Pete Melvin Wins the A-CLass Worlds

Hi all,

can't wait to see a reggatta report. It's hard to know what went on with just results. Rick didn't mention that Melvin didn't win one race, the Aussies one all but one. Also Ashby finished only one point behind after drops, if all 9 races that where planned had been sailed who knows?

Before you call me on behalf of OZ a bad loser.I wold say anyway you can beat Ashby on a A class would do me. Melville sailed one hell of a consistent regatta while Aussies didn't. Just love to find out why.

Regards Gary

www.sailinganarchy.com has some more details directly from Pete.

Gary,
The report was not written by Rick. He posted a press release (and photos) that we received from Pete Melvin.

This A-Class Worlds saw no less than 8 former world champions and must be considered to be one of the strongest fleets ever. All 100 possibly entries were occupied and some 10 sailors were not allowed to enter.
Every one with name and fame was present and that means also a lot of boate builders and sail makers. See the attached results.
Conditions were indeed very calm during the worlds and it was very hot too.

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Are those "lifting foils" on Ashby?
It looks like the centerboard is angled inboard.

Yeah? So?

The A Class rules forbid hydrofoils.
At some angle, inward canting boards function more as lifting foils, than daggerboards (see Hydoptere)
There was a long discussion in March on the A Class forum about foils.
The question wasn't decided.

nor, I believe, was it decided exactly what constitutes a "hydrofoil" as the rule is worded.

Does anybody know at what parameters angled daggerboards become effective? I suppose it's dependent on weight, sail area, wind/water conditions etc?

As Pete is using them on hos own design, there probably is a rationale behind it (can't all be to throw the competition off), and I would like to know more.

I didn't think the A2 had angled boards ... at least I didn't notice it on the prototype in CA earlier this year.

Sorry Jake, you are right!
I was refering to the picture earlier in the thread, thinking it was Pete, but it's not. When I look harder at it, it looks more like Glenn Ashby?

This makes my question even more puzzling, as some A's have canted boards while others dont. I would think that it's not a big deal then?

It can be a big deal. The idea behind the canted board is that it helps provide lift on the leeward hull resulting in less wetted surface area. There was an F18 a couple of years ago that had boards that were seriously canted (something like 30 or 45 degrees!). Canted hulls are not allowed in F18 and the rules were later modified to require the daggerboards to also be in the same vertical plane as the hulls. Orma60 Trimarans and the C-class catamarans have taken the canted board concept to the extreme with the 'bananna boards' that are circular in shape - the concept works. Next time you look at an Orma 60 trimaran, consider the tiny size of the amas and ask yourself how they could possibly fly two hulls on that tiny little ama. The canted (bananna in this case) board provides the lift to give the ama extra height in the water to be able to carry the load. Somewhere I read that the optimum lifting board angle points it's lifting force at the center of lift provided by the sail plan.

With regards to the A cats, their rules prohibit the use of "hydrofoils". However, the term "hydrofoil" is not defined very well but is assumed to infer something with a t-foil shape (like the Moth or Windrider Rave has). There are those that feel that a canted board, because it provides lift, falls within the definition of "hydrofoil". It's a big grey area and it looks like Ashby was willing to test it.

I had the opportunity to study two ORMA-60's in Stockholm in May, they are very large and impressive when you float by on your small 20 footer! It was only light wind unfortunately, so I did not get to se the foils in action. I have drooled over the videos tough, and find Cheekee Monkees attempt to reproduce it on a smaller scale very interesting.
Ref: http://www.cheekeemonkee.com/

A digression: A friend,who tried hard to get an olympic berth in the 49'er class stated that he did not have any belief in those "multihull thingies" and did not care to try racing on Tornados. He is now a regular crew on the norwegian 60' tri competing in the "Oops Cup", guess he has eaten those words several times by now. "whOops"
http://www.oopscup.com/
Or for an exclusive report of another event in Stockholm:
http://www.flerskrog.org

I am still confused regarding parameters to make the angeled daggers on A's work, and perhaps they also are? But why would Glenn (if it is Glenn on the picture above) bring something untried, or less than optimal to the worlds? Is this just an uncharted area that needs more research and time?

yeah that's Gashby. Quiet a few sailors have been using these boards in the As for a few years now including Scotty Anderson. They believe it helps..... Particularly in a bit more breeze. It definatly is not slower.

