Yes B-Class is a box rule. The specs are max LOA 20 feet, max beam 10', max SA 235 ft^2. The original Tornado was intended to be the ultimate B-Class racing machine.

Prindle was named after Geoff Prindle, who thought the H16 needed more bouyancy.

There's a legal organization called NACRA. Put NACRA through google.

Exploding Beaver? Almost sounds pornographic.