I gotta agree with you macca on that point, why cant the other sailers allow you to use curved boards and in return you give up some yardstick, 1 or 2 points whatever, at least this gives the class the chance to develop further and explore other possible benefits for the future and will not encourage newer more modern classes as you will already be cutting edge, i recently raced a nacra 16square, he still had the pinhead but carried a mid pole spinaker, all i could say was WOW! he dropped 3 points off his yardstick and it went downwind real fast, i would not call that cheating, but ruls being ruls he was not allowed to use it other than club racing. anyhow i think you all are right about the wings and i thank you for the input, they will definately be detachable sorry about the engrish

Wings are best for the narrower Taipan 4.9s which were grandfathered in. These platforms are 2340mm wide, so can 16cm wings can be added to each side to add righting movement.

And if my intuitive maths are correct, there would be more righting movement on a Taipan with wings compared to a standard 2.5m Viper due to the Mast step being relatively closer to the leeward hull.

And in relation to the wing rule, is there anything to stop you in the rules having these wings extend aft of the hull (skiff style)?

No

"No" to which part?

Wings can extend behind the hull - nothing in the rules says otherwise

this would work almost..
Grandfathered boats need conform to the "grandfathered class rules".. The question would then be .. Can a Tiapan 4.9 (with wings) sail in a official T 4.9 regatta as a T4.9? If not then the boat is not grandfathered and must conform to all F16 rules... Quite simple really..

this would work in an open fleet. In an official F16 all boats start on same line first finish across wins. In an open fleet one can use yardsticks..

What you seem to be advocating is a open box rule class.. Probably bounded by length, width, max sail area and maybe weight. These were the first "International" class rules. A, B, C and D. These worked for a while and may again....

But it would upset Macca significantly and we cant have that..

True, but i could make a Viper narrower, put wings on and still meet the F16 class rules, have greater leverage and have the wings extended out the back of the boat to help "launch it" downwind.

Or, simply allow the curved boards and then you don't have ugly wings hanging off the back like an afterthought..

Sure I have the position that the class rules are too open, and encourage cheque book racing. Thats why I don't understand why the class won't allow curved boards?

Every time I bring up the rules issue I get told that you all love to freedom to build your F16 how you want, yet when I point out that there is an area of development you are restricting... the excuse is that it would be a quantum change in the boat! Well hang on a second: The A class' have yet to prove that curved boards are a quantum change so why not allow the development within the freedoms of the F16 class?

Let the A Class guys spend the money on R+D !

You get LESS RM as the mast is closer to the Pivot point; the leeward hull is the pivot point. by moving the mast towards it you are reducing the RM from the mast (and the hull).

Cats pivot on the leeward hull. To get max RM you want as much of the mass on on the windward hull (or close to it, or further away from the leeward hull).




RM can be broken down into these components (no wings)

1, Boat: 1/2 beam x mass (assuming boat is symmetrical)
2, Crew component = (beam +0.93 (average COG of a person)) x 75kg (average person weight) x no of crew on the trap + beam x 75kg x no of crew NOT trapping

Now add wings (we will calc the wing RM as a step)

1, Boat RM stays the same (but remember that because the beam is MUCH less RM drops)
2, "empty wing" rm = beam + 1/2 width of wing x mass of wing.
2, Crew component = (beam + wing beam + 0.93 (average COG of a person)) x 75kg (average person weight) x no of crew on the trap + (beam + wing beam) x 75kg x no of crew NOT trapping

Steve is correct here guys.

He's got the correct intepretation of the class rules and indeed most rules are written to be self-correcting.

Wouter

Scooby_Simon, been a while since high school physics so please excuse the cloudy brain whilst i remember, but are you considering the calc as a 2nd class or 3rd class lever? If 2nd class, then you are correct, but I always thought as 3rd class. The crew is the lead weight lump at the end of the wing/lever pushing down. The force from the sails/wind/mast is on the middle of the lever pushing up. If you can move this force point closer to the point, the more effective the force pushing down.

Am i missing something?

You been on the Moth a bit too much Taipanfc.... :-P

Decreasing beam from hull to hull despite the addition of wings will reduce your RM significantly. The pivot point for a cat is over the centerline of the leeward hull. By adding wings you through more beam (and weight) leeward of the pivot point. You are also brining the weight of the windward hull closer to the pivot point. Even reducing the beam by a little bit makes a big difference.

So, a Taipan 4.9 would be better investing thier money into a set of wider beams, tramp and stays, forgetting about wings.

If the class rules alowed a max beam and then wings, by all means go for it. If it is just max beam, increase the beam of the hulls.

Jump back on a cat mate, you know you want too :-) Sorry, could not resist.

That's the Foiling Cat I've been looking for!

Nice photoshop, now, can someone make it happen for real?

TA, happy to be proved wrong. But logic is that the beam width is made to be 2.5m for a Taipan with the addition of wings. So distance from pivot point is same for Taipan and Viper. But mast for Taipan is 1.17m v 1.25m on Viper closer to pivot. So effect is similar to a wheelbarrow but efforts are reversed. You can move more weight on a wheelbarrow the closer it is to the pivot point, that is the axle. You certainly moved a lot of dirt over the weekend so should have lots of practical experience .

Is this logic right?

I'm sorry Stephen, you post contains so many errors that I don't even know where to begin. In short, if a student would submit something like that as his final report then he would have failed the course basic mechanics.

Wouter

The weight of the luff wing will also go a long way in correcting for the less then optimal position of the mast. Yes, it weights less but its leverage is also significantly more. The intent of the rules is to allows freedom of design without leading to an unfair advantage either way.

I think this result has been pretty well achieved in this case without the use of complicated rules.

Wouter

Sorry Wouter, I sail rather than read about it. Can you fix it for me.

By the way, if I was writing a report it would be nowhere near as crude as this.

All forces balance on the leeward hull. All mass is at a distance from the pivot (leeward hull).

If you JUST have a boat; you can assume the mass (in pivot terms is spread accross the boat. The windward hull is "beam" away from the pivot; the boat is symetric and so 1/2 mass of the boat is acting at the beam. If the boat-beam is reduced (because you have wings to make it back up to the same overall beam), you have less RM from the boat (1/2 mass * beam(remember smaller + (some RM from the wing). Crew provides the same mount of RM as they are the same distance from the pivot.

IF you have wings on the boat, the mast is not in the middle of the boat (+wings) and so the mass of the mast provies less RM. Also; as the boat heels; the mast moves to the otjer side of the pivot more quickly and so reduced RM again.

Heeling moment (from the sails) is balanced at the leeward hull. The heeling moment we are "balancing" is at 90 degrees to the RM and we balance at the leeward hull.