If you've got used to the watch initialising very quickly. You've possibly started moving around before the GT31 sorted it self out.

There's been a few issue in the past similar to yours, so when using the 31 I always make sure it's showing speed before I start sailing.

Have you looked at the .SBP file from the internal logger?
That doesn't create new files, it's all one. If you have good data on the internal logger then you have an intermittent connection to the SD card.

This has also been a problem with the 31s, if the screws in the card compartment looked corroded then the card pins could also be corroded. The pins can also loose tension over time, I think some people have had success re-tightening the pins.

So there's a few possibilities for you.
Let us know how you go

Isn't there also a size limitation with the SD cards, need to be 2GB or smaller?

Macroscien said..

decrepit said..
If you've got used to the watch initialising very quickly. You've possibly started moving around before the GT31 sorted it self out.

There's been a few issue in the past similar to yours, so when using the 31 I always make sure it's showing speed before I start sailing.

Have you looked at the .SBP file from the internal logger?
That doesn't create new files, it's all one. If you have good data on the internal logger then you have an intermittent connection to the SD card.

This has also been a problem with the 31s, if the screws in the card compartment looked corroded then the card pins could also be corroded. The pins can also loose tension over time, I think some people have had success re-tightening the pins.

So there's a few possibilities for you.
Let us know how you go

Thanks , if could be the card. I had problem reading with few USB readers , so it could be some corrosion here. Will try to get new SD Card.

Peter the gt31 will work without sd card .
Good for 150kms .if dodgy connection.
Just put your 2gb card in to download file or use your usb cable.