Marc,
Neither the ISAF nor any national authority, regulates, controls, approves or even stores the various Class rules.
The governing Rules for a boat Class are usually controlled by a Class Association or a manufacturer.

There was a discussion about this several months ago and it was suggested that the ISAF could store and post all of the Class rules in a library.
So far nothing has come of it.

What are you trying to accomplish?
There has been an existing Open Formula 20 Class webPAGE (not website) since 2002.
Crazy Carl created a set of Rules in 2001.
This forum was started in November 2001.
Carl has been beating up on the rules for almost four years and still no takers.
Nothing has happened for Formula 20 racing anywhere in the U.S.
The iF20 has been a failure in europe also.

I suggest you review the previous posts on this forum and maybe save yourself alot of wasted time and energy.