Gennaker
A gennaker is a downwind sail that can be described as a cross between a genoa and a spinnaker. It is asymmetric like a genoa, but not attached to the forestay over the full length of its luff (like a spinnaker). The gennaker has a larger camber than a genoa, making it optimal for generating lift at larger angles of attack, but the camber is signficantly less than that of a spinnaker.
The gennaker is a specialty sail primarily used on racing boats, bridging the performance gap between a genoa, which develops maximum driving force when the apparent wind angle is between 35 and 60 degrees, and a spinnaker, which has maximum power when the apparent wind is between 100 and 140 degrees. Due to its geometry, the sail is less prone to collapsing than a spinnaker and does not require the use of spinnaker pole. The lines between gennaker and asymmetric spinnaker are blurry; they are both high camber downwind sails, rigged similarly to a genoa. The difference is the amount of camber, which dictates the points of sail. A gennaker is optimal for a beam reach, while an asymmetric spinnaker is optimal for a broad reach or run.
| Sails, Spars and Rigging | |
|---|---|
| Sails | |
| Course | Driver | Extra | Genoa | Gennaker | Jib | Lateen | Mainsail | Spanker | Spinnaker | Staysail | Studding | Tallboy | Topgallant | Topsail | Trysail | |
| Sail Anatomy | |
| Clew | Dacron | Foot | Head | Kevlar | Leech | Luff | Tack | |
| Spars | |
| Boom | Bowsprit | Gaff | Mast | Mast (Fore) | Mast (Jigger) | Mast (Main) | Mast (Mizzen) | Masthead Truck | Spar | Spinnaker Pole | Yard | |
| Rigging Components | |
| Backstay | Block | Cleat | Cunningham | Forestay | Gooseneck | Guy | Halyard | Knot | Peak | Preventer | Rigging | Rigging (Running) | Rigging (Standing) | Rope | Sheet | Shroud | Stays | Throat | Truck
| |
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