The GPSMAP 276C has two serial ports, one for connecting to a depth sounder
and one for connecting to a PC. The manual doesn't list depth data as part
of NMEA output. I've learnt that waypoints can include depth data. I'd like
to know if track points can list depth data together with positions and time
stamps.

Also' I'd appreciate ideas on how to obtain a data stream to a logging
device such as a Palm pda containing NMEA messages for position, time and
depth - even if the depth data has to be brought in separately from the GPS.

Another way to do it might be to use a Garmin iQue 3600 (which I have) and
direct depth data to it over serial connection and have an application save
data to the SD card. BTW, there will soon be an application available
allowing for serial output of NMEA GPS data from the iQue.

The aim is to gather data for a local chart of the sea bed. Any info on the
topic would be most welcome.

Regards

Jonas Lonnroth
Brussels