(Straight) Canted boards are a compromise, the more you cant, the more upward lift you may likely produce, but the less sideways resistance you produce. Thats why the Orma and C Class went to curved boards, you get both with less compromise.

If you want to talk about an interesting way to generate lift, lets talk gybing boards. Or boards that can be adjusted in all planes while sailing or to the conditions.

Bill

F18 always used to allow canted hulls; if they don't now that there must have been a recent amendment that I missed. I don't think such a change to the rules was made though. Canted daggerboards is another matter, these are forbidden in the F18 rules if the baords are under an angle relative to the centreplan of the hulls. In effect your boards must have the same canting as your hulls.

However most F18's have gone back to uncanted boards as there doesn't seem to be much advantage to having canted hulls.

Wouter

Rumour over here (we have a guy at our club that experiments alot with these things) is that slightly inward angled boards reduce the pitching up the boat. The boat sails calmer in chop and such and this will lead to preformance gain. The lift of the boards seem to be way to small matter in a significant way through reducing wetted surface.

But like I said it is just a rumour at this time. He also says that he sail 5 to 10 degrees higher with them but I didn't see that happen.

Wouter

You're right with regard to the canted hulls - there is nothing that says they're not allowed. However, the rule was changed with regard to the daggerboards specifying that they must remain in the vertical plane of the hulls.

EDIT: sorry - I should have mentioned that this is from the F18 rule set.

The amount of angle on an A-Class daggerboard is only limited to the maximum platform width that must include the boards fitted in their pockets with the tip flush with underside of the hull. Due the slender hulls, there is not much more room than about 5 degrees angle.
As a matter of fact the boards of AHPC newest boats were made by Peter Saarberg and were within 1 mm from the maximum platform width upon measurement. Luckily a piece of the top part on the outside on both boards broke off by accident to keep it well within the class legal width limit, such a lenghth those boards are now.
In the boat area one could see that the tendence for dagger boards is defitely longer and narrower with a 1:10 w/l ratio.

So the conclusion on canted boards is that they dont seem to work on small cats, but they dont hurt you either? Sounds quite vague to me..
It seems to me that the trend for canted boards have died out, as the latest models come with 'regular' boards?

Hello all,

The canted centerboards is a better way to stabilize the boat upwind. I am sailing on a a-class which i made 2,7mtr width and it works. Because the boat is more flat upwind, so the flow along the sail is more attached to the sail in chop conditions. This means that i can sail higher upwind. For example: 1 race we had force 4-5 bft and i was sailing 4 to 5 degrees higher (alone) than F18 and F20. So i think it will work out.

Regards,

Hans Klok [color]

Any A class is capable of out pointing an F18 or an F20 (with advantage -VMG) by more than a "few" degrees simply by its hull shape, rig configuration, weight (or lack there of) etc, etc, regardless of the centre boards being canted or otherwise? So a comparison to these other classes cannot really be taken as any sort of “conclusive” result?
The only comparison would be A class to A class, - one with and one without (canted boards).
Hydrofoils by the way are of an asymmetrical profile generating lift only in one direction, due to their shape and their movement through the water, the centre/dagger boards referred to as “cantered or not cantered” are of a symmetrical profile that will generate lift on either side of the foil, depending on their angle of attack relative to their direction through the water.

This is a common mistake. If this was correct, airplanes with asymetrical section wings wouldn't be able to fly upside down - and they can. The appendage being symetrical or asymetrical is not the real issue.

What your statement neglected is the angle of attack. Given enough angle of attack, a canted symetrical daggerboard may lift a boat out of the water (although not as efficiently as an asymetrical daggerboard) - so it behaves like a hydrofoil.

Conversely, a non-canted asymetrical foil generates only lateral lift to both sides (although not as efficiently as a symetrical foil) - so it is not a hydrofoil. It does not provide vertical lift until the boat heels.

