Out of the boats I've owned/sailed, the only one that I would say that I have experienced true planing on is the N-20. In the rough, with wind, the boat picks up and gets quiet, and keeps hauling more butt. It feels great - get set, flick it upwind a tad to heat it and drive down fast and smooth. The first time we had the boat out in a lot of wind we shot down the Bay under main only, and with every gust it pick up, get quiet, and take off.

The N-20 hull section is fat and flat aft, and the hulls are canted. The bows, although flared pretty dramatically at the deck, are pretty standard stuff at and below the waterline. The bouyancy in the bows is a wonderful thing, but maybe not so good going out through surf. Other than that I wouldn't trade them.

My 6.0 never felt like it was planing, although it is plenty fast. Rounded hulls, decent bouyancy, not as fat as the N-20 hulls. These hulls cut through just about anything, just power through it. But again, never had the planing sensation like on the N-20. Same goes with the H-20, and H-18.

So, I'm fairly convinced that most of the rounded hulls at best semi-plane (like semi-displacement, semi-planing power boats). As for the v-hulls planing when heeled - that depends on the boat. Most v hulled boats are asymmetrical - the outside of the hull is flat and fairly vertical. I believe you'd have to heel pretty far to get planing action on such a hull. A symmetrical v would give you that action, and the less deadrise the quicker that would happen - but would it be as good upwind? And the chined v, with smaller amount of deadrise will present a planing section earlier, with boards might be the better of both worlds. I'm not convinced that on a decently made boat that the dagger slots should present a lot of drag relative to everything else.

I'm very intrigued by the hull shape of the Blade F-16 - with flat sections going all the way out to the bow stem. To me, the Blade is to the T-4.9 as the N-20 is to the N-6.0. Although I've not sailed the 4.9 or Blade, it appears that like the 6.0 and N-20, there are times when the 4.9 is faster, but on the whole the Blade is the faster boat. The main differences being the flatter hull sections.