From the F16 rules set currently in force.

Scooby,

Before I continue, I'm running around with a short fuse currently because of solving some design assignment that some retarded employee has managed to screw-up in no small way. It is taking me heaps of time and effort to get the dumb masses to understand. So if I seems short tempered then know that that is not because of you or becaus I disrespect you. It is just me.




So yes the F18 class is included, I understand. No class is copying more handicap finger pointing then that class currently.




Standard practice, not a problem.





Actually, if more people believe otherwise then I'm fully prepared to accept a slower handicap then the F18's. It will only favour us F16's and we can excuse ourself from then onward that we F16 sailors have tried to make it as fair as possible to all other sailors. Personally I know that I will get a favourable rating if it is more then 1 % slower then the F18's.





You guys are discussing this point with Wouter here. I have already analysed the curve that is related to the daggerboard handicap. I had done it over 3 years ago, same as with the luff lengths of the F16 jib.

The most optimal F16 board design ACCORDING to the SCHRS formula is :

0.14 (area) x 0.80 (length) (aspect ratio 4.57 dimensions 175 mm x 800 mm)

It results in a rating of 1.00614 = rounded to 1.01 = F18


The most low tech board (1988 desisgn) currently used is by the Taipan :

0.1595 (area) x 0.55 (length) (aspect ratio 1.89 dimensions 290 mm x 550 mm)

It results in a rating of 1.01836 = rounded to 1.02 = 1 % slower then F18 = current F16 handicap


Clearly the difference between a 18 year old daggerboard design and the most optimal is ONLY 0.01222 points or 1.2 %

I can tell your right now that that 0.14 x 0.8 board will be outperformed by both a 0.1875 x 0.75 board and a 0.16 x 0.8 board. Also the 0.14 x 0.8 board is very difficult to make to withstand the sailing loads put on it, its cord is too small and it both breaks easily and stalls easily.

In case people or wondering even a Taipan board that is being lengthned by ONLY 60 mm (just over 2 inches) is enough to give the F16's the F18 handicap.

So why don't you guys just give us the most efficient board specs you can find, we are pretty close to that performance already, even with our most low tech daggerboards. It is all just arguing about rounding off numbers downwards or upwards. Certainly not the kind of difference that earns serious consideration of F16 rule changes. There is simply not much in it.

Wouter

Wouter I agree with most of what you are saying.

We'll probably give you the most efficient plate to get the lower rating; now that there is some direction in the SCHRS group, why did you not ask for this instead of asking for the rating to be lowered without providing the facts to back this up ? It would have saved a lot of typing if we (The SCHRS group) had been sent a request by the F16 association along the lines of

"as our class rules do not measure plates in the same way as the SCHRS rule, please use the most efficient rating point for our SCHRS rating, this being 0.14 (area) x 0.80 (length) (aspect ratio 4.57 dimensions 175 mm x 800 mm)
Kind regards, etc....."

Simplest solution is to adopt the most efficent plate for SCHRS for the F16. I will propose this to the group tonight, the only problem, is are you acting on your own opinion, or with some backing of the F16 association(s) ?

The slowest rating you can get for a F16 by only playing around with the plates is 1.04 :

.

Simon,

I have, obviously, been monitoring the dialogue between you and Wouter on this matter.

Whilst it should be borne in mind that Wouter no longer holds any official post within the F16 Administration, he clearly has a lot of history with the formulation of the F16 boxrule. He has also carried out, in his own time and under his own volition, studies into Texel, SCHRS and PHRF. His knowledge in this field is not easily dismissed.

Whilst I am unable to say (without a mandate from the F16GC) that his proposal amounts to an official approach to SCHRS, I am also reluctant to say that his proposal would not be the line followed by the F16GC on behalf of the membership.

If you are having a meeting tonight then please do feel free to explore the option for F16 to be rated using the 'best board' method and if you require an 'official' proposal from the F16GC, I will endeavour to provide one to the SCHRS Committee.

John,

Thanks for this. Something official would be very useful.

We'll discuss it on an "un approved basis" for now....

Scooby,

You said one thing right, I'm not an F16 class official anymore and so all I say is to be taken as a private person and F16 class member.

