Wakeboarding A-Frame

King_C · 23 April 2009, 12:55

Hey guys.

I wasnt quite sure what section this should go in so here it is...

Im looking at buying/building an a-frame on my Avon Adventure 560 that I can wakeboard off and I have a few questions.

1/ Does anybody know of manufacturers that build an a-frame strong enough to deal with the forces involved in wakeboarding?

2/ Does anybody know someone who has built their own frame for wakeboarding?

Any other tips?

Thanks.
Charlie

Nasher · 23 April 2009, 15:29

Hi.

The issue isn't the frame being strong enough, its how it's attached to the boat that needs to be strong enough or engineered correctly.

Most RIB A-frames do not have a mounting point forward enough on the boat, and end up being a big lever acting on the transom if a force is applied at the top. They will tear off the boat as a complete unit before being broken themselves.

I've thought about a webbing strap attached to the top of the frame and being brought forward to a strong point in the bow, but have not taken it any further as I think it will still stress the mounts too much.

Nasher.

JSP · 23 April 2009, 17:34

Wouldn't a post be better ? Still the issue of how to anchor but if your up to loosing deck space for it, it could have legs coming off to act as a brace.

Heart-trouble · 23 April 2009, 17:55

why dont you just use a bridle between the two d-rings on the transom and tow off that?

Nasher · 23 April 2009, 20:15

Quote:

Originally Posted by Heart-trouble

why dont you just use a bridle between the two d-rings on the transom and tow off that?

Because the 'upwards pull' from above helps.

Nasher

King_C · 23 April 2009, 21:16

Quote:

Originally Posted by Heart-trouble

why dont you just use a bridle between the two d-rings on the transom and tow off that?

Yea as Nasher said, and upward pull is important. Its almost impossible to get air with towing on the D rings.

As for the issue with the force applied to the mountings, I see your point. I had thought about this. Wakeboard towers are usually only mounted at 4 points in the deck although I do wonder if the fiberglass is stronger in the topdeck of hard boats than the deck of a rib?

I thought perhaps have 4 mounting points, 2 as rear as possible (possibly also bolted to transom as i assume that is stronger than the deck?), then 2 as far forward as possible without intruding in the passenger space. Then I figured having a plate bolted in several places along the deck between the rear and front mountings with the frame welded/bolted onto that would spread the pressure out more?

http://www.onlyinboards.com/ski-boat...boss-swoop.jpg
This style frame would allow the mountings to be spread further whilst keeping the actual frame behind all the seating.

Thanks.

Kernow Buoy · 23 April 2009, 21:49

Ribtec do (or did) a strong A frame but it's an original not aftermarket option that fixes down through the deck AND the hull,
Ribcraft do a strongly built one too, Roycruse had one which he wakeboarded behind with no problems.
He was 20 stone at the time!
I've got a custom built frame with a forward leg fixed to the deck, I'll get a pic tomorrow.

Heart-trouble · 23 April 2009, 21:49

i see, not done much wakeboarding, no demand for it on the upper clyde, unless you dont mind a wee bit of sewage!

King_C · 23 April 2009, 22:57

Haha a bit of sewage is good for the soul! Altho maybe not the heart hey "heart-trouble"?

Cheers Kernow a pic would be wicked!

Ill definately have a word with ribtec and ribcraft to see what they say. Ive seen Avons with them before, I think outhill made them, but these frames seem to have disappeared off the face of the earth

PeterM · 24 April 2009, 10:57

I 'think' the newer Shearwaters also have a frame you can tow from ? Jim Robinson on here can confirm details of how they acheive it. I may have read it on thier website ?

Yep - is on this page ...

http://www.shearwaterribs.com/content/features.php

Nasher · 24 April 2009, 12:20

Quote:

Originally Posted by Blackroady

I 'think' the newer Shearwaters also have a frame you can tow from ? Jim Robinson on here can confirm details of how they acheive it. I may have read it on thier website ?

Yep - is on this page ...

http://www.shearwaterribs.com/content/features.php

"The towing eye in the top of the frame will pull a reasonable size skier"

Don't like that word - Reasonable - in a context such as that.
Sorry Jim, but it means bugger all.
Am I a reasonable size at 15st?

Nasher.

Kernow Buoy · 24 April 2009, 14:20

Here you go Charlie, can't tell you who made it but might give you some ideas.

Chris · 24 April 2009, 14:56

Hi Speak to Mark at Marine fabrications 01543 670033

He did a great job on my Aframe and they regularly build bespoke A-frames for wakeboarders.

King_C · 30 April 2009, 22:39

Yea I dont like the sound of a "reasonable size skier" either. Especially since wakeboarding exerts a larger force than most peoples "recreational" skiing.

Cheers guys I'll look into all these ideas and I'll let you know how i get on.