Designing to Steve Clark's proposed new rules

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jimc
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Post by jimc » Thu Dec 01, 2005 9:14 pm

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Steve Clark</i>
The rudder foil seems like a very cool deal, but I'm not sure that a 5000mm boat needs one if the waterlines and areas are balanced.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

I'm thinking more on the lines of being able to bang the seat right aft all the time in a reasonable breeze and use the T foil to lift the stern to get the trim back upwind. I just wish I could persuade myself that doing so wouldn't be too much drag in the light stuff, 'cause then I could ditch the seat carriage.

Phil Stevenson
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Post by Phil Stevenson » Thu Dec 01, 2005 9:30 pm

I do not think a rudder foil will be needed.

Looking at A Cats they do not have a longitudinal stability problem and the canoe is only a little shorter and with a lot shorter rig and less power.

Back in the 1960s when we were first designing A Cats we just kept moving the rig back and making the bow finer, and boats stopped tripping over themselves. A fine bow goes through waves and does not trip the boat, blunt bow cats and moths are real pigs. But to go through rather than over waves you need volume from more depth, (or in A's, they use more length)

If anyone wants to build a full size version of my model please ask and I will send the rough dimensions of the ply cut out and spread widths once I copy them onto a spreadsheet.

Hopefully these boats will go fast enough to reach off and avoid the square run wobbles. But the satbility of the narrow canoe (as measued by the moment of inertia of the waterline plane) is 7 times more stable than that of a modern narrow moth, and we always run as square as we can because it is still faster for us in Archimedian mode.

Incidently about 1969 we saw Bob Miller (= Ben Lexan) and Carl Ryves testing the first prototype Contender in Sydney Harbour. Although it had a transom and trapeze it was very similar in dimensions and power of the proposed canoe. It was only about 750 wide, light weight, hard chine with heavilly raked fully battened sail rigged well aft. We have some super 8 movie of it going very fast against some A Cats. It was a pity it scared the IYRU who sent them home to euopeanize the design and create the old fashioned looking Contender we have now.
Design perfection is achieved, not when there is nothing else to add but when there is nothing else which can be taken away.
http://philscanoes.blogspot.com/

Phil Stevenson
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Post by Phil Stevenson » Sat Dec 03, 2005 9:38 pm

I have prepared a spreadsheet of offsets for the stressed ply canoe design as shown on the Aust Canoe site. For any experienced builder there is enough to build one. If anyone wants a copy please email me:
philstevo2003@yahoo.com.au
Sorry I do not seem to be able to post attachments here.
Design perfection is achieved, not when there is nothing else to add but when there is nothing else which can be taken away.
http://philscanoes.blogspot.com/

jimc
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Post by jimc » Sat Dec 03, 2005 9:44 pm

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Phil Stevenson</i>It was a pity it scared the IYRU who sent them home to euopeanize the design and create the old fashioned looking Contender we have now. <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

And just think, if they hadn't done that the world probably wouldn't have got the Laser and the sailing world would look very different:-)

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Christian AUS
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Post by Christian AUS » Sun Dec 04, 2005 9:50 pm

Phil Stevenson has the plans for his Canoe online at http://www.internationalcanoe.yachting. ... F13267%2F0

Andy P
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Post by Andy P » Wed Dec 07, 2005 9:29 pm

I've now sailed my old IC a couple of times. In 10-15knots it was fun!
Upwind very nice if a little sploshy bow waves - the new designs should eliminate this. Reaching was fast, and surprisingly stable fore and aft.
However in 4-5 knots it wasn't so much fun. OK upwind, but I can now see why you guys want to make it more exciting and faster downwind. ( because it was slow ). Dead running and goosewinging the jib, sailing slower than lasers on the same heading but opposite gybe. Trying for more speed at asymmetric reaching angle was faster through the water, but still slower than laser to the mark.
But much more stable than a moth.

The wetted area must be huge, and only low power rig.
The new design will have much less wetted surface, and with single sail will have more power in this light stuff. ( and easier with no jib to trim )

Reducing weight and carbon mast will also make the boats feel more lively - but still much more stable than a moth.

