat Fix.. The Result will be 8 satelites, minimal change while laying the BGT face to face without Wetsuit above. Since then, wearing the BGT31 under my wetsuit in an Aquapac on my thorax for more than 10.000 km.

Some sessions this year i use a new Aquapac with armstarp. The result is a moisture BGT31 and an unpeasant feeling because of the strap.

Bump!