I have transferred all open issues (with up to date notes) to the new board and offered them my continued support in all area's upon their request. I have not received any request from the board in the situation regarding SCHRS. And now I'm sort of butting in to get things done. However I had to wait for a while for this to become defensable.

Furthermore all the times that I did try to reach the SCHRS committee (if one exists) failed miserably. So you guys would have received such a request if you were at all contactable during 2005 and early 2006. I'm sorry.




Of course only the current F16 Governing Council can endorse this proposal, not me, I'm just speaking on personal title. Were is the F16 GC on this topic anyway ?


With respect to 0.14 x 0.8 boards. These are just imaginary boards, they will not work well on a F16. The area is to small. Guys, a good rule of thumb is that the daggerboard area is roughly 90 % to 100 % of the total upwind sail area. A rule of thumb number 2 is that aspect ratios around 4 are the most efficient when taken over all conditions.

The 0.14 by 0.8 board does not satisfy these conditions.

If anybody was to ask me then I would say that SCHRS should use the most efficient board specs that is actually used on a F16 in real life instead of a mathematical (and unrealistic) optimal point.

Currently such a board is of the Stealth F16 : 0.188 x 0.75 All other F16 boards in currently use are less efficient.

That is most fair to all.

With respect to the counterexample you are giving in your post :

A daggerboard with 1 sq. mtr. area and only 0.25 mtr depth is far out rediculous. It would have to have a daggerboard well that is 4 mtrs wide to result in that area. That is not a daggerboard, that is a skeg.

Sorry Simon that counterexample is beyond ridiculous and I won't take it seriously.

But for the remainder all due respect

Wouter

Again, guys please forgive me my moodiness as I'll be working till late tonight.

John, I think it best if I approach you on this matter so we can discuss options that the GC has.

Scooby, I'll help the GC to get an official proposal to you. And rest assured that it will be fair to all other sailors out there. I'm not going to lie. There is no point, we are not trying to win a ratings number game.

I suspect this will take this discussion of line

Wouter

It was not supposed to be taken seriously ! It was to illustrate that someone could build such a boat (that measures as a F16) and then turn up to an open Handicap meeting and (correctly) claim a rating of 1.05. It's a (IMO) missing component in the rules of the F16 (and F18) that the plate is not controlled more. As you say there is a relation between sail area and plate area (square or cube root of sail area / 100 I think, or something like that !).

Scooby,

Personally I see this glitch as a fault in the SCHRS handicap system rather then in the F16/F18/F20/A-cat class rules setup.

It should not be the responsibility of sailboat classes to correct an anomaly in a handicap system.

That is where we differ in opinion.

Wouter

So you would propose that plates are removed from the calculation of (any) handicap system as they do not effect performance ?

I think boards/no boards rule is sufficient.

After all between my very low aspect Taipan boards and the best F16 high aspect boards there is currently only 1 % rating difference.

However I do find that my boards are better in big wind then the tall skinny ones while in midrange winds I'm at a slight disadvantage. In the really light stuff we are equal again. Also because my V-ed hulls handle light winds better then the hulls with rounded keellines.

So I see it more as as trade-off between mid range winds and strong winds. Ergo neither board design has a clear advantage is ALL conditions. It will therefor average itself out over a wide spectrum of conditions. Then the KISS principle kicks in. There is too little to be gained in increased fairness against to much added complexity.





Partly, certainly in the current form. If anything then make all daggerboards the same and have a seperate hit for pivoting centreboards/skegs and then another for asymmetric hulls (no skeg). This maybe too simple but I do feel that 80 % of the differences are well handled by a simple rule as that. The remaining 20 % is measured in less then 15 seconds per hour and not worth the trouble.

We'll see all modern boats come out with daggerboard aspect ratios between 3 and 5 anyway. In the engineering literature that I have the difference between these aspect ratios is not too large at all. Beyond 5 there is hardly anything to be gained. If you do a hit calculation on aspect ratio 4 then both 3 and 5 boards are too close to 4 to be noticeably different. This is the "halve way value = close enough" trick and works suprisingly well.

Pretty much think of it this way. Roughly, the difference in lift/drag ratio when going from aspect 2 to aspect 3 is of the same magnitude as going from 3 to 5. And additionally the difference between 3 and 3.7 is the same as going from 3.7 to 5. So very quickly the gains decrease with each added point of aspect ratio.

