If I were doing any flying in Alaska, especially over-water, I'd invest in a good anti-exposure suit. Dry (cough cough) land may not be close.

As for gear not working, all the gear in my vest is rated IPX7 so it can stand getting wet for extended periods, and it's been tested for those conditions. If you do get to shore, what then? How are you going to attract attention and get rescued? A PLB should be very high on your list of survival gear, way above the big knife and firearm.