Symmetrical Spinnakers

Originally posted by NickA Except in the matter of ease of use ... is anyone claiming that asymetrics are in any way "better" than symetrics?  In what way? Can an asymetric run a bit higher (and hence faster) due to the tighter luff?  Is the shape somehow more efficient?

I don't know that asymettrics necessarily have a tighter luff: its all in the design. Some sails and sailmaketrs are cut tighter than others.

The shape certainly ought to be a lot more efficient with an asymettric. The fullness in any sail has a tendency to drift back, and you really want it in the front, so if you start with a sail with the fuillness in the middle then you are already starting in a position of weakness. Thus with a well cut asymettric you have more shape in the front where you need it, and less hook in the leach for a cleaner exhaust and less backwind onto the mainsail. Caveat - there are some pretty dreadful asymettics out there, especially the earlier ones, and of course some designs preserve pretty old fashioned shapes.

Originally posted by NickA  note that big yachts always have symetric kites

No, actually. See, for example, almost the entire J-Boats family, VOR70s, IACC boats. I think you will also find VO70s are capable of sailing faster than the true wind in certain conditions.

Edited by Stefan Lloyd

the Scorpion open at Notts county is on the 7th and 8th too... buy one and be there! 

Also for the kind of tidal waters where you often want to run deep just off the beach to keep out of the current. All that gybing in and out with an asymetric, not good. Salcombe, Cowes, Burnham are the sort of places that is an important factor.

Originally posted by fizzicist Originally posted by redback Let's face it the symetrical kite does not increase the speed much unless you sail high enough that the pole has to be against the forestay.  So you might as well use an asymetric and sail a boat which is optimised for one. There speaks someone who has never seen a Javelin or 505 on a dead run in a blow.

As more evidence here's another Cherub archive pic. In this one, as you can tell from the shadow, the pole is a couple of feet off the forestay...



[Photo Farr Yacht Design]