Hello ****

>>Do not ever use my name again on any of your posts.


Okay, ****, I will not use your name anymore.

>>I do not think your intent is honorable and I do not want to be a part of it.

Think what ever you think and then try to stay true to the facts. One more note. if you think the anomymous attacks on you, like the one one the old forum are coming from me then I can garantee you that I will always sign my name to a post. Rest assured there is no comspiracy to "get a ****", these are all people who just want the truth to be told. Differences of opinion ? No problem. False claims ? You will get heat. And beleive me when I say that another other party will get that treatment under similar circumstances. Hell even I received some heat in the past, and often rightly so, when I stepped out of line.



>>Your comment about me and "only one solution" is your invention. I have never said that.

It is true you have never said, but you hint at in in all your other comments. They always go along the lines. "I already knew back in the 70's that .... and still boats today have .... . Of course all ARC and SC product do have .... ever since the first was produced as the only class / product .... etc"


>>>About pitchpole and H14s and 16s: I did my design work on the SC product line in the mid 1970s. At that time the H14 and H16 were the largest and fastest growing classes in the US. They were the chinning bar at that time and their sailing characteristics were the ones to improve on.


Perfectly understandable and that was never the thing I railed against. Point was and still is. That eliptical hulls have since then been replaced be rectangle hull with heavily rounded decks and after that inverted triangular shaped hull where the pointy side is towards the sky. The designed have moved on. I can assure you that an elliptical hulled A-cat or F18 will not be a big hit on today's cirquits. And there is alot of effort and rep going into these designs currently.


>>>Inter 20 vs Tornado: Why do you think the position you bring forward exists?

Simply because the I-20 can get away with a fat flat deck because of teh rounded corners (as you also say) and because the excess volume keeps the bows up. No matter how you put it I-20 hull are not ellipical in shape and do have very good dive resistance. It was an example of a different solution.


>>Elliptical hulls: When the best and finest F40 one design boat was designed it looked like a scaled up SC20.

When was the last F40 designed ? And I know that making a good small airplane goes along different line than a good major jetliner. Large differences in overall size do often alter design problems enough to warrant different solution or tip the balance into a different direction. All the big cats (club med etc) have a 3rd beam in front of the mainbeam. It will be clear enough that this is not a particular smart thing to do on beach cats that are shorter 20 ft.


>>On the big cats and tris the elliptical hull shapes are the industry standard. Even there we see alot of fine entry bows that transform into a high rectangle with rounded corner tehn transition into an ellips or rounded box section and then end in rounded triangular or semicircular sterns. In one hull we go from a flat tall rectangle to a triangle or semicicle via box, rounded rectangle or ellips midsections. We do we want to call these elliptical when they incorporate almost all sections know to man and different station along the date line ?


>>>Shared Lift: I first used the shared lift idea on the SC17. Half the lift to counter the side force from the sail was carried by the forward sections of the hull, deep Vee shape, and the other half carried by an oversize rudder.

There is simply no catamaran that doesn't use shared lift in this sense. With each design part of the resisting sideforce is provided by the hull, sometimes a part is provided by daggers as well and the residue is taking up by the rudder.


>>This performance improvement shows that the shared lift concept works. The SC17 also tacks much easier and faster than the H16 and is much much more pitchpole resistant.


So, all boats designed after 1980 tack better than a Hobie 16 ? And almost none use the same setup as your 17 footer. Big win.


>>>Shared lift and spinnakers: The European beach cats are slow to come to S Florida so I haven't sailed any of them.

Okay , that is fully exceptable and will never cause me to post sceptical comments. Honestly.

But of course even with this fact, "I haven't sailed any of them", you tend to give alot of advice regarding the right construction of these systems to inquiring posters. A favorite claim of you was and is that spinnakers introduce alot of leehelm on cats. Clearly you can't know that when you haven't sailed any of the post 1994 spinnakers; by your own admission. If you don't know then don't comment on it with such displayed certainty.



>>>But looking at pictures of them sailing with spinnakers, I see a big difference from the spinnakers I sail with.

By inquiring posters always ask advice regarding THESE NEW STYLE EUROPEAN SPINNAKERS. I actually think they more Australian in origin but that is a side issue. The gennakers were first developped on the large Aussie skiffs and then jump ship to the F18 class and F20 classes. So you sail with different spinnakers, fine, I have no problem with that. However all modern cat sailors, I-17, I-20 , F18, F18HT, Tornado's, F16's, any new aftermarket spi for any sailor upgrading his cat out of the range H20 to Prindle 15 is getting the new cut spinnakers. Clearly it stands to reason that your experience with old style spis (who did really behave differently) is not really helpful in these situations.


>>>I look at pictures of these European cats sailing double trap and I notice the leech of these spinnaker sails is just in front of the mast. These are very high aspect ratio spinnakers.


They are indeed, and the speeds they are operated in are also alot higher. Most modern spi boats currently sail with an apparent wind at about 80 degrees from the centreline or even less. They are very far apart from true spinnakers; hence the name gennakers.



>>The spinnakers I am use to are fairlead to the rear beam or transom. When sailing hot, the leech is only a couple of feet in front of the rear beam fairlead point. Now let's go back to the text book and aerodynamic theory. I see that the short footed, high aspect ratio spinnaker has a much higher lift to drag ratio than the long footed, full size, low aspect ratio spinnaker. This means that the resultant force from the high aspect ratio spinnaker will cross the platform, the boat, at a point, very near the CB trunks, that has little to no effect on helm. The full size spinnaker with its lower lift to drag ratio will generate a resultant force that crosses the boat in front of the CB trunks and this causes lee helm.


And I think you say a true thing here, it seems to explain what real life sailing shows us. See I have no problem agreeing or honouring your plausible statements when I see them.


>>>The high aspect ratio smaller spinnaker will sail higher and faster than the low aspect ratio when sailing high in general. The larger low aspect ratio spinnaker will sail faster and deeper than the smaller high aspect ratio spinnaker when sailing low in general.


Definately true. The breakthrough in both skiffs and cats was that propulsion using lift and apparent wind allows these crafts to move around the very physical limit of max speed of a mormal spi as this sail try to sail itself in a windless hole it has created itself. Of course this is the very reason we don't see these true spinnakers on high performance sailboats anymore. Actually teh skiff designers found that increases in downwind speed currently have to be sought in reducing the operating angle of attack of the whole rig. Something that was totally weird some 15 years ago. The new line of designs are approaching minimum angle of attack limits. Meaning the luff of the sails start flapping before the craft has reached its top speed on a given course. This is the main reason why the spis are being cut flatter and flatter.


>>So, there you have it, Wouter. If you sail with these short footed, high aspect ratio spinnakers, you can live with the helm with the CB located in the classical position. If you go with a full size spinnaker, the boat requires the CB trunk to be located further forward to balance the helm.

And you are fully correct in this. And as we cat sailors do now exclusively sail with "these short footed, high aspect ratio spinnakers" there is not any reall leehelm problem that needs solving by a daggerboard well in front of the meainbeam. Of course such a setup may have other convincing advantages by that is another discussion.


>>Take a look at Alinghi. This boat has a second daggerboard half way between the main beam and the bow to trim the boat out when large headsails are used.


I think these boards have a different function as well and that that is part of the reason why they are so far forward.


>>I'm tired of writing. Goodby Wouter,


Goodbye ****

Wouter