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Re: A-class, "hydrofoils not permitted" violated? [Re: Wouter] #150269
07/23/08 03:35 PM
07/23/08 03:35 PM
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Atlanta
bvining Offline
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Place the daggerboards under a 10 degress inward angle and have the hull both canted outward by 10, ehh voila according to the whigs at ISAF this boat is not using any hydrofoiling effect to lift it out of the water. Because the starboard daggerboard in in line with the port hull centreline.


I'm pretty sure that the rule reads that each board has to be in line with its own hull centerline.

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Re: A-class, "hydrofoils not permitted" violated? [Re: Rhino1302] #150270
07/23/08 03:54 PM
07/23/08 03:54 PM
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South Carolina
Jake Offline
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you have two hulls and two centerlines...no problem.


Two non-parallel centerlines? How do you define centerline?


That was kinda my point. My boat's hulls are canted outward. As you look at the bows, they tilt inward at the top. The daggerboards and rudders are in line with the plane of each hull such that the hull, the board, and the rudder of the leeward hull is nice and plumb when flying a hull...many a-cats are that way (and so is the Nacra 20). I was just pointing out that it's tricky to define all this stuff...including what the vertical plane of a hull is.


Jake Kohl
Re: A-class, "hydrofoils not permitted" violated? [Re: Jake] #150271
07/23/08 04:05 PM
07/23/08 04:05 PM
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Posts: 256
North Europe, Sweden, Uppsala
Hakan Frojdh Offline OP
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Hakan Frojdh  Offline OP
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North Europe, Sweden, Uppsala
One way of doing this is to remove the hydrofoil and min board tip distance rule and require that the centerboards and rudders must be straight and enter and exit the hulls through the centerline and that they are flush with the hull when they are fully retracted.

I guess that solid wings should be stopped also by require a min soft sail area or something like that.

I'm not sure how we should handle the case if someone shows up with a kite on their A-class.....

Or it's maybe time to try to find a single handed one design class, that is light, fast and has big turnout at the regattas. Any suggestions?

/hakan

Last edited by Hakan Frojdh; 07/23/08 04:06 PM.
Re: A-class, "hydrofoils not permitted" violated? [Re: Hakan Frojdh] #150272
07/23/08 04:46 PM
07/23/08 04:46 PM
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Posts: 1,226
Atlanta
bvining Offline
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Hakan

I think you are overreacting.

Ben's solid wing sail wasnt faster. No need to add a rule to legislate solid wings.

And so what if banana boards are faster? Adding them isnt going to be a big deal.

The CClass guys already proved that a foil borne boat isnt as fast as a catamaran with hulls in the water. So, the slippery slope to full foil borne cats wont happen, that experiment has already been done.

I dont see how adding a new curved daggerboard is going to make the boat worse. If you leave it in the current position it will help get the sterns out of the water downwind. Tell me why this is a bad thing?

A foil assist looks to be faster, but again I think thats were its going to stop. Go back and review the CClass experience, and then have a glass of wine and relax, its going to be ok.

I say we get rid of the "no hydrofoil" rule so all those off center daggerboard boats wont be obsolete.

Bill

Re: A-class, "hydrofoils not permitted" violated? [Re: bvining] #150273
07/23/08 05:21 PM
07/23/08 05:21 PM
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Posts: 1,307
Asuncion, Paraguay
Luiz Offline
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Anybody got a copy of ISAF Equipment Rules for sailing?

Look up hydrofoil.

Then look up daggerboard and rudder.



I just did that.

The daggerboard is defined as "a retractable hull appendage, attached aproximately on the hull centreplane and not rotating, primarily used to affect leeway".

The rudder is defined as "a movable hull apendage primarily used to affect steerage"

The words "hydrofoil" and "foil" are not present in the document.

The axis are referred to the waterplane with the boat in measurement trim, not the waterplane when moving.

I see nothing there very helpful to prevent lift generating devices.

All the best.


Luiz
Re: A-class, "hydrofoils not permitted" violated? [Re: bvining] #150274
07/24/08 08:30 AM
07/24/08 08:30 AM
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Posts: 548
MERRITTISLAND, FL
Matt M Offline
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Quote

I'm pretty sure that the rule reads that each board has to be in line with its own hull centerline.


The resticted rule set does pretty well to keep this in check - even if they neglected to publish it on the site.

