This is an unfair question! As a singlehander most of the time I rely most on the autopilot hands down. But a close second is the windlass
and followed by the chartplotter.
Unless you have a very ballanced boat you are forced to streer and that really limits everything else.. including navigation
and plotting your course.
Shiva has chain and anchoring
without a windlass and chain is pretty tough. I could do rope rode
, but that is still pretty hard ... especially in a blow when no one is at the helm
motoring slowly forward. So the windlass is #2.
With the autopilot one can trim, cook, use the head
and plot your course etc. The plotter is a pretty quick way to get the big picture. For nightime the radar becomes essential so it is #4 and mine shows on the plotter (MFD). That's my my line up for single
handed do dads. I love em!
head sail is there too, but this seems to be almost universal except for racers. Don't consider this single
, but doing sail changes solo is a "process".. I prefer to leace to the furling