[jjjtronics]

Charlie, I mounted my AM/FM/CD inside the CC, behind the dash, and it gets wet, ?????, plus all the humidity that condenses inside the cabin, the radio lasted only a couple of months. I will mount a new one later, but not inside the CC. I have water leaks from the screws/holes which support the long black rubber guard that runs around the boat.

Look at the picture to see how I installed my VHF, and believe me, this corners behind the windshield, are the two dryest places on my V20, is like majic, stuff does NOT get wet here, dont ask me why, and I do get rough seas when sailing to Culebra Island.

I made an extension "table" for the VHF using 1/4" starboard, and that way managed to sit all three gadgets in the dash top. As far as the wet-compass, really do not know how acurate it is because I pay little attention to it, but it matches the GPS fairly OK when naving, I see errors, but only a couple of degrees.
I asked myself the same question, but when I mount the gear ( I keep it in the house when not in use ) I see no movement on the Card, I can assure you of that. The VHF mount is aluminum Icom OEM, and the mounting screws are all SS of course.
By the way, the wood "table" in the instrument panel is a cover plate for the holes that the black panel had, I mounted the Voltmeter and Fuel Gauge somewhere else. The table serves well for the Cell, Glasses, Binoculars, food, etc.

JT