The sail cannot be freed any further for now and is stuck at two-thirds height. Is it safe to just continue sailing like this?

A. The boat should be deliberately capsized to free the sail

B. A partially hoisted mainsail can usually be sailed with for now if it is not flogging dangerously or chafing badly, but the skipper should reduce reliance on it, consider motoring or using other sail area, and plan to sort the problem properly once conditions allow

C. It makes no difference at all and can simply be ignored for the rest of the trip

D. A partial hoist always means the boat must stop sailing completely and immediately call for assistance

A. A jam like this is always caused by the sail being the wrong size for the boat

B. This pattern means the wind has suddenly become too strong to hoist any sail at all

C. The halyard has almost certainly wrapped around something at the masthead — a spreader, the VHF aerial, the wind instrument, or twisted itself — and is now fouled, which is a common cause of a sudden jam partway up a hoist

D. This always means the mast itself is about to fail structurally

A. Wrap the halyard around a winch and crank it tight regardless of the jam

B. Cut the halyard immediately without trying anything else first

C. Pull as hard as possible with extra crew to try to force the sail the rest of the way up

D. Stop pulling immediately and ease the tension off — continuing to haul or sheet in hard risks damaging the halyard, the masthead fitting, or pulling something loose up the mast that could then fall