I doubt that it will disrupt the IRC that much, because it probably takes into account the length of quarter buttocks. A scow has much longer quarter buttocks than most pointed bow monos. Sail carrying ability is quite closely related to quarter buttock lengths. With a scow bow, it is possible for the quarter buttock to be longer than the at-rest waterline. I imagine the IRC also takes into account the weight of the boat.Im sure a Fantasia can do 20+ knots if you can find a steep enough wave to surf down. 17 knots is a good speed, it does give an ability to cover some distance. I prefer the look of the bow on the Ace 30, it appears to lift more. Fun project for sure. Wull you be documenting your build?
A quirky plywood rocket with sawn-off scow bow - can the Ace 30 disrupt the IRC racing scene? - YouTube
An alternative to the scow bow is the apple bow. This is when the maximum beam is so far forward that the bow (in plan view) has an almost semi-circular shape. Joshua Slocum's SPRAY was like this, But it was quite heavy. It did, however, have an excellent course-keeping reputation. He sailled it around the world alone with no self-steering vane, and no engine.
An apple bow has a lot of tight, compound curves, and is relatively difficult to plank up. But it is an excellent shape for fiberglass.