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PostPosted: Mon Aug 06, 2018 1:16 am 
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Joined: Mon Nov 10, 2014 6:20 pm
Posts: 139
Location: Pula - Sardinia
Unfortunately I am into the drivewell leak problem. After searching in this forum i realized it's a "famous" and tremendous problem and most comments are "change the hull". Change the hull for a small crack in the wrong place... isnt's a very smart solution.
I wonder if the other people who had the same problem solved it in any way different from getting a new hull.

My question is is any of you ever thought to make an "armour" or metal jacket to the drive well. It could be fixed under the click and go clatches and could have 2 small metal platforms in the 2 points where the drive now is pressing againt the plastic.
i think this should also be an improvement for Hobie, cause the drivewell leak is becoming a famous weakness point for all the mirage drive powered hulls.

what do you think about it?


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PostPosted: Mon Aug 06, 2018 3:29 am 
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Joined: Thu Aug 16, 2007 2:25 pm
Posts: 2851
Location: Central Coast NSW Australia
Sardinian Islander wrote:
Unfortunately I am into the drivewell leak problem.....
My question is is any of you ever thought to make an "armour" or metal jacket to the drive well.


Not that I’m aware of SI. It’s an interesting and innovative idea.
There has been discussion on a replaceable drivewell way back in 2011, which you may find helpful here: https://www.hobie.com/au/en/forums/view ... 75&t=35131
The relevant discussion begins with my comments on page 3.

Have you sent pics of your drivewell crack to Hobie? A drivewell crack in a 14 TI is unusual. The rotomolding process is not perfect and faults can occur. It would be worthwhile getting it properly assessed to see if it is a manufacturing defect.


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PostPosted: Mon Aug 06, 2018 5:15 am 
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Joined: Mon Nov 10, 2014 6:20 pm
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Location: Pula - Sardinia
this is how everything started.

https://drive.google.com/open?id=137-9p1Czi6JsUkPwT9b6wXtNopwjtXVD

now the situation is worse


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PostPosted: Mon Aug 06, 2018 3:06 pm 
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Joined: Tue May 27, 2003 12:44 pm
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Location: Oceanside, California
That looks more like a hole in the forward wall than a crack in the ledge? Maybe the drive was not properly mounted in the well and was forced forward upon pedaling. The spine may have pierced the forward wall where it should never come in contact under normal use.

Cracks in the drive well are not a common issue and have not been much of an issue at all for many years. The original problem started back in the late 2000's with the introduction of Turbo fins. We corrected the problem by reinforcing the ledge area and closely monitoring the plastics quality. Newer boats very rarely have the original ledge type crack appear.

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Hobie Cat USA


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PostPosted: Tue Jul 07, 2020 5:03 pm 
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Joined: Sun Apr 26, 2009 9:22 am
Posts: 26
Location: Shalimar FL
"Metal Jacket", sort of, using an embedded stainless steel screen:

I wrote Hobie to complain about the drive well crack they told me to buy a KC Welder with color rods and directed me to an instructional video.

The repair in the video used a stainless steel screen. The bond was very impressive. I could not manually pull it apart. Previous tests without the screen always seemed to fail. I think the trick is to use the screen to mechanically interlock the plastic into the screen and create a plastic-metal-plastic bond. Plus, the screen provides extra strength, particularly when placed on both the inner and outer walls.

Here’s an unofficial step by step. Do this in a well ventilated area with PPE as needed:

1. Watch the video sent from Hobie: https://www.youtube.com/watch?v=6gAFsDDNm2o
2. Run tests on a sample piece. A good source of thick HDPE is most likely your neighborhood street side trash can. Roughness does not matter because the surface will get melted away. You should be able to get a bond you cannot pull apart. It’s probably important that both surfaces are very clean.
3. Improve your access to the area. For the forward end of the drive well on the AI this means removing the mast cup. Its not that hard to do and is well worth it.
4. Put your drive in the well and get a feel for clearances. Mine had plenty of room for plastic.
5. Do the outside first because its easier and it serves as a good warm-up for doing the inside. Fashion a piece of screen running from the top of the interface, through the drive well, and to the underside. My piece was about an inch wide on the underside and narrowed into the gap.
6. Press the screen into the plastic until it is flush with the surface. My method was to press the iron into one spot at a time, as shown in the linked video. After pressing in the screen, pile on the filler plastic.
7. Repeat for the inside using a v-shaped screen described earlier in this thread.

So far the patch is holding up. I will re-post if it fails, but it looks solid.

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Greg
Red 2017 AI and red TI 2019


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PostPosted: Tue Jul 07, 2020 5:08 pm 
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Joined: Thu Aug 21, 2014 6:43 am
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Location: Chalfont Pa
I like the metal jacket idea. It could be a 2 piece, one from below and one from above with a sealing compound between the vertical sections.


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PostPosted: Sun Nov 29, 2020 5:30 pm 
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Location: Shalimar FL
Update: After about 30 hours of use, the repair I described above, using a flexible stainless steel screen pressed into melted plastic, inside and out, is still holding.

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Greg
Red 2017 AI and red TI 2019


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PostPosted: Sun Oct 10, 2021 10:32 am 
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Joined: Sun Apr 26, 2009 9:22 am
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Location: Shalimar FL
Second update:
I originally used stainless steel screens cover the crack inside the hull and on the bottom of the kayak:

Leak has reappeared! The metal screens are still embedded and there is no tear, but water is getting through somehow.
A new, and very noticeable symptom is a crunching sound as I pedal. I am certain the sound is not coming from the drive itself. It sounds as if the walls of the crack inside the drive wall are sliding against each other.

To fix it, I drove four stainless steel screws from the outside of the kayak at an angle through the crack without piercing the inside wall of the kayak. Two screws on the left and two on the right side of the crack. I drilled a blind undersized pilot hole (not all the way through) to ensure the angle is correct. I cut the head off the screws slightly below the kayak plastic surface with the abrasive wheel on a Dremel. The heat from the cutting operation seemed to melt plastic into the screw, however, polyethylene does not flow well when melted, so I cannot vouch for how well it bonded to the threads of the screws. I covered the repair from the bottom of the kayak without another stainless steel screen using the plastic welder (leaving the previous screen in place). The finished product looks pretty good.

I think the screens are required because plastic over the surface is too weak for this high stress area. Plus, the screens help bond the new plastic from the welder to the old plastic on the kayak.

I tested the repair with 20 hours of sailing and have had no leaks so far.

The screws through the crack have eliminated the crunching sound.

A metal contoured jacket from Hobie would be nice. It must sufficiently address the loss of strength.

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Greg
Red 2017 AI and red TI 2019


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