Going faster than hull speed without planing is called "forced mode" and cats are doing that any time they have their transoms depressed but not submerged, indicating that they are making a longer hole in the water than their hull length, and they are sailing 'up' out of this hole. Conventional lead mines don't have the power:weight to start climbing out of the hole the way cats do, and 'hull speed' is the point at which one enters forced mode.
