Large stock of Alkaline batteries for your handhelds, and a couple sets of rechargeables and a solar charger
That said, you will be less vulnerable to nav errors if you have a GPS
chart plotter, and the charts
for it will be a lot less expensive than the minimum set of paper charts, but you will want at least large scale paper charts (and a way to keep them dry) for the trip.
maker; either a minimalist hand pumped version (desperado conditions) or some other, with the accompanying electrical
complexities. You will need a gallon per day per crew just to stay alive. Jerry cans would crowd you off the boat, and a watermaker
can mean less weight.
You definitely want an AIS receiver and a DSC vhf radio
, to hail those big dark lumps in the night. AIS will give your their name and MMSI number, and a DSC
radio will hail them regardless of their frequency choices.