planing theory

I can tell you from experience that the flow will remain 3D unless you add lift strakes that channel the water. That helps to lift the boat at the transom, decreasing drag and increasing speed.

I wouldn't trust a computer program that I myself haven't constructed, or guided a colleague to construct. Too many unstated and illegal assumptions are built into computer codes.

The fastest boats, race boats, are not designed from any known principles (of which there are too few to be of any use) but by seat of the pants engineering, by trial and error. I raced for 12 years, now rework racing propellers.

 

I agree 100%: it is a very tough hydro problem.
There are a few papers describing results for 3D planing around but they
aren't all that impressive (except for the pretty graphics and animations).

I have seen some work that uses vortex lattice techniques, but I am
suspicious of them for a variety of reasons: e.g. I know how poorly they
behave for some simple planar wings in free air, so they are unlikely to
be better in the presence of a free surface.

Fortunately, I am more interested in the numerics of solving given
equations, e.g. the "planing equation" or the "lifting surface equation".
Engineers and practitioners can suit themselves

I meant 3D in the sense that the local flow on a high-aspect ratio wing is 2D, except at the tips.

 

Hypersonic, yes, but it also requires a rarefied atmosphere. Newtonian flow is found where the mean free path of the molecules is large compared to the size of the body. This environment is encountered in reentry problems.

The most probable speed of an air molecule at sea level conditions is on the order of 400 m/sec (http://plaza.ufl.edu/jgu/public_html/UF/AirMolVelDistr.pdf), and 500 m/sec for the water (http://www.uic.edu/classes/phys/phys450/MARKO/N003.html). So the freestream mean flow is only a small shift in the velocity distribution of the molecules. They are still hitting the surface from all directions.

Planing is a completely different situation. The density of both the water and the air is high enough that they are best approximated by a continuum. Not only are the molecules not hitting the surface from a fixed direction, the continuum flow at the surface has zero velocity relative to the surface (no-slip boundary condition). The boundary layer is formed by the difference between this no-slip condition and the outer freestream flow.

 

Now we're getting somewhere...

 

Picking which type of planing hull design to use depends on the type of propulsion system you want to use. With a constant deadrise or monohedron hull you can use all the propulsion systems etc Inboard shaft, Inboard leg, Out board and Jet.But with variable deadrise or warped you have two propulsion systems Inboard leg and Out board because you can trim them. And you will need to use trim with a variable deadrise or warped hull.

 

Our updated page for POWERSEA:

http://www.mainemarinecomposites.com/powersea

Validated from various sources including tank tests and one of our associates' CFD experiments, e.g.:

http://www.youtube.com/watch?v=HmtOAtvZD7w&feature=results_main&playnext=1&list=PL6ECBF2A1F9F733D5

Paper attached from one of the investigators on the project.