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Deck Delamination
http://www.hobie.com/forums/viewtopic.php?f=15&t=41637
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Author:  WolfgangKornwebel [ Fri Mar 16, 2012 6:13 am ]
Post subject:  Deck Delamination

I'm searching for repair advise to correct a large "soft spot" on the deck just aft of the centerboard. It doesn't seem as though simply injecting some resin into the deck will fix this....any ideas?

Author:  srm [ Fri Mar 16, 2012 9:41 am ]
Post subject:  Re: Deck Delamination

July/August 2009 Hotline "This Old Hobie" article.

sm

Author:  samcc99us [ Fri Mar 16, 2012 11:08 am ]
Post subject:  Re: Deck Delamination

Going through the hull seems like a bad idea. I just did my port hull upper deck aft of the rear crossbeam with the injection method. I would try to go through the existing hatch, or do the injection method, cut out a hole and put a second porthole in that area.

Author:  srm [ Fri Mar 16, 2012 12:34 pm ]
Post subject:  Re: Deck Delamination

Simply adding a porthole to the area is not a good idea. Portholes are no where near as strong as a properly laminated composite sandwitch. Just adding a porthole will allow the soft spot to continue to grow.

If it were me, first thing I would do would be to inject resin. If the deck is delaminated, then regardless of what other repair methods are used, it needs to be re-laminated. So start by doing the injection.

If the deck is still soft after injecting, then likely one of the fiberglass skins has fractured. The skin would then need to be reinforced either with additional glass, or by also adding bulkheads as described in the article. You could access the inside of the hull either through the bottom of the hull, as described in the article, or by adding a porthole (only after injecting resin).

There are a couple advantages by going through the bottom of the hull. First is that you don't have to re-build the sandwich layup when you patch over the hull since the bottom of the hulls are solid fiberglass. You also don't have to deal with repairing non-skid. The second big advantage is that your access hole is on the opposite side of the hull from where you're doing your repair. This means you don't have to reach around 180 degrees to try to work or to see what you're doing. Working inside the confied space of a Hobie hull can be very difficult.

sm

Author:  MBounds [ Fri Mar 16, 2012 3:12 pm ]
Post subject:  Re: Deck Delamination

srm wrote:
Simply adding a porthole to the area is not a good idea. Portholes are no where near as strong as a properly laminated composite sandwitch. Just adding a porthole will allow the soft spot to continue to grow.

If it were me, first thing I would do would be to inject resin. If the deck is delaminated, then regardless of what other repair methods are used, it needs to be re-laminated. So start by doing the injection.

If the deck is still soft after injecting, then likely one of the fiberglass skins has fractured. The skin would then need to be reinforced either with additional glass, or by also adding bulkheads as described in the article. You could access the inside of the hull either through the bottom of the hull, as described in the article, or by adding a porthole (only after injecting resin).

There are a couple advantages by going through the bottom of the hull. First is that you don't have to re-build the sandwich layup when you patch over the hull since the bottom of the hulls are solid fiberglass. You also don't have to deal with repairing non-skid. The second big advantage is that your access hole is on the opposite side of the hull from where you're doing your repair. This means you don't have to reach around 180 degrees to try to work or to see what you're doing. Working inside the confied space of a Hobie hull can be very difficult.

sm

The only problem with doing that - where he's got the problem - is you've got a big block of styrofoam in your way (the flotation block).

Author:  17Novice [ Fri Mar 16, 2012 6:19 pm ]
Post subject:  Re: Deck Delamination

My ancient 17 had a soft spot in the deck. I took the Laser dudes advice and injected GitRot epoxy. They recommend it because it is slow cure and ultra thin so it soaks into fractured foam real good to firm it up. Worked for me. Rock solid. If injection dosnt work you can still perform major surgery. If this hadnt worked I would have sawed thru the top layer of deck then peeled it glassed the inner layer and stuck the deck back on. Who needs perfect non skid anyway?

Author:  samcc99us [ Fri Mar 16, 2012 7:27 pm ]
Post subject:  Re: Deck Delamination

How's the GitRot repair holding up? That is my only concern with this method, longevity and preventing future soft spots. I used resin research composite pro system in conjunction with a light amount of west system's 410 filler. Drilled a bunch of 1/8th holes and injected epoxy. So far so good but it's only been 24 hrs and the boat hasn't touched the beach yet.

SM,

I'm sure you have a wealth of knowledge related to the h17 and h18 and there particular construction methods, and how to fix issues with these boats. My intent was not to suggest sticking a porthole in and calling it a day, but adding the hole to effect a repair from inside the hull. Seems that my thought and yours might not work if there is a giant chunk of foam in the way...

Also, just FYI, I build some of the highest strength to weight ratio full composite structures in the world on a daily basis...I'm not exactly a newb when it comes to laying up very very expensive carbon and core materials.

Author:  srm [ Sat Mar 17, 2012 6:50 am ]
Post subject:  Re: Deck Delamination

The foam flotation block can often be cut and moved out of the way.

sm

Author:  17Novice [ Sat Mar 17, 2012 5:34 pm ]
Post subject:  Re: Deck Delamination

>> How's the GitRot repair holding up?
2 seasons and still solid. Your mileage may vary.

Author:  Quarath [ Tue Mar 20, 2012 10:36 am ]
Post subject:  Re: Deck Delamination

I am about to do the same repair. How can I tell if the Glass is fractured. What do I look for? Is straight epoxy better for getting into all the voids or should it be thickened. I am considering using the West Systems six10 in the pre-made tube to inject with if the tip is small enough for a 1/8 hole.

Also I can't get the non-skid even remotely clean Previous owner had put in 3 ports on each with lots of silicone. I may attempt to re-glass in the forward 2 someday. I think eventually when I get to cosmetics I may take the non skid off completely and attempt to recreate with gel-coat, live without, or use non-skid paint to replace. This boat will likely never be used for anything but recreational sailing again. Any thoughts on this?

Author:  MBounds [ Tue Mar 20, 2012 10:51 am ]
Post subject:  Re: Deck Delamination

Quarath wrote:
I am considering using the West Systems six10 in the pre-made tube to inject with if the tip is small enough for a 1/8 hole.
It's too viscous and won't penetrate into the voids like Git-Rot will. Don't waste your money on it.

Author:  Quarath [ Tue Mar 20, 2012 9:01 pm ]
Post subject:  Re: Deck Delamination

good to know

Author:  gmhendo [ Sun Mar 25, 2012 7:29 am ]
Post subject:  Re: Deck Delamination

samcc99us - I don't suppose you could come up with some carbon cross beams for the 17? I know that alloys do crack, and that there are only a limited number of alloy ones out there...
Not class legal I know, but what happens after the beams are no longer available?

Author:  marcusnans [ Mon Mar 26, 2012 12:42 am ]
Post subject:  Re: Deck Delamination

this is what i did on my 17:
viewtopic.php?f=20&t=36116

Author:  Quarath [ Mon Apr 09, 2012 1:15 pm ]
Post subject:  Re: Deck Delamination

So what is the process if some of the drilled holes did actually go all the way through?

And what is the process if you set your bit stop and test the first 2 or 3 then went gung ho only to find part way through that the bit stop had slipped and several holes have gone all the way through?

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