Stress Repair How-To

Nice straightening job! Regarding the adhesive, it is stiff enough to hold its shape. When you apply it, it will not sag to the bottom. Your priority gluing area is the lower half of the cam column and the immediate surrounding hull surface where the cam column attaches, so don't short these areas expecting the glue to fill in.

The clam shell is simply a convenient and quick method of applying the adhesive. It also looks relatively neat and probably adds additional strength. Also important is that it is a more efficient use of the product. When I did this the first time (no clamshell), it took 2 packets and more time putting it on freehand. What a mess!

When you load up your clam shell and wrap it around the cam columns, glue should squeeze out top and bottom (hopefully); it will not run or sag. I held the PVC in place for about 30 seconds, after which there was no tendency to separate. IMO, trying to apply glue inside the boat by feel with the clam shell already in place will will be impossible to accomplish since the material does not flow. Alternatively, fiddling with zip ties while the glue is setting up will weaken the bond. I think your best option is to apply the adhesive uniformly to the clam shell, install the clam shell around the cam column expeditiously, then leave it alone until it cures.

Roger that, thank you sir! "...so don't short these areas expecting the glue to fill in." What exactly do you mean here? I "think" you mean don't just add adhesive to the upper portion thinking it will run downwards, just apply a uniform smear (1/8" level all over the open clam shell) so that when I push it around the column it will seal and push out the bottom and top. Correct?

I will have a go at this tomorrow or Monday. Right now my new un-opened tube is in our house at 73 degrees F and my working garage is about 85 degrees F. Not my ideal temps to work in but I do live in central Texas unfortunately.

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Thank you,
Roy Niswanger

Yes.

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Thank you,
Roy Niswanger

Nice documentation! Hopefully the cam columns will be problem-free now for a long time.

RR
Thanks for the pics and info. I ordered the 3035 and got it today. I have a very old Outback that I bought used a few weeks ago and wished Id have seen this forum beforehand because I knew nothing about these problems. My first two mini cruises were only for about 45 min and I noticed that my mirage drive was tilted to the right while pedaling. I repositioned the drive each time but it kept tilting to the right. I then noticed the cam lock on the left side of the drive had a very loose bolt, so I tightened it but it loosened within minutes and the drive leaned to the right again.

After researching here I found your excellent post and sure enough the RIGHT side column has a crack but it goes up and down (vertically) I did have about a half gallon of water in the hull so I emptied it out and today made my pvc clamshells. Quick question, just fill one of the halves or both of them with the epoxy? Secondly, is there anything I can do for the left cam bolt? If I tighten it all the way it just keeps spinning. If I tighten only to where it holds firm, the drive pushes upward and it tilts to the right again.

Many thanks ahead of time and I appreciate any thoughts you can give to my problem.

Beemer,

Seems you've registered to get more into this repair and that's great. RR has been very helpful on this forum for sure. Here are my thoughts on your question here:

For the clam shell on the right, using more than you need is okay...using not enough is not okay...meaning you got one shot of this and I would pack as much as possible to provide both a stronger epoxy column and possible sealing properties.

For the bolt, I can't really answer outside of that post I referred you to in my yt video. I would think if you are able to remove the bolt fully then packing epoxy down into the hole and then inserting the bolt with cam and tightening enough (without gluing the cam and if you suspect it might then keep spinning it back and forth until the epoxy sets up). Maybe this would keep the bolt from lifting and keep it in place. But it's risky and it's a final way to go about it. I would research more and take your time.

-Roy

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Thank you,
Roy Niswanger

Appreciate Roy. I just finished doing the right side column and it was not cracked or split that I can see. Since mine is a TANDEM, I couldn't get anywhere near the other side of my rearward pedals to see if that side was cracked. But I felt it with my fingers from my rear hatch and it felt uncompromised. I dont know how long to let this stuff harden and cure fully but Ill give it a day. Then Ill check out the forward pedals and see if I can see anything there. Both sets of pedals have the turbo fins. I wont be using the forward ones very much so Im not in a hurry to do those columns. Maybe Ill get to them over the winter as I go back to MD to work from Sept 20 until Dec 1st and by then I wont be in the water.

Ill go to Home Depot and get some marine epoxy and try the left side bolt repair after I give this yak a shakedown cruise on Monday or Tuesday and post the results. But, the repairs look to be good and the clamshells are butting together nicely, so it looks as if this 73yr old dude with short arms and bad shoulders gotter done@! LOL Appreciate all the info and thanks to the Florida Bro for answering my emails offline.

beemer sounds like left cam bolt socket has stripped its thread. I think there are posts somewhere on here that suggest using epoxy which effectively rethreads the hole without preventing the bolt from being readjusted when required. Not sure if this entails turning bolt during cure time to avoid adhesion to bolt itself.

Well, my cam column repair must have again failed because I started getting fractures/cracks around the area where the drum shaft sits and the cam bolt screws into the hull. Here's why I think so:



I will then later, post how I retrofitted a pair of after-market Click-n-Go clips that I also cut and modified (had SS tig welded).

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Thank you,
Roy Niswanger

And here's my final repair, a retrofit of the MD Click-n-Go:

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Thank you,
Roy Niswanger

Another reason why I think Hobie should create an internal frame made of carbon fiber or alloy where the seat, MD support columns, scuppers, mast column, and any other weight-bearing, high stress zones exist...

First, a bit of background in my first video above describing how the cam column's weakness (breaking) causes a delta in opposite force vectors leading to cracks was a quick video I did for a user of the facebook Hobie page where a guy who's local to me posted his 2007 Revo with cracking that he just bought. Both of his cam columns are fractured. I'm going to help him out with my modified Lightning Kayaks Click-n-Go retrofit.

Now, onto methods to reinforce high stress areas of PE hull kayaks. Hobie engineering is undoubtedly the number one in the world when it comes to kayak design maybe not for long but they've had the history and capitol to have these sorts of teams build and design for them for sometime now. Now try to think of any PE kayak that you've seen some "other" material other than PE itself that's used to reinforce structure. See, if it's not PE then it will require mechanical fastening. Not to say some block of CF with LSE adhesive would solve the issue, it's just their engineering directly attacked the problem and completely eliminated the cam locks and re-designed from the ground up and so far that has held up. Now the 360 receiving design is much different so we are in a new chapter there, but for the click-n-go, it's pretty rock solid. So far my modified click-n-go is working great, cutting the plates down to lower where the drum shaft sits by about 1/2" is the key to making this retrofit work as nearly stock/default works with the drive.

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Thank you,
Roy Niswanger

Okay, then Hobie engineers can take another page out of Nature’s cookbook and use beetle technology to build a stronger hull:

https://apple.news/A9kOAOPXcTOG-NEYcxXTK2Q

Fun article! I wouldn't be surprised if they do just that, well at least give it a thought. The material chosen is directly related to fabrication process and cost. Anyway, it was a Hobie engineer back in the late 90's that studied penguin movement through the water who ultimately developed the mirage drive.

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Thank you,
Roy Niswanger