Those of you who have seen Jo Richards' National 12 "Dead Cat Bounce" will have seen 50 years change in dinghy hull shapes thrown out the window! The old struggle was to provide a flat planing area for windy weather whilst also trying to have minimum surface area for light winds.
"D-C-B" has a much more Albacore-shaped underwater shape since it does its planing on the rudder wings which as they are aft of the transom effectively also extend the waterline length at sub planing speeds so the water thinks D-C-B is a National 13
All we need now is for one of you rich chaps to try a Tee-foil rudder on an Alb - we could then clean up at handicap events.
The Tee-foil rudder has the additional benefit on a National 12 of restraining the boat from what it really wants to do downwind ie nosedive at speed. At least we dont have that problem.