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Old 22 November 2008, 23:32   #1
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Avon Searider 5.4 A Frame

Hello,
I just recently picked up an older SR5.4. I am stepping up from my SR4. I am just beginning to build an A Frame for it. I am planning on fabricating it out of stainless steel tubing. I was planning on 1.5in diameter (31.8mm) tubing. I considered 2in, (50.8mm) it seems a little big, but I am still open to it.
What size wall thickness is common for A Frames? Any suggestions on diameter?
If anyone has some pictures or drawing of other A frames, that would be appreciated. I have searched the site and google so I have a few. I have made some sketches which I can post later for comment. Thanks for the help.
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Old 23 November 2008, 05:27   #2
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Depends on how you design it and what you want from it.

For a single hoop, provided it's not too tall, you should be ok with 1.5", but personally, I'd go for 2", with 1.6mm or 2.0 mm wall. The problem with 2", is that less people are able to bend the tubing, whereas 1.5" tends to be no problem. You can buy pre-formed bends and weld these to straight tube sections if this is a problem. Don't even think about towing off a single hoop A-frame.

For a twin hoop design, 1.5" OD, 1.6mm wall would be fine, but if you want to tow a skier/wakeboarder off it, then, you'll need 2"OD, 2mm wall, with the forward hoop fixed to the deck/hull.

Would be good to see your sketches.
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Old 23 November 2008, 20:59   #3
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I think I will go with the 2", that was my original plan but after seeing it thought it was a little large. I do not plan on having any bends, only welded corners, might not look quite as elegant, but it should still look good. I am planning on doing double hoops that come together to a single, larger pipe at the top. I am going to replace the original transom braces with a new angled tube. I will try to fire up my scanner and get my drawing in.
I dont plan on pulling skiers much, but I am sure it will happen so I want to build for it.
Are most made out of stainless steel or painted carbon steel? I have been planning on stainless due to the corrosion resistance, but is harder to weld and more expensive. Thanks for the help.
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Old 24 November 2008, 02:47   #4
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2 inch will look nice and I'd go with stainless or I think Seariders can look really good with them powder coated the same colour as the hull.
I got a great offer from a friend of a friend who had a big job on with stainless tubing, he offered to make me one and add it on to the bigger job. Went down there with measurements and to chat with him to find what looked like stainless scaffolding bars
Would have looked like I'd fitted a little searider to a big A frame.

Good luck with it
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Old 24 November 2008, 15:43   #5
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Here is the quick sketch I made. At the time I hadn't measured the transom and mounting points so I just approximated. All of the lengths are approximations. I will probably break out Autocad to get the angles and lengths correct.

I have decided to use the 2" tubing with a 3"-4" tube on top. I made the design to avoid bends. For the front support, I was not sure whether to make it go up and then angled back or just strait up to the top with no bend. As of now I am going with the up, then back. I want to make it as tall as I can and still fit in the garage.

I am picking up the pipe this Thursday. It is surplus from an out of business factory. Any comments are appreciated, I am open to design change.
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Old 24 November 2008, 15:54   #6
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I can't see what you're gaining from having a bend in the forward tube

Personal taste, but I think the 2 different size tubes looks clumsy and top-heavy. I would use 4 no. 90deg bends and have the same dia tube throughout, even if that means having the two horizontals close to each other. Joining plates on the top would give you a neat flat surface to mount aerials, lights, cameras, etc.
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