Join Date: Feb 2000
Location: Annapolis, Md
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How does a geeenaker poole work ?
Gennakers work best on light, fast boats where you would almost never point dead downwind. On boats like that, even on a broad reach the wind would appear to be a beam reach or in lighter conditions forward of the beam. In those conditions as sail that is somewhere between a spinacker and a genoa can be an asset. These sails really become pretty inefficient when the apparent wind is aft of abeam. Genackers are a very narrow function sail. They fill the slot between broad reaching and close reaching in a very narrow wind range.
Assymetrical chutes have a broader range of use on lighter weight boats where thier boat speed relative to the windspeed means that they almost never go dead downwind.
For boats with L/D ratios over about 150 and SA/D under about 22, symetrical spinackers are a better choice with assymetrical spinackers (either a cruising chute or the modern racing assym. spinackers) as a less effective alternative. The problem with assymetrical spinackers on cruising boats is that cruising boats rarely have the kind boat speed advantage on a reach (vs a run) that makes ''tacking downwind'' compellingly better from a VMG stand point. While some assymetrics can be flown wing and wing, in general, assymetrics are not that stable in flight when used wing and wing amking them a cranky choice for downwind work. While cruising chutes are cut to be more stable in a wing and wing situation, they are generally far less effective than a symetrical or assym downwind.
So back to how a gennacker is flown. Under the racing rules, a gennacker is considered a specialized type of spinacker. As such, it has to be flown as flying sail (not hung on a fixed stay), and must be flown from a pole or sprit. The sprit allows the gennacker to be separated from the forestay making a jibe a little easier (reduced chance of a wrap). there are two popular set-ups for gennackers. the first employs a roller furling drum to retract the gennacker and the second uses a tack penant which allows a spinacker style drop.