Slab Reefing

A reefing method that reduces a sail by lowering a horizontal panel and securing new tack and clew points.

On a boomed mainsail the halyard is eased, the selected reef tack and clew are brought to their working positions and the sail is re-tensioned. The loose panel lies along the boom and may be gathered with reef points, but those points normally contain cloth rather than carry the principal sail loads.

Single-line and separate tack-and-clew systems use different leads and sequences. Cringles, hooks, blocks, boom sheaves, lines and reinforcement must take the load as designed, and reefing should be practised before heavy weather rather than improvised under maximum tension.