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PostPosted: Mon May 14, 2012 5:41 am 
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Joined: Fri Jun 05, 2009 7:44 am
Posts: 65
Location: Philadelphia, PA
Thank you, Nohuhu, for mentioning the longevity issue. I forgot it in what was already a long post. Loose joints typically only get looser. And rivets walk. If nothing else, I'll solve that at the end of this season with epoxy, I guess. Only drawback would be having to replace both aka and the pin joint (don't know the part name) if either got damaged.

What kind of sea conditions are you typically in? If the period of the waves is longer, there's far less side to side rocking, and it comes through slower. Good wind for me means heading to a lake or Barnegat bay. No fetch for longer waves to build up. So it's choppy. Many more, and more violent side to side pitches in such conditions.


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PostPosted: Mon May 14, 2012 8:39 am 
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Location: Philadelphia, PA
If you are interested in this thread, please look at

viewtopic.php?f=71&t=42667
LOOSE RIVETS ON AKA KNUCKLE ASSEMBLY
started by Yakaholic

The reports there confirm the concerns expressed by Nohuhu and myself about how these loose xbar to aka joints would wear over time. The rivets go first it seems.

Think about it. These joints have to do two things. One, stop the aka/ama assemblies from moving up and down relative to the long axis of the boat. That is keep the floats rigidly extended. The other is more subtle, but probably the source of much of the wear and tear problems. Drag on the ama's wants to move them backwards and thus ROTATE the aka pipe in its socket. So this puts sheer stress on the rivets (or any screws). Looseness creates a ton of repeated impacts on the rivets--perfect for deforming them.

The same thing goes on with the aka assembly insert where it fits into the xbar. It not only has to stop up and down motion, but it has to resist rotation. Rotation wants to happen to it not only when sailing, but what we fold the ama/aka assemblies in. The whole thing wants to sag down, because the inserts into the xbar are held only by spring clips. This brings us to the problem talked about in
another thread (can't find it now), where the inserts become very hard to remove, because they have twisted and now remain somewhat twisted.

An abstract design direction (with issues to solve) to correct all this would be go to to square cross section tubing for the xbar and the aka's. A square socketed within a square resists rotation because of its shape. This all comes back to me now because I built a small trimaran years ago where the aka's inserted into rectangular cross section sockets in the main hull. I tapered the ends of the aka's where they inserted, and then built the sockets using these as a form--so the fit, when the aka's wedged in tightly, was near perfect. Only thing needed then was a piece of line to hold the aka's from sliding out.

But we still need some sort of work-around here it would seem, because that's a whole redesign, and at that the approach would cost in other ways if taken on the TI.


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PostPosted: Mon May 14, 2012 3:24 pm 
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Joined: Thu Aug 16, 2007 2:25 pm
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Location: Central Coast NSW Australia
I could be wrong but I have always considered the rotational play of the knuckle in the x-bar a design feature. Once the early connector tolerance issues were sorted there have been very few reports of disconnection problems and those reported were probably due to operator error (not locked in properly). So I don't see excessive play at the connection as a problem if it was intended in the original design. :?

The loose rivets though, are a problem. To me it seems similar to the play that developed in the original pin connector on the AI- which was a well known issue.
I'd always thought Hobie went for the new knuckle design as a fix for this problem?


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PostPosted: Wed May 16, 2012 1:46 pm 
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Joined: Fri Sep 19, 2008 4:07 pm
Posts: 403
Location: CLEARWATER, MN
After I got my TI, I also noticed that there was what I considered to be excessive play in the movement of the akas in and out of the ama sockets.
I talked to my dealer. He found that Hobie had replacement bungees and bungee socket 'locks' that were considerably thicker than the original OEM bungees.
I replaced the bungees and socket locks.
The new bungees were much thicker than the old ones...it now takes quite a pull to lift the bungees over the 'eye posts' on the akas. The connection stays tight.
Even in very rough water, the TI amas stay tightly connected to the akas!


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PostPosted: Wed May 16, 2012 2:14 pm 
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Joined: Mon May 31, 2010 4:13 pm
Posts: 205
Location: oki - jp
@tidalwave i think you are talking about something different than the OP was referring to.


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