prv
Well-Known Member
a VHF radio (not sure something actually exists that maintains battery etc for years in storage)
PLBs manage it
There are SOLAS handheld VHFs for ships, that have long-shelf-life single-use batteries. Some normal VHFs are available with normal rechargeable batteries for day to day use, plus a SOLAS one which is long life and guaranteed to be charged (but usable once only) which you’re meant to swap in if an emergency arises.
Pete