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.