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rudder hardware

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rudder hardware

Postby doclees » Tue Aug 05, 2014 6:40 pm

I have been given a Grampion MK II. I need to make rudder, centerboard, thwart and centerboard trunk top. Anyone have specs they can share? What material is the rudder hardware made out of. Thanks.
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Re: rudder hardware

Postby dgmarsh » Wed Aug 06, 2014 11:52 am

The class rules should have what you need:

http://albacore.org/iaa_files/rules/IAA ... 2014_a.pdf
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Re: rudder hardware

Postby townsend » Wed Aug 06, 2014 12:09 pm

Rudders and centerboards are typically made out of wood, although there are many that are made out of other material such as vinylester resin over structural foam. If you are doing it yourself, wood will be the easiest.

The class association rules have detailed dimensions for the centerboard - you'll need to follow those closely if you plan to race in events above the local club level. The centerboard handle is not constrained by the class rules and you may need a different shape there depending on the geometry of your centerboard trunk.

The rudder itself is not constrained by class rules, and there's a wide variety of rudder shapes that are successful. Hopefully you still have the rudder head and tiller assembly. If not, APS sells rudder heads and the hardware to mount them, although they are not cheap. (http://www.apsltd.com/c-107-pintlesgudg ... heads.aspx ) You could probably fabricate something yourself if you are handy in the shop. I think you need a curved tiller to fit through the hole in the transom of a Grampian.

I wouldn't obsess too much over getting the perfect shape and sized rudder, especially if you are not planning to race. A basic rectangular shape with an airfoil section will work fine. Make sure it goes fully vertical. I'll measure mine tonight and give you the dimensions.

Here's a site that will give you an idea of what a good rudder looks like: http://www.fastcomposites.ca/site/marin ... /albacore/ I'm assuming you are planning to build it yourself, but you can buy one already made.

You also might want to check this thread form a few years ago:
http://usaa.albacore.org/forum/viewtopic.php?f=1&t=873
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Re: rudder hardware

Postby townsend » Thu Aug 07, 2014 3:13 pm

I took a tape measure to a couple of rudders after racing last night.

My rudder is a Phil's Foils high aspect rudder, and it measures 75 x 20 cm, where the vertical height is the amount of foil below the water line. It's about 100cm if you include the top part that pivots inside the head.

Another Albacore on site had a rudder 72 x 20 cm - this is an old Toronto community sailing club boat, and I think the rudder was hand-made. It's not the standard OY blade.

I also measured a Vanguard 15, and it was more low-aspect at 60 X 24 cm. A Hobie 16 rudder was 70x24 cm.

Since you can regularly find H16 rudders on ebay for about $50-75 (what is someone with only one going to do with it?) this might be a good inexpensive way to get a blade without having to fabricate it. I'm fairly sure one would work just fine on an Albacore for anything other than top-level racing.
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Re: rudder hardware

Postby gjxj » Tue Aug 12, 2014 1:53 pm

this reminds me.. how do you obtain a suitable piece of wood
for fabricating a centerboard?
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Re: rudder hardware

Postby townsend » Tue Aug 12, 2014 3:57 pm

gjxj wrote:this reminds me.. how do you obtain a suitable piece of wood
for fabricating a centerboard?


https://www.jamestowndistributors.com/u ... 00_448.pdf

suggests western red cedar or redwood. My centerboard is the original mahogany from the late 70s and is still going strong. My rudder is made out of Sitka spruce.

The article explains why plywood is not a good choice.
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Re: rudder hardware

Postby henry » Wed Aug 13, 2014 9:22 pm

That is a pretty good article. I like that it instructs you to rip your work into strips and turn each alternating one 180 degrees and laminate the strips all back together. It makes for a stronger blade that resists warping. Sitka spruce has one of the best strength to weight ratio of wood types, with Western Red Cedar also up there. There are also hundreds of blades made of mahogany, both solid and laminated. It's heavier, but tough.

There's a lot of work involved in making your own blade like that.

There's a company in Ottawa, Competition Composites http://www.fastcomposites.ca/site/ that uses a cnc mill to make plugs for their foil shapes. They used to be able to mill out a perfect aerofoil shape out of a block of wood and sell it to you in that rough state so that you could finish it yourself. They may still do that. Might be worth a call.
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Re: rudder hardware

Postby doclees » Wed Aug 13, 2014 9:29 pm

Thanks folks, I was painfully up on long island sound without a boat. Such perfect sailing weather. But now I can get back to work on this. I'll try again but I think I need a paid membership to get to that section of the forum.
I was thinking about a rudder from a beach cat. Yes you do see singles often for cheap. Do they mount in a similar way on the transom? This sure would save a lot of work.
Anyone have good pics of the centerboard cap and thwart? Don't have those either but making should be easy.
How about stern anchor point for hiking straps? Yep no straps either. Oh but I do have a mast....which I don't need because I'm junk rigging. So much for racing. I think that would be a deal breaker.
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Re: rudder hardware

Postby 7959 » Thu Aug 14, 2014 9:47 am

Junk rig? that's interesting. do you have a diagram of what you want to do?
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Re: rudder hardware

Postby townsend » Thu Aug 14, 2014 10:40 am

doclees wrote:I was thinking about a rudder from a beach cat. Yes you do see singles often for cheap. Do they mount in a similar way on the transom? This sure would save a lot of work.


Yes, they would mount in exactly the same way. I think the main issue is that H16 blades are 25mm thick and most monohull rudder hears are 20mm. At least that's what I discovered the last time I tried putting a cat blade on one of the club monohulls - the blade was too thick to fit in any or our monohull rudder heads.

That said, you can probably find or fabricate a head that will fit a H16 blade.
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Re: rudder hardware

Postby doclees » Fri Aug 15, 2014 9:57 am

7959 wrote:Junk rig? that's interesting. do you have a diagram of what you want to do?


As a member of the Junk Rig Association I plan on using a very successful cambered paneled sail and later swap it with an emerging Aerojunk design.

Rudder Head! Thanks, was blanking out on the term. Anyone have pics on the rudder head assembly? I can make the rudder OK and even the rudder head if I know its materials and dimensions.
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Re: rudder hardware

Postby gjxj » Fri Aug 15, 2014 10:58 am

"The article explains why plywood is not a good choice."

I'm sure its not the best, but my original plywood centerboard lasted ~30 years. (finally snapped it righting the boat)
I'm currently running a board i made from box store plywood ("weather resitant" ), completely encased in fiberglass.
I figure I'm on borrowed time and looking to make a more permanent one if/when this one warps on me.
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