Fixing a broke chine.

[f_inscreenname]

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

[gcarter]

I haven't seen the inside of your hull, but it's doubtful the "strake", the chine is the outside corner, is a separate component. I would imagine the strake is glassed over with a void under it. Donzi fills these voids w/putty before glassing over from the inside.
Take a look at; http://www.donzi.net/forums/showthread.php?t=50476&page=4 and start reading at post #47 and you'll see what I mean.
I think to properly repair the strake, I would remove (cut out the glass covering the strake) and repair it from the inside, and then fill the void in the strake w/thickened epoxy, and glass over flush.
Or, you could repair the outside of the hull again (least desirable). When repairing glass, grind through the glass where the glass edge is tapered at about a 12:1 ratio, i.e., if the glass is 1/4" thick, the ground edge would be about 3" wide. In this case, with the radical contours, this may not be possible, so it would be another reason to do it from the inside.
When your laying up the glass, use mat bonded material. The first layer would be mat towards the existing surface. This first piece would be a very minimal size. The next layer would be larger and so on until you have built up glass to approximately the same thickness as original. If you're working from the inside, use a piece, or pieces, of melamine to make a tool to lay the glass on. The resin won't stick to the melamine. This will help tremendously when trying to form a shape.
I hope this helps.:smash:

[BlownCrewCab]

I Think any running surface glass work needs to be fixed mostly from the inside. then, depending on how much grinding was done to eliminate the cracks and damage, an appropriate amount of glass from the outside also.Tapered Like GC said. once, racing in Key West after Wednesdays race we noticed some bad cracks in a strake and because of the inner liner could only be fixed from the ouside, well in saturdays race when that patch came off so did a bunch of other glass. a hole about the size of a pack of smokes was now big enough suck up a beach towel rolled up. we couldn't fix it from the inside in the parking lot with just rental tools. had we fixed it from the inside I think it would have lived...

[f_inscreenname]

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/index.php?topic=253.0 (http://www.supernova19.com/forumcw/index.php?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.
http://img294.imageshack.us/img294/713/95527494gk4.jpg
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.
http://img132.imageshack.us/img132/5340/45844649jf4.jpg
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.

[MOP]

The repair let go on you, I would tape over the hole and dump foam into that cavity then enlarge and repeat the outside repair. That should stiffen the whole area, I ran into the closed cavities a few times.

Phil

[f_inscreenname]

I’m going to use this.
http://www.uscomposites.com/foam.html (http://www.uscomposites.com/foam.html)
The 16lb stuff.
If it works out I will do all the strikes and chines. Even the smallest ones are hollow. Maybe not the 16lb stuff but something to keep water out. I’ll use the 16lb in the repair area. They say you can hit it with a hammer and not hurt it. It should be good enough to back up the new glass.
Tilt the boat up, drill a few holes, mix the stuff up, pour it in a empty caulk tube and pump it in. I can only hope its that easy.:wink:

[MOP]

Shoot an inside pic of the box area, I should be able to give you an ideas of just how to get the foam in screwing it up. You want it filled but you don't want to stress/damage anything from the foams expansion which can happen fairly easy. I worked with the local Boston Whaler rep for several years and did my fair share of screw ups early on!

[f_inscreenname]

I am doing the math now so I don’t over fill it.
Plan on drilling 2 or 3 small holes in the side of the strike at a calculated distance from each other and start from the transom and work up the strike in small batches. I’m thinking the extra holes will let air out so it don’t “pop” and also give me a progress report as I go.

[mrfixxall]

looks like your bondo cracked,,first you shouldnt use bondo under water,its acts like a spongue and will hold water..If your in a cold state then it will freeze and crack so get rid of the dondo and get some filling powder and mix it into to resin to act as a filler..second did you use a fiberglass roller? https://www.minicraft.com/retail/standrollers.htm thats what gives your mat the stregnth it needs..Apply the resin to the mat and roll it out,you want to push the mat as close to the repaired serface as possible this is where you get your stregnth..third how much mek (hardener) did you mix into the resin? if you mixed too much then it wont have no stregnth and it will crack or shatter..when im done doing a job and with the left over resin that cured i will usually wack it with a hammer to see if it shatters,if it doed then i start over..fourth always use a ruff 18 or 24 grinding disc,the ruffer the better so the resin and glass mat can melt together..fifth you really need to get inside to repair it from the topside also or you will keep repeating the repair..good luck :)

[f_inscreenname]

http://img501.imageshack.us/img501/2137/55279655ux9.jpg
The 16lb stuff (http://www.uscomposites.com/foam.html (http://www.uscomposites.com/foam.html)) I used to fill the strike only expands 4 times it's wet volume. I think more like 3 times but I was using it in 70 degree weather. They do say you get a better expansion rate when it's over 80* but I will take the more denser version for what I am doing. Just testing it I put some of it in a Dixie cup and let it expand. I then threw it on a concrete floor, hit it with a hammer and dug at it with a screwdriver. It's all they say it is. Just the slightest dents so it should work fine. It also is as light as a feather. I figure the whole chine may add 3-4lbs to the boat.
I then did 14 layers of mat and glass over 7 days expanding the width of each layer. That should hold it this time. I also used a home made roller and a crap load of brushes to make sure there was no bubbles or air pockets. At the very end I used a little fiberglass bondo to smooth it all out but the majority of it was less then a sheet of paper thick.
A quick movie.
http://www.youtube.com/watch?v=yarQ-GF6zII