I consider buying a waterproof handheld VHF to be used as some sort of
reserve radio in case mast and antenna are lost, fixed VHF fails or
need to abandon the boat...

What about radios that use AA cells instead of rechargable battery
pack? As far as I understand, rechargable batteries need to be charged
every now and then even if the radio is not used. And alkaline AA
cells, though have lower capacity, do not decay. I plan to leave the
radio in my grab pack, and would not like to worry about charging NiCd
pack every month...

Any suggestions for a good handheld? What about Icom M-31 ? Or some
similar reasonably priced set?

Mika