The rules now state that sails have to be built out of just one cloth throughout the body?

When trying to look up the rules, this is what I find on formula16.net




Choosing to ignore the warning, I go to the ISAF website and find this as the current rules (2012 rules): http://www.sailing.org/tools/documents/F162012CR220612-[12620].pdf

I find nothing there about sail materials under section C.10 - Sails.
Under section G.3.4.b I do indeed find this regulation: The body of the sail shall consist of the same woven and/or laminated ply throughout

Does this mean that new string sails or not allowed anymore? Any changes to previous rules would be marked in blue or red. This text is not marked so it should be a relatively old change (2011 or 2010). Why would string sails not be allowed? Cost?

Further I have to ask myself where the current rules are to be found when considering the text on the class website.




I suppose you would get 6deg + the angle you get from flying a hull and then solve for lift generated at different heel angles and different attack angles on the daggerboard after compensating for increased hull drag.

About 17kg

So how does that translate into useful performance?

Does anyone know why 6 degrees was decided upon as a rule?

Aido,
There has never been any restriction on materials for build or sails in the F16 rules. If there is somewhere now, it was not approved by the class.

It was done to allow for some development. This allowed for some experimentation but limited the range to a point where it would be unlikely to be any significant disruption to the class stability to have the feature or not.

The 6 degree point also provides a range to avoid nit picking various boats at the time of measure. What are not addressed in most other class rules on this subject are the various tolerances involved in a system. It sounds all nice to say things will be inline or vertical. You have builder tolerances, which if you measure some brands /models can vary quite a bit.
Look at the F18 rules, the boards must be inline with the CL of the hull. The front beam must be straight, but can have the dolphin striker tensioned to provide a prebend. If you have straight hulls and inline boards but tension the striker to full range of the rules, you now have something around a 2 degree inward cant on your boards. You can have more if you play with the trunk stops and who measures this when doing a cert on a boat?

I have now tried canted boards in my "almost" F16 for two seasons and are quite convinced they are worth looking at. The A class only went to curved boards to circumvent their rule dictating that the top of the board should not go outside the hull when in the up position, we don't have that problem and are probably able to achieve the same with the straight board. One only has to look at the Nacra F16 to see a manufacturers take.

We are missing a trick in not allowing A Class rigs for the single handers, very refined with a long history of development, they are readily available and seem to be superior to the rigs designed for dual handers we are left with using. Certainly I wouldn't go back to my old rig even though it is 1 1/2 metres smaller.

http://carbonicboats.blogspot.com.au/2013/06/alphabet-soup.html

If this is correct, monkeying around with foils could be a cheap way to increase performance rather than buying a new boat.

Pete see A-Cat development for this. As lifting foils were added to the platforms, changes to the hull shape were done in the transom. If you went full flying you could avoid this but that isn't the intent of the F16 class rules as I see them.

The average sailor is going to get more out of regular sailing and practice than monkeying around with foils, at least not building foils. I decided against it as my existing hot box fits my 66" long boards and that is it.

PGP,

You wnat to buy performance, then you should get into something with a motor.

Long foils, curved foils canted etc all have the POTENTIAL to add a small bit of performance in some given and usually narrow range of conditions.

Long boards now need to be constantly adjusted, curved foils require quite a bit more crew athletisism and skill etc. Improperly tuned or used features are slower. These things just make the good sailors maybe a bit better in some conditions, and the sailors who now have more than they can do to run their simple boat anywhere near optimum are even further behind.

Wayne,

We have Falcon's around with canted boards and we have Falcon's with straight boards. I have sailed both and have not seen a performance difference when looking at the results.
So I don't think the difference is huge.

Gill

Agree with there being little difference at this time, but !

What I do find with my boat which is probably quite low volume compared with the later generation boats is that at higher speeds the inclined foils do generate some lift, one only has to move my butt foward or back 100mm ( altering the AOA )to see the difference of how the foward part of the hull is higher in the water.

What I think also happens is that this negates the need to trap out with the spinny up, the boat if heated up and the speed increased to a point where the lee hull is high in the water, will go downwind just as well with me either sitting in or trapping. I'm not sure why but I think the extra loading on the lee hull from trapping, causes the lee hull to submerge more and thus drag over comes the advantage.

