The important function of the HX870 is
DSC. If you're stuck in a life raft and see a passing ship, this is better than flares for getting their attention. A
DSC distress signal will set off alarms on the bridge of the ship, and you can then talk to them. The HX870 will do this; other SH radios will not.
You would probably never need it if you have an
EPIRB, but
distress signalling is something where you want to have backups to backups to backups if possible.
For whatever it's worth, this is what I carry:
PLBs (lanyarded in life vests)
Rocket flares (both inside the rafts and also in the grab bag)
AIS MOB beacons (in life vests)
Signal mirror
DSC handheld
VHF with a good supply of batteries vacuum packed.
Likely overkill, but when you need this stuff, you REALLY need it.
Don't keep the
radio in the grab bag; keep it in its
charging base in a grab-able location, and put it on your grab list. If you ever need it, you want the normal battery to be fully charged. The
radio only works on reduced
power with the alkaline batteries. For the same reason, the
solar charger is also a good idea, but obviously this will not
work at night. You will need a spare
charging base for this to
work.
Handheld DSC radio is useful for purposes other than distress signalling. Good thing to have in the
dinghy. Read the various threads on it in here.