Hi guys,
I just set up the GT-31 for the first time. I think I got it set-up reasonably well.
I'm not sure how everyone uses it though.
That is, you are ready to sail, power it on, then what?
As the Speed Genie screen settles, it appears to start a new trip starts automatically, but has the previous trip closed, saved, or just continued?
What happens when you select "Save to Card". The rip is saved then re-set? Or just a portion saved?
What's the general process everyone does before/after the sail?
Hi Obelix, glad to see you are using the GPS again. Hopefully we might see you posting scores?
After turning on the unit I go into trip meter and zero everything, then into speed, save to card and then zero everything, especially history. That way the numbers you see are the numbers for your current trip, not previous ones.
I think "save to card" does just that and then starts a new file, so only save to card at the beginning or end of your session.
If its set up correctly it will save to card when you switch it off. To zero everything go into the last menu and select delete-all. All the speeds are zeroed, the only thing left is the total distance under the trip menu, which I leave just out of interest for battery life. Trip distance should be zero after delete all.
You may need a firmware update for this delete option, in the older firmware its not there, also the new firmware avoids any freezes more often.
Cheers guys,
Go to 'Misc' , go 'Delete' then delete all (this clears all the 'Speed' readings) next function is 'Trip meter' do the same to clear the trip meter readings.
No need to do them individually.
Reading instructions does help...
Just successfully upgraded the firmware, and now the last menu has many more options.
I presume the "Trip auto save" would be upon turning off redsurfbus mentioned above, and now Toby's comment "turn it on, turn it off and check in at home" makes sense.
Max/NS Max - 
NS Max Avg -
Now for some wind...
Thanks guys 
Those Max/Ns Max are for speed genie
You can decide which speeds to display when you reach your set speed genie speed.
Ns is N being the number of seconds which we set to 10.
So Ns Max avg is your 10 sec max avg
As Lao shi said, those options are for the screens that rotate when speed genie turns on. You can set it to turn on at your choice of speed (27knotd for me so it beeps while I try to beat my nmi max).
Default has loads of screens it scrolls through, I have most turned off, I just want to know current run max/10secs and pb max/10secs for when I drop in to look either after what feels like my best ever run (rarely is) or after half an hour or so......the fastest feeling runs are usually not the fastest!
One more thing I have got into the habit of is doing the delete all while the memory card is out and in the computer at home, then you don't end up with loads of tiny files on the card from at home...it also means I don't have to faff before going on the water
Thanks, guys.
I think I'll leave them all for now, and reduce after I've been using it for a while.
But if this weather pattern of windy weekdays, and windless wekends persists, I may be forced to swap my gear for some fishing rods. 
There seems to be some confusion about the "save to card" option.
This is only an emergency function!
If you are sailing with an SD card installed, all the data is automatically stored on the card as you sail, in the .sbn format. This data contains everything, details about number of satellites in view, and other useful stuff for analysing accuracy of the data.
Every time you switch on and off a new file is created, so there is no need to separate sessions.
If there is a problem and you find the card empty, the "saving to card" saves the internal data logger to the memory card as an .sbp file, this data is compressed to fit the much smaller internal memory, it doesn't contain as much diagnostic info. And it's all one file, as new data comes in old data is deleted to make room, I think there's about enough for 7hrs.
Be warned if you post this to ka72 all 7hrs are visible, as some of our members have found to their embarrassment.
And you have to figure out how to separate the sessions.
I strongly recommend not saving to card, unless you have a problem with the .sbn file.
