Originally Posted by HUMBER P4VWL
Just a thought. Though there are many ways to skin a cat.
Indeed, and here is another:
One battery, and a bit of suitable length rope with a knot one end & a toggle the other.
Electronics wise there's a handheld VHF under the seat, which gets discharged & recharged the nights before I go out, and a Garmin 12 full of a heap of "tactical" waypoints which sits on the console being powered off the boat battery (gives a "get you home" trail), but has a heap of AAs inside which will give it a further 12 hrs should the boat battery die. Nav. lighs taken care of in the instance of the main engine failing (no charge) by switching from ">7knts" to "<7 knots" mode, i.e one 10W lamp, which at some point I plan to replace with an LED bulb. What's left of the main batt should keep that alive long enough to get to a place of safety. If not, I have a battery ARW that can be gaffa'ed to the frame.
Or, in summary, anything vital hanging off the boat battery has a low power, aux or fully manual backup.
And I have had to use the manaul start option when my main batt switch decided not to play after a particularly bad soaking.......