Conclusion: the rules need a better definition of "hydrofoil". But a proper definition is quite a challenge because with a bow up atitude, a "plain vanila" vertical symetric daggerboard will provide vertical lift as the boat heels. And the hulls as well, even without heeling!

How do the A class rules define "hydrofoil"?

Hey Luiz, what you have said is actually the same as I wrote? but with added examples. I never said that hydrofoils would not generate lift on either side under the (extreme) conditions you give, such as aircraft wings which, when the plane is inverted the angle of attack of the foil is increased to such a degree that lift can be generated on their “flatter” side more than the lift on the curved surface and in so doing the aircraft can remain flying etc, but there is a great penalty in drag incurred to do so. Symmetrical foils, as I said generate lift on either side of the foil depending on their angle of attack to their inclination to the direction they are travelling through the water.
Rudders are symmetrical foils and obviously generate lift on one side as well as the other whenever their angle of attack to their direction through the water is altered, and therefore, they then turn the craft in the desired direction.
What I was offering, principally, is the well established, defined fundamental, difference between the main functions of a hydrofoil and a (symmetrical) foil, (which is not considered to be a hydrofoil even though a symmetrical foil, as I said, can be used to generate lift equally in two desired directions)
When a hydrofoil is used on water borne craft, the foil is generally in a fixed attitude to the longitudinal length of the boat and the, profile shape lift that it generates is always “upwards” at (or about) 90 degrees to the waterline of that boat. This is due solely from the asymmetrical shape of that foil
This is the same for most aircraft, and in the instance you give of a plane, the tailplane elevators and the Aerolone on the wings alter the “angle of attack” to the wind direction passing over both the wing and the tail plane. In the case of the asymmetrical shape of the wing, the Aerolone will actually go a long way to altering the “shape” of its exposed “profile” to the wind, of that wing, from that of a fully asymmetrical shape when flying “right side up” to more of a symmetrical shape, to the wind direction when the plane is inverted, and of course most commonly, elevators are symmetrical (not always though) in profile and take over a large percentage of the work in keeping an aeroplane flying when inverted.
The best example of symmetrical foils on a boat generating lift in a multifunctional desired directions (other than the rudders themselves) is a fixed, (in the vertical plane) rudder that has a, non-adjustable “T” foil attached to it below the waterline. When the boat starts to pitch down at the bow with the boat travelling forward, the T foil is angled down in relation to its forward direction. Due to that angle change, lift is generated on the under surface of that symmetrical T foil and it “pulls” the stern down (and conversely the bow upwards). The same applies when the bow pitches upwards. Lift is generated on the upper surface of that symmetrical T foil (for the same reasons) and the stern is lifted upwards (conversely the bow moves downwards) ergo pitch is greatly reduced.
This same principle applies to symmetrical dagger boards that are canted (particularly canted inwards). Due to the “pitch” of the boat, and their continually changing inclination to the forward horizontal direction of that boat, they will generate lift in a desired (at that moment) direction.
So symmetrical foils on a boat can generate lift that is “desired” in both upward and downwards directions (or side to side as in rudders), whereas “hydrofoils” on a boat will generate principal lift only in one direction all the time. That amount of lift (of a hydrofoil) is a variable directly proportional to the “speed” it is travelling. (They obviously generate some lift in the horizontal plane as well i.e. acting to reduce “leeward drift”, but that is generally secondary to their main function)
For boats, the function of a symmetrical foil is more “dynamic” while the asymmetric foils function is mainly “static”
P.S Luiz, these examples are primarily "as they apply to boats" so that the extreme angles of attack as described with planes, (there are other many and varied applications as well), simply should not be applied in this instance.

The reason most of the sailors were so inconsistent was the fact that the wind hardly blew over 5 knots and most of the racing was drifting.

The A2 is a champion downwind in the light stuff too.

The a-class rule about foils is that the maximum angle of the boards is so far angled that when the bottom of the centerboard is full inside the hull ( bottom hull is bottom board) the measured width on the top of the board is not more then 2,3 meter. This means that boat is never more than 2,3 mtr's in width. This means that you never get the extreme foils like the Icarus.

Hans

I assume curved foils are banned ?