Garmin has a good idea for GPS/radio combo, but unfortinatly it isn't VHF.
But if you and your buddy has a pair of this toys you can see location of each other
The 5xx models 100% water proof, 5w, and have good battery. They even have a nice feature to query for other device position.
All rino models compartible with each other, and older models can be had for 100 bucks ...