Crazy Ideas!

That is rubbish peter! Assymetric spinnikers are designed to be sailed with on a windward/leward course

http://www.hydesails.com/information/racingspinaker.pdf the polars show what I mean

Originally posted by TheSeaFalcon ...what is the performance difference between a symetrical spinnaker and an asymetric??!

Its a somewhat vexed question... You need to differentiate between the spinnaker itself and the way its set. Intrinisically you want a sail to be asymettric as far as the flow is concerned - you wouldn't want your mainsail to have even fullness for and aft. So a symmettrical kite is at something of a disadvantage because the fullness will always tend to be too near to the leech no matter what you do with it. So you can just about always get a better shape with an asymmetric sail.

A Pole kite has a lot for flexibility about sailing deep because you can bring the pole round. Even those boats which have swivelling poles have nothing like the angle. However gybing an asymmettric kite on a pole is a nightmare. They had such sails in Cherubs in the 50s and early 60s, and you had to have two sets of sheets, one to use as the guy and one as the sheet, String frenzy! Also you can gybe a symmettric kite witthout it collapsing.

Originally posted by Peter Rhodes an asymetric gives less speed on very deep courses...

This is more to do with how its set - with a pole kite you can pull the spinnaker right round to windward which is fine for slow boats on dead runs where there is no flow across the sails so its just about projected area, Like this the main isn't blanketing the kite. Also by bringing the pole round you change the slot between the main and jib.

Originally posted by stuarthop ...Assymetric spinnikers are designed to be sailed with on a windward/leward course

Well, most modern asymmettric equipped boats are designed to be sailed on a windward leeward by virtue of having such a huge spinnaker that it would be little use for anything else! If you gave say a Mirror or a Scorpion an asymmetric kite on a fixed sprit the same size as their conventional one it would be an utter disaster! Of course the easier handling of a bowsprit kite means that you can cope with a larger kite than a pole kite boat.

Originally posted by andy_cherub & Assymetric kites are MUCH faster...

Gybing downwind was invented long before modern asymettric kites Andy, there were quite a few Cherub sailors who did apparent wind sailing with pole kites. When we started experimenting with asymmettrics in the Cherub I got a special apparent wind symettric kite made, and in spite of being smaller there wasn't a great deal of difference in speed. Losing three places on every gybe soon put an end to the experiment though! One of the pioneers of gybing downwind was Russ Bowler, now part owner of Farr Yacvht Design and the first Cherub World Champion. He built a 12 foot skiff that was such a complete cow on a run that you just couldn't sail it dead downwind, so he had to apparent wind sail!



Edited by JimC

if you look at the polars on the hyde sails link you will see that a symetrical kite goes faster downwind and an asymetric is better for reaching, so for a conventional triangular course it will be quicker and running will be quiker because you can go in a straight line fast and above all you have a choice of how deep to go with pritty even performance so can use tactical positioning to better effect

Don't Assymetric boats use windward leeward courses when class racing because it opens up a whole lot more tactical options on the high and fast/low and slow front? On a small lake when handicap racing, the ability of a conventional kite to run dead down wind puts it at a huge advantage over normally faster asymmetrics. Given a reaching course where the asymmetric can make the marks without gybing, they say goodbye to the conventional boats and disappear into the distance. Makes running handicap races very difficult, as the result is predictable from before the start between bowsprit and non bowsprit, and we don't have enough of the latter out regularly to have a separate start, which we tried for a couple of years.