That is what I would do. Actually that is what I have done as the F16 rules didn't consider the boards to be worth ruling upon.

Currently I'm working on some new daggerboard design for the F16's and we have decided to not go over aspect ratio 4 because there was not enough to be gained there for the extra effort required to make such a board lightweight and stiff. Additionally it means that a singlehander can pull the boards up to an optimal exposed area and still get an effective aspect ratio of 3 or higher. That was the compromise that we made. Aspect ratio of 3 is probably the minimum you want on a modern boat, below that you start loosing increasingly more performance.

I hope this helps.

Wouter

Just been re-reading this after last night and I need to pick you up on one comment that is a fair way up the thread Wouter.



Not quite true.

F16 one up rates at 0.98 currently
F16 two up rates at 1.02 currently
F18 Rates at 1.01 currently
A cat rates what the measurement cert. says it rates, as they are development classes; we currently think, under the current rules, that the fastest A classes (Flyer etc) rate at about 0.97, we are trying to get one measured.

Hi all,

just couldn't help but bring this one back up.

Just finished the Brass Monkey regatta, racing Steve and 3 other F18's. Over the line F16 "Altered" was ahead of all F18's in 3 races out of 4. With the Mosquito F16 mixing it with the F18's most races and finishing ahead of "Altered" and the F18's in one race. <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

Just goes to prove my point that the F16 IS competitive boat for boat against F18's. Not faster not slower but COMPETITIVE. <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" /> In some conditions one is faster than the other but overall they are both able to compete on a even footing I believe. <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" />

Look forward to the next chance to race boat for boat.

Regards Gary. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

Well done Gary and great to see yourself and Tim up here. Hope you can make it to Forster.

In the very light winds, the lightweight F16s and A Class had a big advantage, with the heavyweights only showing their speed when a bit of breeze cam in.

The A Class realy dominated this event with their blinding speed up wind whist still maintaining good speed down, despite the lack of kite. The As were up, trapping and away well before the F16s and the F18s did not even look close.

Great fun regatta but very disapointed with the lack of breeze. Was hoping to see the Cats in full flight against the Skiffs and settle what we already know <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" /> ........ Will have to wait now till next year.

Yes sailors from all classes scan these sites and rarely make comment. More importantly,newcomers happen across these forums and could be very mislead by false claims. This is why you sometimes get a "bite" from offended parties.
All catsailing is good but I prefer to race against similar boats (class racing). Handicap racing of any type is for the disadvantaged (in my opinion). I thought that F16 was about building a class so that similar boats could race each other. Why then the obsession with handicap ratings?

Indeed;

Any boat I was sailing, I would want the slowest, BUT FAIR rating I can get.

Because most of the time the catsailors fail to make class and have to race open class. And yes even the F18 class is know to fail class often outside of Europe. So F16 class aimed at getting the boat right in both modes. Both in F16 fleet racing (equal performance between different F16 makes) and relatively good equality with the dominant other classes like F18's and A-cats. That way we can eat the cake and have it too !

You will notice that we'll switch from either role to another quite easily. When fleet racing we concentrate on that, when open class racing we compare ourselfs to others. Neither role is subservent to another and no one is less important.

This is all the more valuable in club races where typically there is only one start and that is the open class. It is just much much much more fun to race again 2 other F16's and 6 F18's/2 A-cats then ONLY race against the 2 other F16's.

The challenge presented by the added F18's will make you a better sailor as it is always more difficult to win over 8 other boats (F18/F16) then over just 2 other F16's. And one of the goals of the F16 class was to better your sailing skills in any way or form. Open class racing is definately a valuable method to achieve this.


But I must also add that it personally gives me a lot of enjoyment to underdog the F18's while sailing a F16. And the F18 sailors at my club know that. Keeps them sharp and it keeps myself sharp.


Wouter

Yes Wouter and when you beat them, they know who the man is.

Sounds like "little brother" always trying to prove he is better than "bigger brother" to me.<img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

Tiger Mike

And what may I ask is wrong with "little brother trying to beat bigger brother"? Sounds like healthy competition to me. Isn't the whole point of "racing/competition" to try to "win", regardless of who or what is being "raced"?