Hi, can anyone explain me a few rules please? English is not my first language and some part are not clear to me

"The dagger board boxes and the rudders have to be in the vertical plan of the hulls."

1-Can the boards and rudder be inclined either inboard or outboard or they need to be perfectly vertical in relation to the hull?

2-If need to be vertical to the hull, can te hull be inclined in relation to the vertical of the boat ?

3-Is it possible to have gybing or otherwise orienatable board?


"All underwater appendages must be symmetrical."

4-Does this mean that each hulls need to have the same appendages or that the section of appendage must be symmetrical ?

5-Does one hull need to have both of it's side identical?

"A.5. SPIRIT OF THE RULE
In case of doubt, the intention of the rule makers, which is the spirit, shall take precedence
over the letter of the rule."

6-Is it against the spirit of the rules to gain vertical lift by other way than hull forms?

"For the construction, only the following materials are authorized : polyester or vinylester resin,
glass fibres, core of PVC or balsa or felt, the combination of wood-epoxy"

So epoxy is allowed when joining wood but not for laminating fiberglass, am I right? What about covering wood with light fiberglass?

Thanks, I know that this is a lot of questions. I curently have some free time (cruising the east coast) and would like to start designing one of those little boat

1. they need to pass through the top and bottom centreline of the hull.
2. yes
3. yes


4. each appendage (rudder or foils) must be symmetrical around its own centreline.
5. I don't think so contact your local measurer for confirmation.



I'm guessing yes.



I think you could use epoxy when covering wood but again would consult a measurer before committing funds.


Good luck and enjoy your trip. Post some drawings when they're done.

It would be a good idea to check all the questions with your measurer.

Thanks for that quick answer! I will certainly confirm everything with a measurer before building anything but your help will allow me to at least start thinking about it

The reason I asked some of these question came after reading
http://www.f18.nl/index.php?option=com_content&task=view&id=30&Itemid=46

The description of the foils say:

"The jibing daggerboards work as they are supposed to do and lead to very good pointing angles. In choppy conditions the hulls pierce the waves, and the boat does very little pitching, thus leading to stable flow in the upper part of the main sail. When reaching the hulls are fully planning. Lift is provided by the flat underwater bow section and the leeward daggerboard - mounted at an inward angle of 10 degrees relative to the hull - and is sufficient to lift the leeward bow about 15 to 20 cm out of the water!!

Your interpretation of the rules are what I tough but this model seem to go differently, anyone have an explanation for that? A gybing board at 10 degs inboard on a boat that is canted can make an interesting lifting foil and if allowed this is a possibility that I would like to develop

Without going to your link, I'm guessing thats out of a review of the prototype capricorns. The canted boards were outlawed before it went into production.

That would indeed make sense, is it a suposition or a know story?

Thanks
Guillaume

which part? That it was a review of the capricorn, that the bows lifted 15cm or that the rule was changed?

That the canted boards were outlawed before it went into production.

But I think it's an error of understanding on my part. So the rules is relatively new and the prototype was made before the rule, am I right?

The only relevant question left before I can start some sketchs would be to know if both side of the hull have to be identical. If not needed, as suposed here, then I would need to know how the class determine a centerline on an asymetrical hull with no hard edge.

I'll try to get in contact with an official measurer, if someone happen to know one who is willing to help me by email please let me know

Guillaume

First prototype Capricorn had Hulls canted outwards with boards canted in. Canted baords were quickly banned in the F18 class.

Ok, make things clear

This is exactly what I would have done, now i'm trying to figure if there's a way to play around the rules to get similar effect with asymetric hull, but it is probably not worth the complication since anyway the rudder and the board have to be in the same axix...

but still if someone can confirm the acceptance of assymetry for the hull, it would be nice to know

Guillaume

I am fairly critical about the vagueness of the F18 rules. I have problems with the wording of the rules that you mentioned and a few others.

The material list is very vague about epoxy. It could be read as allowing the combination of wood and epoxy, or as allowing epoxy on wood. The use of the hyphen is not really useful in this case. Worse, it mentions "epoxy glue" and "epoxy resin" as allowed. These uses only confuse the context for epoxy use because in one case it specifies a type of epoxy -- resin -- and in the other case it refers to its usage -- gluing.

Probably 15% the parts on production F18s violate the rules about materials anyway. For example, rudder castings are made out of non-extruded aluminum. Take inventory of small parts and not how many are not made out of the materials above.

On lifting appendages: The rules state that "The dagger board boxes and the rudders have to be in the vertical plan of the hulls."

1. Because the rules never specify that the hulls need to be symmetrical, there really is not vertical plane of the hulls. The rules do not refer to the vertical plane of the boat or else the Infusion would be illegal with its canted boards, rudders, and hulls. At best, this might require the dagger board boxes and rudders to be in the same plane. But, that is reading a lot into the rules.

2. This is the dagger board boxes, not the daggers boards themselves. The boxes do not really have to by symmetrical, so they do not have a plane that can be used for reference.

3. The rules only talk about dagger boards. However, the rules allow centerboards. So it would be possible to have centerboards in any orientation.

Spirit of the rule and lifting with appendages: The spirit cannot be to disallow lift from appendages in general. When an F18 flies a hull with the bow up, the boards are lifting the boat because they are no longer vertical.

I have a very low opinion of "intention of the rule makers" rules.

1. Their intensions are not written down. If they were, it would (should) be in the rules.

2. Who are the rule makes? The current chief measurer? The measurer when the rule was passed? The representatives? The voting members? Do we need to poll all of the rule makers to find the intention?

3. This kind of rule is only needed if the rules are poorly constructed. Many classes have been able to write good rules sets of rules that do not require ESP to know the intention of the rules.

I have similar problems with the "what is not expressly permitted is prohibited" rule. A few critical parts on the boat are not expressly permitted. For example, unlike the rest of the standing rigging, guy wires on the spinnaker pole are not expressly permitted. Strikers are not expressly permitted.

I have a VERY long list of other issues with the rules too. But, they have less to do with the topic.

That is good to see I am not the only one having some troubles with them. Altough curently I am orienting my design on quite standard features to get some feedback of the platform before trying to inovate so it is not too problematic. But still I might try a few ideas if things were more clear.

I am still searching for someone who could provide answer to some of these question, please let me know if you know. Also if any online publication give more details than what is available on official site, I would like to get a look.

John Williams is the national measurer for the North American F18 class association.

Pierre-Charles Barraud is the international class Chief measurer. The class rules say that if you write to him he will reply within 30 days.

Check f18-international.org for contact information.