I did some Google searching for "sailing against the wind" and found that it can be done pretty effectively by going in a zig-zag formation, but I haven't found many details other than that.
In this particular segment of the story a group of five castaways clamors aboard a schooner only to find it mysteriously abandoned. There is a violent tempest blowing it westward (against the eastward current) and they need to turn the ship around and journey eastward in spite of the wind. The tempest is supernaturally powered and doesn't show any sign of letting up. Everyone wants to hide below except for the mad sea captain. How would the sails need to be configured and how (and how often) would they need to be reconfigured to maintain a steady eastward course? How many hands would be needed on deck? Would the mad sea captain be able to man the helm on his own while the others get some rest? How quick would they be able to travel under those conditions?
I mean for them to get a little bit lost and journey too far north if that makes a difference.