How big should a jib sail be relative to the mainsail?

Answer 1

One a sloop, it depends on what you're doing. On racing boats in light air I've seen jibs up to 180%. That's a heck of a lot of sail to tack if you're soloing, and it's not super useful most of the time so you'd best be rich too, and have a Lot of bags. As a general purpose sail (i.e. if I were to have only one jib), I'd go from 90% if I sailed solo a lot in medium to heavy air up to 120% if I was in an area that was customarily light air (Laguna BEach, Calif, for instance).