Breaking the wave Barrier:
Like any design, we need to establish the parameters first. The new breed of cat has a unique requirement in that it has to operate in three modes. Typically, the mistake has been to design for displacement mode only a la slender monohull.
However, to my way of thinking the boat operates in two distinct modes and if designed for these, it will be likely that the planing mode can be encompassed too.
Below hull speed, designs are known and refined.
At hull speed, the boat is sitting in a trough, because the water has to speed up to squeeze around the boat, and because of the increase of velocity, there has to be a decrease of pressure, sigified by the lower water surface, or trough. The problem is that the trough further restricts the waters path, so it has to flow still faster....
In this mode, it is obvious that any rocker or vee to the hull is bad. (The water rushing abeam from under the hull "vee" must lower pressure and sink the boat still deeper in the trough, similarly the water flowing aft under the hull rocker, or "around" the prism)
A flat bottom and sharp edge exploits the pressure at this depth and slows spanwise flow, maintaining lift (buoyancy). What now exists is a boat that accelerates the water only around the sides of the hull, so it is bad at low speed, but not that bad.
Once hull speed is exceeded, I guess the shape of the hull needs to be more like a submarine, because it is no longer "benefiting" from the surface interface? Or perhaps in laymans terms, "the water doesnt have time to get out the way"
Before trying to develop numbers, I guess my supposition is a deep, narrow, flat bottom. The bottom in plan section would be submarine like (stretched tadpole profile), and the deck, wedge shaped (pointy end forward) I doubt there would be merit in a stern taper. I don't yet know if these shapes can mary,without excessive wetted surface,(deep hull) but it seems that the two distinct shapes will be in their mode (submerged bottom section stays effectively submerged, and wedge shaped top not contacting water after hull speed.)
Anyone out there know more about post hull speed hull design? Is it a misunderstanding on my part, or are we typically neglecting this mode?
The advent of the F14 class will force this issue, and
