50 SETTING AND SHEETING SAILS
50.1 Changing Sails
When headsails or spinnakers are being changed, a replacing sail may be fully set and trimmed before the replaced sail is lowered. However, only one mainsail and, except when changing, only one spinnaker shall be carried set at a time.
50.2 Spinnaker Poles; Whisker Poles
Only one spinnaker pole or whisker pole shall be used at a time except when gybing. When in use, it shall be attached to the foremost mast.
50.3 Use of Outriggers
(a) No sail shall be sheeted over or through an outrigger, except as permitted in rule 50.3(b) or 50.3(c). An outrigger is any fitting or other device so placed that it could exert outward pressure on a sheet or sail at a point from which, with the boat upright, a vertical line would fall outside the hull or deck planking. For the purpose of this rule, bulwarks, rails and rubbing strakes are not part of the hull or deck planking and the following are not outriggers: a bowsprit used to secure the tack of a working sail, a bumkin used to sheet the boom of a working sail, or a boom of a boomed headsail that requires no adjustment when tacking.
(b) Any sail may be sheeted to or led above a boom that is regularly used for a working sail and is permanently attached to the mast from which the head of the sail is set.
(c) A headsail may be sheeted or attached at its clew to a spinnaker pole or whisker pole, provided that a spinnaker is not set.
For the purposes of rules 50 and 54 and Appendix G, the difference between a headsail and a spinnaker is that the width of a headsail, measured between the midpoints of its luff and leech, is less than 75% of the length of its foot. A sail tacked down behind the foremost mast is not a headsail.