As the wind becomes stronger you may need to reduce sail area. Methods vary, as different classes use a variety of reefing systems. Make things easier by reefing ashore, at a mooring or at anchor. If none of these are viable, sail into clear water and heave to, preferably on starboard.
A slab-reefing system includes a rope fed from the boom through an eye in the leech of the sail. A second eye is situated at the luff, above the downhaul/Cunningham.