With the much fatter latter generation hulls I think there is enough volume ( width ) to create a form of "planing" which in effect is already making the hull a foil. Those wider hulls trying the inclined board are very much first generation ( the Nacra F16 is starting to move things on with their long high aspect boards ) and due to the ventilation issues we are seeing ( just like the early moth tube vids where they had to incline the board a few degrees ) plus lack of adjustment to best set up a boat,are probably not good examples to be using for justification of or not of , foils.

What if we can generate planning and lift and get it useable. I think this is where the A Class is heading, I personally don't feel they have got there yet but with the new S boards such as the Carbonic boats, they stand some chance.

But we on the other hand have some advantages that the A's do not. We have a rig which is much more powerful than the A's to utilse foils better. We have no max or min overall board rules so we can move the foils outwards or even have the top of the withdrawn boards wider than our max width. We have an extra pair of hands to operate the foils better ( see the Phantom 2 http://www.youtube.com/watch?v=5doBIv3TVbA&feature=player_embedded to see what can be achieved ), we have a jib which balance the boat better upwind, we have a very large spinnny for downwind, we are wider at 2.5m and I could think of other reasons as well.

Sooner or later someone will pop us the myth of expense of the S Boards or C boards. Virtually all board moulds are now CNC machine cut. Machines do not care whether it is a straight run or constantly arced, it just another point in time that the machine head must reach. So yes the mould may be marginally more expensive but only marginally. Yes there will be more carbon to strengthen the board due to it now effectively lifting and carrying weight, but that extra material cost in the whole scheme of things will be only a small part of the total cost. At the moment the A class boards are falling in cost as more and more manufacturers are coming into the market.

So do not diss foils, they are the future, perhaps not fully foiling but certainly foil assist in our case. Perhaps we as an semi experimental class should be allowing any board shape or size, the privateers will experiment and the manufacturers will lag behind as usual but we will modernise as we go along, making the class much more appealing to all.

Basically I agree. I think upgrading an existing boat protects the owner's investment.

Yeah, thats the way i see it too. I'm thinking because of that, the new restrictions wouldn't be valid????

Back to the center boards. If you twist the boards in the case that would give you even more lift with straight canted ones wouldn't it?

17 kgs is crap need about 260 kgs at least.

Adding my two cents. Sailing catamarans for 30yrs, current owner of an f16. Last weekend I got an opportunity to sail a F20c in 12-18 knots of breeze. The boat did jump out of the water on us a few times up wind. A fun experience but not a fast experience.
Downwind, single trap conditions, the curved boards created a special ride. The boat was not foiled up out of the water, but from the dagger board well to the bow she was clear of the water. The speed was in the 21 knot range. Steering got super sensitive because it felt like any turn of the tiller was not turning the hulls, but rather pivoting the boat on the curved board.
Overall I really enjoyed the curved board experience.
The phantom project might prove curved boards are outdated shortly?

Like Tim, I am short on money and time. But if my F16 manufacturer came out with a curved board package(kit) that was tested for the F16, granted non class legal, and the price was not ridiculous, I would go a head and make the change.

I am finding the biggest limitation with the F16 is the length. I solo the boat mainly, and really feel comfortable in pretty high wind conditions. It is the sea state, wave conditions that will cause me to back off sooner then I would like too. I wounder if the curved foils would improve the F16 ability to handle rougher wave conditions?

with straight (canted) boards the vertical lift will always be directly proportional to lateral lift. The total lateral lift (across all boards, hulls and rudders approximately equals (total righting moment) / (0.45 x Mast height). On a modern cat approx 70% of this lift can be attributed to the leeward daggerboard. Then it comes down to basic trigonometry and vertical lift = lateral lift x tan(angle of board + angle of heel).

260kg is more vertical lift than the required lateral lift so a straight board would have to be canted more than 45 degrees.

F20c sounds like a sweet ride need to get on one

T-foils on the rudders. A lot less work than curved foils. i think they would make a tremendous difference in the short lumpy stuff especially on the finer bowed boats like the Blade.

Anything new? Was there a class meeting at Racine?

There was and I think the consensus was to leave the rules alone.

Were the minutes published anywhere?