RE: How To Operate a Standard Horizon HX851 VHF Radio

The GPS function on the HX851 is useful when sending out distress signal. It is not useful as a navigation aid unless you carry charts with you on the water, and know how to read them. A couple things to keep in mind using GPS on the water:
1) Your direction of travel according to your position over ground might not be the direction your kayak is pointed. You have to take current and wind into account. So if you are paddling into strong current and wind,  your direction of travel over ground may be opposite the direction your kayak is pointed.
2) Do not follow GPS headings blindly without consulting navigation charts. This is especially important in the fog or at night where there are no visual navigation reference. There might be a reef or land between you and your destination.

To navigate on the water, I use the GPS mapping function on my fishfinder.

Definitely something to be aware of. Since I have a GPS fish finder I would use my HX851 as a backup GPS. That would involve marking waypoints along the way. Then if you need to use it to get back, you would be following a known safe route. I have not seen any topics discussing navigational hazards for specific launch or fishing areas, but I haven't looked either. Something I'll need to study up on as I gear up to do some ocean fishing this year.

You abandon yak, lose yak, sink yak', fishfinder will not help you get located.  Handheld vhf and handheld GPS attached to pfd, or a handheld radio with GPS built in.