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PostPosted: Mon Feb 07, 2005 1:42 pm 
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Joined: Wed Jun 30, 2004 6:39 am
Posts: 471
Location: Finger Lakes, NY
Hey Matt and others, I wanted to get back to discussing rudders, specifically home made rudders, pardon the new thread please 8)

Part One: There were mentions of homemade wooden rudders on the un-fared rudder thread. Could you let us know what makes them class legal or not and if there are any plans or preferred construction techniques. Is solid wood like mahogany or oak or is plywood better and what kind of ply; Marine or cabinet-grade birch or other? I think a ply and clear resin rudder would be beautiful!

Part Two: I have access to Kevlar, resin and Carbon fiber materials and techniques. Am I breaking any patent laws if I make a mold of my old EPO's and build my own set of hi-tech rudders? Can I use them in races? Can I sell them if I build them. How about Lexan?

Part Three: Any modifications allowed to the rudder dimensions like changing the chord or root measure allowed or does that throw them out of class too?

It is a long winter :roll: peace out

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The fact that this windy world is largely covered in water obviously means that man was meant to sail.


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PostPosted: Mon Feb 07, 2005 3:02 pm 
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Joined: Mon Oct 11, 2004 12:24 am
Posts: 143
Location: Edmond Oklahoma
Stephen, I would say you have the go ahead Looking at the 2005 IHCA page 15 para 1 sub 1.1, 1.2 as long as you stay with in design and measurments: Matt Bounds would know more.

G-day

Todd


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PostPosted: Mon Feb 07, 2005 3:25 pm 
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Joined: Thu Mar 25, 2004 5:39 pm
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Location: West Texas
I *hope* the foam core one my friend and I made is class legal. :oops:

6 layers of glass, plus oak at the top to strengthen it where it links to the tiller. :)

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Jim

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 Post subject: Rudders are open...
PostPosted: Mon Feb 07, 2005 5:34 pm 
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Joined: Tue May 27, 2003 12:44 pm
Posts: 9329
Location: Oceanside, California
Rudders are open for the 14 and 16. There are weight and shape rules in the rules book.

http://www.hobieclass.com/site/hobie/ihca/downloads/classrules/RBook050401_1.pdf

1. RUDDERS AND RUDDER ASSEMBLIES
1.1 Rudder blades made of another material yet
conforming with the size, shape and minimum
weight of the standard rudder blades may be
used. Rudder blades must conform within the
minimum and maximum dimensions that are
found within the profile plans. Profile plans are
available through the IHCA.
1.2 The maximum thickness of a rudder blade(s)
shall not exceed 1.015 in. (25.8 mm.), tapering
over a distance of 2 ft. (60.96 cm) to a maximum
thickness of 1/2 in. (12.7 mm), 2 in. (50.8
mm) from the bottom tip of the rudder. These
dimensions are for reference purposes only.
Please refer to profile plans for exact dimensions.
Profile plans are available through the
IHCA.

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Hobie Cat USA


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PostPosted: Mon Feb 07, 2005 9:08 pm 
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Location: Edmond Oklahoma
Jim your safe as long as it makes weigh in and measurements looking at your site you should be fine.

Stephen Sorry I just remembered you have a 17, your just a 16 guy at heart. e-mail me maby we can work something out on a set for my 16.

Todd

Every Picture tells a story. :P


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 Post subject: Home-made rudders
PostPosted: Tue Feb 08, 2005 6:31 am 
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Joined: Mon Jul 14, 2003 7:11 pm
Posts: 4643
Location: Detroit, MI
Oh, boy - where to start?

If you are really into a project, then you can make your own rudders for your 14 or 16. Jim did a neat job on his, and it seems to have held up well. Check out his thread / website (Jim, can you post the link, I can't find it right now) for his construction techniques.

I've seen some of the Brazilian wooden rudders and they are works of art. They laminate 1"x1"x3' strips of various woods (I don't know the species) to create a blank, cut the profile, then shape the foil. They require a lot of maintenance and special handling.

The toughest part of any rudder project is shaping the foil. The maximum allowed thickness (just over 1") produces a foil that is thinner than you would want for optimal performance. (If you are into learning about foils, "Theory of Wing Sections" by Abbot and Von Doenhoff is a classic reference.) Minor imperfections can cause major ventilation and cavitation problems at high speeds.

There are places that will produce CNC foam blanks (Phil's Foils - http://www.philsfoils.com/) if you want to go the carbon/fiberglass route.

The bottom line is you should build your own rudders only if you have the time (extensive) and skills (considerable) and want to be able to show off your handiwork. Otherwise, plunk down $500 bucks and snag a couple of those sexy looking rudders in the previous thread.


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PostPosted: Tue Feb 08, 2005 7:49 am 
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Joined: Thu Mar 25, 2004 5:39 pm
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Location: West Texas
You can just click the little "WWW" button at the bottom of any of my posts to go to my site. :)


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