Rudder blade question

[Mike Pennington]

I am building a new rudder and I came up with a question that I should know the answer by now. BUT?

The Vacationer plans call for a 3/4 inch thick blade x12, however I am wondering if I can mill down a 2x12 narrowing the edges, leaving the center thick. It seems to me Robert Cox made a thicker blade and I was wondering if it would hinder or help?

So what do the more experienced have to say?

Mike

[Frank Hagan]

You'll have to try it and see ... but I doubt that it will have any kind of performance penalty that you'll actually notice during sailing.

The NCAA foil guys (if I have that right) always have a formula for the thickness, width, etc. of these things.

[Barry Pyeatt]

I made a new rudder for my Weekender. The discussion and photos are a part of this string. http://www.messing-about.com/forum/viewtopic.php?t=3061&highlight=rudder

I don't know what the actual performance results will be until I get some time using it and comparing it to the stock design. But the general concensus is that it should be more effective at slower speeds. At higher speeds it may not make any difference. The slower speed performance is what I'm primarily interested in.

[Mike Pennington]

Thanks Barry, and Frank,

I wasn't really looking so much for performance improvement as strong and not break.

The spine seems to be the weak spot in my past rudder. I want to go to a thicKer spine, but the 3/4 blade would then be flopping around, I supose I could shim the upper portion of the blade, but then I remebered the linked post about the foil shaped rudder.

I bought some 3/4 inch birch ply for the rudder box and I am going to try foil shaping a 2x12. The one difference I am going to do is keep the thickness at the swivel point in the mast box. All the added sail area has definitely been felt by my old rudder So I wanted to build a Super Rudder that would be harder to break.

Performance wise, I think not using the rudder as a break and the right mast angle are more important to keep from stalling out.

Thanks for the link Barry it was good reading a well written explanation of how the rudder works.

In reading, leaving the bottom portion of the rudder flat and not tappered is the way to go?

I'll post a picture or two as I go.

Mike

[Tim Diebert]

Build one like this Mike. Lots of solid wood. Very strong.

8)

Actually, it sounds like you are on the right track by going heavier with all your bits and pieces. It also sounds like you are a maniac sailor ...anybody busting up rudders like that. Good show. :thumbsup:

[Charlie Jones]

Last year I built an emercency rudder (in an afternoon) for a Mac 25 using a 2 by 12 and tapering it just by eye. They liked it so well they glassed it and are still using it.

[Tim Diebert]

How do you mean 'an emergency' rudder Charlie?

They would replace the broken one with what you made, in the same location? Or a whole separate system? Just curious.

[Mike Pennington]

Hi Charlie,

I was thinking of you a week ago. You once made a post, titled never enough clamps, I believe. Showed a pic with clamps every where 8)

I built four clamps that had an eight foot reach when I welded my trailer together.

Tim, I use to have a tiller for the Vacationer but went to the wheel. I figure their is not enough room in the cockpit for me and a tiller both.

Although, I am copying that pick for reference later, in case I need a pattern to work from for another boat. That is a very fine looking rudder and I don't doubt that it is strong.

Mike

[kydocfrog]

Tim; awesome...

DocA

[Tim Diebert]

Thanks Doc.

Looks much nicer now that it is varnished and the transom is basically all done.

My crew is giving me the, "Quite finding more projects to do and just get this thing in the water....I wanna go sailing!".

[Konrad in Lincoln]

Yeah, I've built more than one rudder for my Vacationer. Not because I'm a sailing maniac, but because I've forgotten to raise the friggin' rudder when I pull the boat out of the water, and then I put it in reverse up on land and... Crack! Splinter...

Damn, damn, DAMN... :evil:

[Mike Pennington]

Maybe I should invent an auto retractable rudder. Kind of like the the tollet bowl float, no water- and bong up it goes

Konrad, I've done that one too.

Ray, out of babe's mouths :wink: