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PostPosted: Fri Aug 23, 2013 12:41 am 
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Location: Melbourne, Australia
When out on my A.I. I've noticed that there seems to be a fair bit of free-play between the AKA crossbars and
the section of the AKA knuckle-joint that slots into the crossbars.

I haven't actually measured it, but it would be a couple of mm at the joint, which seems to translate to a few cms
at the AMAS.

Is this usual?

Mike.


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PostPosted: Fri Aug 23, 2013 2:27 am 
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Location: Forster, NSW, Australia
I think it is normal.


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PostPosted: Fri Aug 23, 2013 2:40 am 
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I sort of get the feeling mingle that this is something that shouldn't be talked about. It always gets met with silence. Nobody knows what is normal, and what is 'out of spec'. 1mm of movement at the knuckle, amounts to a fair wack out at the Amas. So this thread seems like a pretty good place to start and set some sort of standard.

If we use mine as a benchmark mainly because my Akas are brand new. The crossbars are 2 years old so it would be good if someone out there, who has a newer Island, could measure theirs.

Total vertical movement of the Akas sticking out perpendicular to the hull, I get this at the front..........

Image

...........and almost identical at the rear.

Image

I'm only guessing that this is normal and certainly doesn't feel excessive. What's yours ?

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PostPosted: Fri Aug 23, 2013 3:24 am 
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That's interesting, slaughter... When I'm able to get to my yak, I'll do the same.

I find it most noticeable when moving slowly and in choppy conditions when the
joints 'clunk' and wobble like an OAP's dentures...

After experience with both the old an new AKA joints, I think the older ones are
a much more satisfactory design - far simpler, with two less potential points of
failure.

Mike.


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PostPosted: Fri Aug 23, 2013 8:57 am 
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Location: Riverside, S. California, USA
I am on my second set of akas on my 2010 TI (mine since 2012). The first set had almost no play, the current set has much more (maybe 1 mm at the joint). It turned out the no play was not a good thing, though.
Unbeknownst to me, there had been galvanic corrosion between the stainless hinge pin and the aluminum knuckle casting, enough the seize the pin. In its first life, the boat lived at a saltwater marina in San Diego, and judging by it condition when I bought it, spent almost all of its time on shore, amas folded, under a tarp cover.
After the pin seized, the amas could only have been opened by breaking either the seizure, or the screw holding the pin stationary with respect to plastic knuckle end cap, and thus to the aka. What let go was the screw. In a new joint, removing this screw allows the pin to fall out of the knuckle, but with the pin seized to the aluminum, it stayed put, and there was essentially no play in the joint, and I was none the wiser.
However, then I took the boat on a wilderness trip on the Colorado River. Probably due just to Murphy forces in such a setting (their strength is proportional to the square of the distance from help), but maybe due extreme temperature differences between the water (52°F, 11°C) and the air (110°F, 43°C), one of the pins came free of its seizure and fell out while we were tacking in pretty gnarly conditions (narrow canyon, strong but variable wind, significant current). :o
When I got back, I looked inside all of the knuckles, and every one of the screws was sheared off.
Anyway, I now have new akas (Hobie was GREAT), and they have much more play, I think probably more than my originals ever had, probably a bit less than 1 mm at the knuckle, so the corrosion problem is unlikely to repeat (especially because now I am watching, lubricating, washing that, so Murphy can take advantage of my distraction to work somewhere else).
I like the new hinge design, but I agree that the older hinge (I have a 2008 AI) is simpler and would not have had or hidden this problem. I have also had the aka slip out of its socket unexpectedly, which the old design could not do.


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PostPosted: Fri Aug 23, 2013 11:04 am 
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Location: High Point, NC
Mine certainly have some play, whether or not it is a problem I'm not sure. Other than a little noise and a little movement, there doesn't seem to be any difficulty created.


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PostPosted: Fri Aug 23, 2013 12:48 pm 
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Absolutely normal.

Islands are not precision beasts. These are roto molded products which do not have tight finished dimensions. Different material colors and thicknesses shrink at varying rates. They all vary a bit.

The geometry that allows folding amas is problematic due to some of the variances. Connecting parts were designed with tolerances and production tolerance in mind.

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PostPosted: Fri Aug 23, 2013 2:26 pm 
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Location: Lexington, NC
I don't know if Hobie would recommend it, but I did this last year, and have had no problems.

viewtopic.php?f=69&t=45381


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PostPosted: Sat Aug 24, 2013 3:53 am 
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It's funny mingle, I posted the very same question back in 2009. I finished up making the following mod which quietened down the clunk at the joint substantially. viewtopic.php?f=75&t=13167&p=73840&hilit=aka#p73840

But that was the original design. Personally, I think the new design is superior and a worthy improvement.

I don't transport the AI with the Akas and Amas attached. For the minimal time it takes, I think it's worthwhile to disassemble and assemble, in thinking that the possibility of it bouncing around on the trailer can't be good for the joint. This is my trailer arrangement for what it's worth.

Image

Just a thought.

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PostPosted: Sat Aug 24, 2013 6:10 am 
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I thought about disconnecting the amas on my TI when on the trailer, but they seem to sit well on the cradles with no stress on the akas on this model.


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PostPosted: Mon Oct 07, 2013 8:49 pm 
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viewtopic.php?f=78&t=44761&start=15

On page 2, I posted pics of my trailer. I made a special cradle system that supports my ama, aka, assembled AI without any stress to the aka joints. The hull is elevated to the right hight to allow the amas to rest in their natural folded position A roller was also added to make loading and unloading smoother.


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PostPosted: Wed Oct 09, 2013 8:16 pm 
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Location: Melbourne, Australia
I measured mine and there's about 25-35mm of free-play (up/down) at full extension, so I guess it's pretty normal.

I only attach the AMAS before I wheel the yak to the beach - about a 450m walk.

I transport the A.I. on my car (a small hatchback) - hull on the roof, AMAS and everything else squeezed inside.

Mike.


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