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Old 13 February 2011, 09:09   #21
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Just a second look at that photo an she's a stepped hull. I don't think there eligable for ski racing
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Old 14 February 2011, 03:57   #22
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Just a second look at that photo an she's a stepped hull. I don't think there eligable for ski racing
There is nothing in the rules (unless 2011 rules have changed) that says stepped hulls are not allowed.

Very interesting that stepped hulls have not really been used though. Potentially they should be really good for ski racing - if designed correctly.

On the positive side - you can generate more stern lift, create a much more level and smooth running boat. By this nature you should also be able to create a boat where the bow sections really work well and with a good bow tank will punch it's way through choppy water better than a non-stepped boat. All in all - I believe there is much potential to create a smoother tow for the skier that is ultimately quicker.

On the negative side many stepped hull designs are not so good through out the speed range - this is something I have got around by using tapered steps. Works really well is adapting stepped hulls for leisure use and leisure RIBs.

I created a model called the Aquavite SR for ski racing - but unfortunately interest was very poor from the ski race community and the boat did not get used. There is so much potential to design a better boat than they generally use - but there seems a big reluctance to change or take risks. Yes - there would be development - but all also many benefits.

Maybe one day....
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Old 14 February 2011, 06:44   #23
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Well next year is my aim!
i would love to use one of your designs,
this year i have a tow behinde a cyclone, just to prove my worth if you get me, but next year i DO intend to run a rib. I am in close contact with The BWSF and currently making sure that a stepped rib would be allowed. It would definately be very intresting to see one on the circuit and a big blow if it was to win. I intend to set it up and race it in formula 3, restricted to stock 150 engine. Also when you say about possibly not having out and out speed, i am not aware of a ski race that will stay flat throughout the duration of the race. Hopefully this might possibly work out
thanks
chris
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Old 14 February 2011, 09:05   #24
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Hi Chris - would be really interesting to do and work with you on a RIB waterski race boat. I may have another option of a stepped hull RIB that would measure by the later part of this year too.

Even though by going to tapered steps you may loose a few percent of top speed in order to gain handling - it is a small amount and I would still aim to have a quicker set-up than a non-stepped hull in all conditions.

Keep in touch and will see if we can help
Adam
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Old 15 February 2011, 16:13   #25
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T

On the negative side many stepped hull designs are not so good through out the speed range - this is something I have got around by using tapered steps. Works really well is adapting stepped hulls for leisure use and leisure RIBs.
Maybe one day....
I am little lost here, tapered steps, language barrier any other way to describe it? Does the blue tubed Rib in this thread have tapered steps, if so then might get the point. Thanks
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Old 16 February 2011, 03:47   #26
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I am little lost here, tapered steps, language barrier any other way to describe it? Does the blue tubed Rib in this thread have tapered steps, if so then might get the point. Thanks
Yes the blue boats does have the tapered steps - but not easy to see the detail.

Basically if looking in section, across the boat, most step designs are constant depth. However my tapered steps reduce in depth as you get nearer to the chine.

In effect if you are going quick the outer surfaces are having minimal input and you are riding on the inner (nearer to centreline) parts of the hull. So you are still getting the benefit of a deeper step.

However when going slower or turning or rough water and using more of the hull - the water flow on the outer surfaces is far less effected by the step as it has less depth. This gives better handling and is more predictable for most people.

Hope this helps
Adam
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Old 16 February 2011, 08:59   #27
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http://www.youtube.com/user/yellowst.../5/C9APPyM4nHs

C-Numb. I bought Adams Rib the one with hard nose, not the one on the video or the pics, but you are welcome to Stockholm to testdrive it in june. I will drive it on water home from Uk in may/june.
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Old 16 February 2011, 10:04   #28
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Yes the blue boats does have the tapered steps - but not easy to see the detail.

Basically if looking in section, across the boat, most step designs are constant depth. However my tapered steps reduce in depth as you get nearer to the chine.

In effect if you are going quick the outer surfaces are having minimal input and you are riding on the inner (nearer to centreline) parts of the hull. So you are still getting the benefit of a deeper step.

However when going slower or turning or rough water and using more of the hull - the water flow on the outer surfaces is far less effected by the step as it has less depth. This gives better handling and is more predictable for most people.

Hope this helps
Adam
OK, thanks Adam, now get a good picture! How about the ventilation of the steps, on the Mannerfelt Design boats the went holes are pretty big, is that an issue when You have the tapered steps? By the way, Your new 3B design is looking really nice so far, it will be interesting to see what speeds will be reached with it.

Joakimhansson: congratulations of Your purchase, looking great! What engine will you rig here with? And thanks for the invitation.
By the Way, do You have your crew fixed for the UK- Stockholm leg? Here one volunteer...wheeling, navigation or just ballast. The weather might sometimes be slightly brisk in May but with right gear no problem. How many days have You planned for the trip? Just had a minor job done on my knee, but should be ok by then.
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Old 16 February 2011, 13:05   #29
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150 H.O E-tec.... Sent pm to you.
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