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Old 26 February 2010, 05:37   #81
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Sorry Chewy, that was a bit obtuse, the rails differ on the steps as does the deadrise and the anticipaited running depth of each section we have placed the rails to try and be right for each section to provide stabilaty and reduce drag when running.
As Cookee says the rails in the boat will be sacraficial so we can remove what is not needed but I am sure they are about right.
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Old 26 February 2010, 05:43   #82
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Cheers for that, so the placement is more dependant on the actual step they are to be fitted rather than the position of the rail on the step in front, if that makes sense?

I have quite a few "obtuse" days on here!
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Old 26 February 2010, 06:33   #83
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spray rails

first of all thank you for shairing your build with us
how have you determined the size & the placement of the rails . did you use a scale model in a tank or calculation .most manufacters seam to have spray rail because they have .it is the same as the hull shape why a deep v why a shallow v . what angle is best & why when you ask these questions at shows no one seams to know with an enginering ansure
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Old 26 February 2010, 10:27   #84
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OK first off this is all my opinion and as such can be disagreed with if you wish.
Hull design is always a compromise.

Deadrise, or v angle, shallow v makes for a faster hull but harder landing, deeper v makes for slower but softer.

Rails are there to deflect water and energy away from the hull, mostly down if you can.
There is a high(er) pressure area developed at the hull water contact point, anything above that is in the air and as such useless ( unless you are looking at aerodynamics)
Most of the stuff below that is drag and therefore a hindrance. Trouble is the bloody water never stays in the same place, so this area moves around on the hull so you have to balance that to try and make the boat do what you want it to. SIMPLES.

We do have a scale hullform for this boat and if you want you can see some of the video on youtube search kitten268 and see the dart vids.
You canít get data for a planning hull from a model, basically you are trying to balance the weight of your boat on a small patch of water that is wobbling about, even in a test tank with loads of money to spend the variables are too great. What you can get is a very good feel for how the hull is going to handle and any nasty/nice characteristics it is going to have.
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Old 09 March 2010, 08:41   #85
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It's been a while, getting close to getting the hull mould done now - the formica sides are on now and work is progressing on making all of the corners razor sharp and making all of the bits where everything joins up smooth.

Kitten has also removed the extension on the transom so that it will be easier to provide an outboard alternative as well as the inboard - that will be made separately and retro fitted to inboard boats.
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Originally Posted by Zippy
When a boat looks that good who needs tubes!!!
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Old 25 March 2010, 07:15   #86
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Here are some more updates for you guys and girls .........

The location points on the flange (last photo) are half ping pong balls glued on, start the mould next!
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Originally Posted by Zippy
When a boat looks that good who needs tubes!!!
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Old 25 March 2010, 08:11   #87
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Coming along nicely Cookee

Quote:
Originally Posted by Cookee View Post
The location points on the flange (last photo) are half ping pong balls glued on, start the mould next!
You didn't buy a load of those mould clamps off lloyde then?

http://www.henleycraft.co.uk/GRP%20M...e%20Method.htm
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Old 25 March 2010, 08:17   #88
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Quote:
Originally Posted by Downhilldai View Post
Coming along nicely Cookee



You didn't buy a load of those mould clamps off lloyde then?

http://www.henleycraft.co.uk/GRP%20M...e%20Method.htm
I think I have a freebee comming in the post, but I aint holding my breath
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Old 25 March 2010, 08:19   #89
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Quote:
Originally Posted by kitten View Post
I think I have a freebee comming in the post, but I aint holding my breath
Will one be enough?
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Old 25 March 2010, 09:53   #90
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Quote:
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Will one be enough?
Well he says they are really good. Anyway, what you bin doin on the dark side?
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