Andy

Steve Clark
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Post by Steve Clark » Wed Dec 07, 2005 9:58 pm

Should be able to out run a Laser, even in light air, but not by enough.
Having the leeward shroud go away is huge, but until the additional length can start doing you some good, you go downwind as fast as anything with 10.6m^2 of sail.
Glad you enjoy the ride as the breeze comes up, the harder it blows the faster it goes.
SHC
Beatings will continue until morale improves

Andy P
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Post by Andy P » Tue Dec 27, 2005 10:52 pm

I agree with Steve that the static calcs don't mean much - as soon as you start moving, the wave making effects take over that are not in the calcs.
I find that the prismatic is an end product of the design ,and not a target.
Wetted surface calcs can be helpful for light weather performance, but there is so much more ....

Johan's rig problems must relate to a very stiff mast and full sails - I feel that flexy rigs and flatter sails will be more suitable for the lower drag new IC.

The comparison between my last moth and latest IC design show how BIG the IC is, and gives some idea of relative stability ( in both planes )

Image

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Christian AUS
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Post by Christian AUS » Fri Dec 30, 2005 11:25 pm

Hi Everyone,
Happy New Year as we celebrate it, and I hope we are ringing in the New Year together in Australia in 2 years time.

I've added some new/updated designs from Rob Mincher and Andy to the ICAA websie http://www.internationalcanoe.yachting. ... ms/13163/0

I've been spending a lot of time reading back through all the IC history stuff, and it's funny how all these design change proposals have been done before. Skinnier hulls, two masts to single masts, planks, Nethercott hulls....... It will be interesting to see if 2006 is a year of major change in IC history. If nothing else, I hope that we can maintain and build on the input and drive from so many talented sailors/designers and translate that to more boats on the water (be they AC, IC or something we haven't considered yet).

Have a safe and happy New Year and may the best results of 2005 be the worst of 2006.

Christian

Phil Stevenson
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Post by Phil Stevenson » Sun May 28, 2006 11:54 pm

I have started construction of my stressed ply DC using 3mm Ukoume/gabbo. I will post some photos when I figure out how to add them to this forum.
Design perfection is achieved, not when there is nothing else to add but when there is nothing else which can be taken away.
http://philscanoes.blogspot.com/

Phil Stevenson
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Post by Phil Stevenson » Tue May 30, 2006 8:33 am

Here are the photos of first stages of construction:
Ply sheets:
Image
spread for internal seams: Bow open to get rounder sections.
Image
Image
Design perfection is achieved, not when there is nothing else to add but when there is nothing else which can be taken away.
http://philscanoes.blogspot.com/

Phil Stevenson
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Location: Australia

Post by Phil Stevenson » Wed May 31, 2006 10:34 am

Design perfection is achieved, not when there is nothing else to add but when there is nothing else which can be taken away.
http://philscanoes.blogspot.com/

Karl Wittnebel
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Post by Karl Wittnebel » Thu Jun 01, 2006 9:32 am

Looks great, Phil! Inspiring to say the least.

You may wish to get the Cg lower on the aft deck (i.e. lower the deck a bit), as I don't think you'll be sinking as much as on the Moth, and it would seem more stable in the corners.

Keep posting!

Karl
Karl Wittnebel
NC USA 193 (Lust Puppet)

Phil Stevenson
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Post by Phil Stevenson » Thu Jun 01, 2006 9:54 am

Karl,
The boat is about the minimum allowed 300 deep amidships, and about 250 deep aft. The cockpit will be dished, probably more than normal for an IC, which should help get my CoG lower. I was not concerned about depth aft but was wondering if I had made it too high up front. Then I look at IC photos with water up to the boom and think I am right. Bow height is 450 - the same as a moth.
Today I completed the seams outside and tomorrow I will put a carbon skin inside from mast to seat, and begin bulkheads and fit out.
Mast and boom are made, I have a rudder and centreboatd but may need a bigger one. Alloy tubes for seat went to bender today.
I have another week holiday to make major progress.
Design perfection is achieved, not when there is nothing else to add but when there is nothing else which can be taken away.
http://philscanoes.blogspot.com/

Paul Scott
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Post by Paul Scott » Thu Jun 01, 2006 2:38 pm

Phil-

Nice looking hull!
"Exuberance is better than good taste" -Flaubert

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