Help choosing "MARINE" GPS_hand_held with upload map C_Map/others from Laptop?

Hello
I travel for sport fishing, by 4WD towing a boat, along the 2000 kms coast
line.

I need a hand_held_MARINE_GPS which will allow me to upload the local map
to
my GPS.

The maps to upload could be MARINE C-Map or similar like Navman or
Magellan
CD maps.

As I fish in very remote areas I may need to enlarge or modify these MARINE
maps using a laptop computer.

Most GPS are battery hungry. This is not so much a problem because I have
enough 12 volts battery.

I need to see electronic charts with coastline detail;
navigation aids such as lighthouses, buoys and channel markers;
spot soundings and depths contours;
TIDES would be a real bonus.

Guy
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