Hull Design Question #1 - Dihedral Angle

[bob]

If I am not mistaken, I believe Sutphen utilizes a graduated or variable deadrise.

Payton,
That would be one variation of a variable dihedral angle - as you say, it gets up on plane great but instead of cutting the waves, it slaps into them - makes the bow kind of unpredicatable (or predicatable with experience I guess) as compared to a sharper bow.

Bob,
I have not spent much time with Sutphens but I will take a look. They are supposed to be an awesome boat. The only one I have seen up close was an F class boat out of central Florida.

[SHARKEY-IMAGES]

This???

[SteveDavid]

On my pleasure boat the deadrise is not constant, but is an average of 24 degrees, being more than that from the centerline of the pad (bottom of boat) and decreasing from the first strake out to the waterline.

On our Unlimited Hydroplane, we have dyhedral in the starboard sponson bottom and anhedral on the port sponson bottom. Essentially we're "banking" the boat thru the turn, while the lateral centerline is almost level thru a turn. Depending on the race course, we adjust both dihedral and anhedral, the tighter the turns the more of both and the wider the turns just the opposite.
We have aluminum I beams on the sponsons with quick change receivers for different shims. The angles run from 4 degrees to almost 0 (laterally). The angle of attack is also adjustable (running angle from sponson bow to sponson transom.

If you can make it to one of our Unlimited races, drop by the team and I'll be happy to show you around. Evansville, IN, Madison IN, Detroit MI, TriCities WA, Seattle WA and San Diego CA.

Take care,

Steve David
U-6 Miss Madison/ O Boy! O berto