No one seemed to upset about canted boards. A curved one with the same inboard and outbord limits keep the thing virtually identical in net force. It is impossible to restrict the board to be on a hull centerline as you then have to write a rule about the shape a hull can be as there may not be a centerline on an asymetrical hull. If you cant a symetric hull and put the board in straight, they are in effect now canted. Straight foils canted foils and limited curved foils all produce some lift forces. This is why the technical committee removed the hydrofoil reference and in its place restricted the limits of the foils.

These boats have been measured and allowed to compete, so for the time being the argument is moot. There are several petitions being submitted to address this and it will go through the proper procedure to be voted on by the class and potentialy have the rules rewritten to address it.

Re: A-class, "hydrofoils not permitted" violated? [Re: Matt M] #150275
07/24/08 09:04 AM
07/24/08 09:04 AM
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claus Offline
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Say you could build a 50 kg A cat with 25 kg of movable weight added which can be displaced to windwards with a sheet. Would this fit the current A class rules?

It all boils down to the question if the A class really wants to be a development class or if at some point it just wants to abandon certain developments, which requires more and more restrictive class rules. The foil/wing is a secondary, although actual, issue, imho. More issues to come, for shure.

Re: A-class, "hydrofoils not permitted" violated? [Re: claus] #150276
07/24/08 09:29 AM
07/24/08 09:29 AM
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Posts: 3,116
Annapolis, MD
Mark Schneider Offline
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Hmmmn... did the A class experience the recent growth spurt because lots of sailors discovered they liked designing and building faster sailboats to race and joined the class and built or bought the latest design ...

Or did the A class grow because a lot sailors wanted a light weight, high performance single sailed boat with great international sailors at the top of the list and got a boat to play?

I know I waited to see how the class dealt with the foil issue the first time.... If they had voted Yeah on the disruptive foil technology... I would have waited and bought a boat for 1/3 the price.


crac.sailregattas.com
Re: A-class, "hydrofoils not permitted" violated? [Re: Jake] #150277
07/25/08 10:16 AM
07/25/08 10:16 AM
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Posts: 805
Gainesville, FL 32607 USA
dacarls Offline
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Re Jake's A-cat AND MINE TOO: "My boat's hulls are canted outward, bows tilt inward at the top. The daggerboards and rudders are in line with the vertical plane of each hull such that the hull, the board, and the rudder of the leeward hull plumb when flying a hull".
So--- the newer boats have the boards tilted in, so that they get lift from the boards when heeled at speed, a big advantage when doing the Wild Thing. To add insult to injury, it appears that inward canted banana boards provide even MORE lift.
By the way---- Lift = hydrofoils


Dacarls:
A-class USA 196, USA 21, H18, H16
"Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison
Re: A-class, "hydrofoils not permitted" violated? [Re: dacarls] #150278
07/25/08 11:35 AM
07/25/08 11:35 AM
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Posts: 12,310
South Carolina
Jake Offline
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Dave,

Come on...what would you know about the subject?


Jake Kohl
Re: A-class, "hydrofoils not permitted" violated? [Re: dacarls] #150279
07/25/08 11:45 AM
07/25/08 11:45 AM
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taipanfc Offline
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I have one of those Flyer 2s from Ashby which have the tilted in c/boards. One day got lazy and didn't bring the boards up and found going wild I could push a lot harder up to about 15 knots of breeze. The lift was good enough to help to keep the bows up and allow you to sit a bit further forward. Which meant the stern didn't dig in as much and in chop less rear beam slap. Above 15 knots you would want to bring the boards up as you wanted the sideways slip as the lift generated wasn't enough. But 8 to 15 I always keep down. At the Florida worlds only brought the boards when sailing flat and felt I had really good pace downwind.

This is my experience, and normally sail myself and use a velocitek to guage performance. The averages were better doing what I described for how I sail the boat.

Re: A-class, "hydrofoils not permitted" violated? [Re: taipanfc] #150280
07/25/08 04:33 PM
07/25/08 04:33 PM
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Atlanta
bvining Offline
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The issue is being put to vote by the membership.

The wording is specifically for or against "curved foils."

This doesnt solve the question of whether straight daggerboards that are not in line with the hull centerline are legal or not.

Re: A-class, "hydrofoils not permitted" violated? [Re: bvining] #150281
07/25/08 07:42 PM
07/25/08 07:42 PM
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New Hampshire, USA
windswept Offline
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Bill,

I would think that Canted boards and curved boards would be viewed and treated the same way. That is how I responded to the vote anyway. if canted boards which are already in use throughout the class, then banana boards should be too. As to obsoleting the whole class, my Boyer is probably close to being there anyway. Where I think this will effect the class the most is those who own newer boats.


Tom Siders
A-Cat USA-79
Tornado US775
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