Nav wrote:
...A double harness line may also help you get back aboard if you go
over the edge.

This is *really* bad advice, based on old wives tales.

A harness tether should be short enough to keep you from going over the
side. The odds are high that if you go over the side in very rough
conditions, you will be badly injured and/or drown before you... or
anybody else... can do a thing to assist.

DSK