jet power on warped bottom hull?

[nbehlman]

I am planning to build a 14 foot runabout in the style of the early 30's and 40's chris crafts. The power plant is a 70hp TigerShark jet ski motor and pump. I am designing the hull from scratch and I wanted to see what the experts on this forum have to say. If you have any comments or advice on what types of design features I should incorporate into my hull, please share them! Here is some basic info:

http://nbehlman.com/hullprofile.png
length: 14ft
beam: 4.8ft
weight: 650lb (jet ski weighs 476lb)
deadrise: 6.5 deg
draft: 6.5 inches (one person aboard)

Are there any special considerations I should take into account when designing a hull for a jet drive? These hulls are meant to take an inboard prop. I have noticed that jet skis have a much more rounded hull, while my boat will have sharper chines and a low deadrise vee bottom.

I have looked around on the internet for similar projects and there seem to be quite a few. Most of them are simple "what happens if I do this?" type projects. I came across one site that shows a very strange profile below the waterline:

http://www.sponbergyachtdesign.com/D...le%20small.jpg

It looks to me like it would create massive amounts of pressure drag because of the keel line near the intake.

I found a video of a chris craft converted to a jet drive:

http://www.youtube.com/watch?v=uBUUeNfGjTg

At the 10 second mark, you see it go into a drift turn characteristic of jet boats. I am concerned that these kinds of turns could cause the hull to "trip" over the nearly square chines.

I expect that my hull will provide a great deal more lift than the jet ski hull, but will of course weigh more. I have done quite a bit of work with the Savitzky power prediction method, but I suspect it is not very accurate for jet boats since the kind of suction onto the water. My target speed is 30 mph. The jet ski currently does 40 mph.

[Boat Design Net Moderator]

Crossposted; let's keep the discussion together in one thread at
Jet power on warped bottom hull?