Forced air ventilated stepped hull?
12-04-2005, 08:22 AM
#21
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Re: Forced air ventilated stepped hull?
Originally Posted by Mark Mathews
Yes I agree....Just repeating what I was told.
You should contact Mark Spates at Extreme or Will Smith at Phantom. They will have more insight.
You should contact Mark Spates at Extreme or Will Smith at Phantom. They will have more insight.
Things that work best for a personal fast powerboat might not be the best compromise to a racer on big water.
For me, I'm thinking lake boat - one that could hand the LOTO channel on a July 4th weekend.
12-04-2005, 01:14 PM
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Re: Forced air ventilated stepped hull?
Winning a race with two identical boats, (except that one is ventilated and the other isin't), doesn't prove anything, except that the crew of the winner, the propellers, the wind and wave conditions, all contributed to who won and who lost.
The only way to prove that ventillation is better, is to run two identical boats (in every way), 100' apart, on a course, and record performace thruout the endurance of the run. Then you have to do that again, 2-more times, and average them out. Tony
The only way to prove that ventillation is better, is to run two identical boats (in every way), 100' apart, on a course, and record performace thruout the endurance of the run. Then you have to do that again, 2-more times, and average them out. Tony
12-04-2005, 05:49 PM
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Re: Forced air ventilated stepped hull?
That hull was built by Jack Domic at hydra power poats in Toms river NJ. It was rigged by its owner with a single crate Hemi motor. Last I had heard it was running in the mid to upper 80s
12-04-2005, 10:20 PM
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Re: Forced air ventilated stepped hull?
"When air is induced under a platform (hull), it acts like a hoovercraft"
not the same...an engine supplies the thrust in this application. along with other important designs characteristics.
reducing surface tension and inducing air are different.
you can not have a 'forced air' system if you vent it to atmosphere...this will = NO pressure and NO lift!
not the same...an engine supplies the thrust in this application. along with other important designs characteristics.
reducing surface tension and inducing air are different.
you can not have a 'forced air' system if you vent it to atmosphere...this will = NO pressure and NO lift!
12-05-2005, 01:07 AM
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Re: Forced air ventilated stepped hull?
If that's true...I wonder why so many boat manufacturers are using this principle...just look at the other replies to this thread....and all the boat names...like Donzi for example.
12-05-2005, 08:31 AM
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Re: Forced air ventilated stepped hull?
Not many more people have spent more time than me under a donzi??? i must have missed the holes!
i guess i need to mount a huge funnel on the bow with a hose going to the bottom....LOL
i guess i need to mount a huge funnel on the bow with a hose going to the bottom....LOL
12-05-2005, 08:55 AM
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Re: Forced air ventilated stepped hull?
When a boat is 'up and running' it doesn't require any additional ventilation. Only when the step is submerged is it of any value. We used a drilled tube as the rear frame on the steps of the aluminum Cougars, but just to break the suction getting on plane. When the outboard edge of the step clears the water, the step is naturally ventilated.
12-05-2005, 12:41 PM
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Re: Forced air ventilated stepped hull?
Actually...I didn't think Donzis used ventilation either...it's just what I've read on OSO chat lines. Either people are making up stories...or maybeee...some were built with ventilation. I personally... have never seen them on any. Who knows....?
And yes...ventillation is only effective... from a dead start to just past planning speed. You'll get on plane at about one third the normal time it usually takes. And in a race...that would get you in the lead...out of wakes...and a better chance at winning.
And yes...ventillation is only effective... from a dead start to just past planning speed. You'll get on plane at about one third the normal time it usually takes. And in a race...that would get you in the lead...out of wakes...and a better chance at winning.
