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Fixing a broke chine.

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Old 04-27-2008, 01:10 AM
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Default Fixing a broke chine.

It’s to hard to explain with just words. So I made a video. Watch this and tell me what you think I should do.
http://www.youtube.com/watch?v=5KmemM_uk0M
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Old 04-27-2008, 08:45 AM
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I've never seen a chine added on to the exterior of a hull. It would seem like way more work to make it separately and bond it on. Not saying it isn't possible, just that I've never seen it. You might want to investigate furter- look inside the bilge at the bottom contour.

Having said that, if it is a hollow cavity...

There are injectable, grout-filled epoxies available. I use one that I've posted about before. It costs about $1.50 an ounce which is a little less than a cubic inch. It would cost mucho dinero to do what you're considering.

There are rigid foams available- you'd need to find one that was closed-cell so it wouldn't fill with water. They would give you a little bit more support but nowhere near what the first solution would provide. Would have a fraction of the cost though.

I suppose you could stand the boat on its nose and pour the cavity full of resin. Without some sort of reinforcement, it will have more support but probably not more strength.

Consider this though- most boats perform fairly well in their intended purpose. If you're running hard, wave jumping, etc., the hull might not be up to what you're asking it to do. Throwing more money and effort into it may be futile. You'll just move the likely failure point to the next spot down the chain. If you want to run hard, maybe you boat is telling you it's time to move up- while there's still some value left in your existing boat. If you bust the hull, it's not going to go too far as the down payment on the next one.
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Old 04-27-2008, 10:36 AM
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cool video. where the crack is from the previous repair and the roller on the trailer. It looks to me that the roller and the repair are putting pressure on that area and causing the crack. Try jacking up the boat in that spot with a floor jack and see it the hull flexes. that could be the problem. it's worth checking.
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Old 04-27-2008, 12:38 PM
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I noticed the same thing as offshoredrillin; seems to be a stress point near the roller. what does the inside structure look like? did something pull away from or delaminate that's visible from the bilge? the hull looks like my old Formula 20' (202). if you'd just like to get a few more seasons out of her why not inject some fibrous epoxy mix. there's b ound to be something less expensive than what chris s. mentioned. btw, since i couldn't tell from the video, is all of the uneveness the bottom paint or are there some blisters? - best of luck to you- jeff
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Old 04-27-2008, 12:56 PM
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You all bring up a couple questions so lets see if I can answer them.
This was the original repair. http://www.supernova19.com/forumcw/i...hp?topic=253.0

As for getting to it from the top side is near to impossible. The top would have to come off and then the inner pan and then I would have to cut through 2”s of the hull to get to it.
Here is a picture of it before I made the repair.


This is from the keel side looking out. As you can see there is a void and it goes all the way out and to the end of the chine and gets larger as it goes. Like I showed in the movie the beefy part of the hull runs at the angle and the chine (for lack of a better term) is just a hollow box corner that was stuck on the outside of the hull to square it off.
When the boat is at speed it lifts and runs on these chine’s (the top ones are only used when going slower, very hard turns or in very rough water) so less hull is in the water. Less hull, more speed. But there is a lot of pressure on these guys.


The last repair I did held up for a good 6 months and I know I hit something again (I herd it) the last time I was out last fall. I just couldn’t imagine it was in the same spot but there is another mark.
The trailer roller does sit close but there is no flex in the hull. It’s solid as a rock. The boat is built like a tank except for this one part. It’s one of Brownie’s boats remade by Allmand. Allmand makes tanks. Brownie makes awesome designs. Put the two together and you have a awesome looking tank. My GPS tells me that every time I go out. The strange thing is, the “chine box” is actually thinner in construction the sides of the boat. I guess it’s like the egg design. The right pressures in the right places and you will never crack it but a simple strike in the right place……
As you can see in the post from the other forum I did make the patch much larger then the original damage. Maybe I used the wrong glass or mat or not enough of it. I’m not a glass guy by a long shot and glassing upside down, I end up wearing more then I ever get on the hull.
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Old 04-27-2008, 05:08 PM
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Lotta work

#1. What your looking at is called a "Strake". The "Chine" is the corner where the side of the hull meets the bottom. Speed boats have a "Hard Chine". Blowboats have a "Round Chine".
#2. Looking at all your pictures on all the web sites. Your hull was cast in a mold and the strakes were in the mold. The strakes are a structural a part of the hull. The hull was cast and then an insert was installed inside it.
#3. Looking at your previous attempt at repair you have actually weakened the structural strength of your hull. If this was a slow industrial boat. I would say just patch it from the outside. But this is a go fast boat so you will have to patch it from the inside so you can maintain the original hull profile. It's a lot of work.
Stage One: Sand (not grind) from the repair to about a foot in all directions. Use cheap bondo to reshape the damaged areas and sand everything to the original hull profile. Hit it with some surfacer primer finish sand and shoot some cheap automotive urethane and let it cure. Use cheap auto stuff up till here because its only temporary.
Stage Two: After the urethane has cured compound it and wax it with release wax. The blow on some PVA release agent. Shoot it with some black gel coat. Then lay up some glass starting with 2 layers of thick mat. Let it cure completely (a few days). Then smack it with the palm of your hand to break it loose. A little water will help if you can squirt it in between. Gently peel off your temp mold of the original hull profile. Let it cure some more but support it so it doesn't warp. and don't leave it in the hot sun. Compound it and polish it then wax it and blow on some PVA release agent. Store it so it doesn't warp. In the mean time sand around the immediate area of the repair to get rid of the release agent wipe with acetone.
Stage Three: Neatly cut an access hole in the inner liner big enough access the whole repair area. Grind out the damaged glass and feather the edges. Grind the surface back from the repair a foot in all directions. Note if you run into a corner like the transom go a foot past the corner. Wipe it down with some acetone.
Stage Four: Block the temp mold in place make sure you don't warp it with dips and dimples. Sometimes you need to back the mold with some plywood in the flat areas. Lay up the repair from the inside. Lay it up a little thicker than the original hull laminates using the same materials as the original hull. Let it all cure then gently remove the mold. Sand the whole repair area including all the urethane painted areas shoot vinylester primer over the whole thing then after that cures shoot on the desired finish.

Last edited by 29Firefox; 04-27-2008 at 05:14 PM.
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