CDMA
05-26-2000, 02:54 PM
Spent an orientation day at the school I am going to next year ( Webb Institute of Naval Architecture). It was wild. I spent the morning with a student who is doing a thesis about ventilated props. A high performance propeller with a " step" in it. Really cool. The top part had less pitch to aid holeshot and then as RPM increases the other part after the step takes over with more pitch. Also for the same principle that makes a car drafting another go faster the toal resistance of the blase is less. Wild design. Then even better the last part of the day was spent with a Senior who helped me work out the effects of putting an OB on a bracket off the back of a 18 2+3. Taking into consideration hull width, depth, and deadrise we actually computed with some wild formulas that I do not pretend to understand. We found the actual effect of the change in weight and center of gravity. Actually the righting arm with the lighter Ob was very close to the same specs as a standard inboard. There was qite a bit of estimating but then we checked it. We found a 38" model with a 24 degree deadrise and simulated in the indoor tank the affects of the changing weight while this model was actually in the water!!! What an experience. So it seems while our measurements were not so exact that an 18 with an outboard might work. Sounds like a interesting idea. With a 300 Pro max someone might even challenge Geoo.
Chris
Chris