Another Fiberglass repair thread, Malibu response ski boat...

[Faabricator909]

Hi g uys, this seems to be the goto place for fiberglass boat repair. I have 95 Malibu Response ski boat with some damage to the bottom of the hull that IS letting water in, enough that I the bilge needs to run, not continuously, but run none the less. After reviewing some things on this board, some people love epoxy resin, others not some much and do not recommend it for repair.
My plan was to grind it down, use US composites epoxy resin,use 1708 biax for the majority of the repair, then finish it off with 7725 cloth. Then fair it with epoxy and glass bubbles, then finally white gel coat... it's on the bottom of the boat, don't think a color match is crucial lol.
Am I on the right track, or in left field?

 

[boedekerj]

I'll tell you how I fixed mine, but others may know better. Mine was accessible on the inside. I started by taping the keel to a point on the outside. (I used two pieces of painters tape to create a sharp "v". Then I mixed up a nice batch of Peanut butter, but instead of using 1/4" chopped fibers, I hand tore some CSM for the mixture. I used this to push into the crack. My emphasis was not to build up a ton of PB like a filet, but just to get good amounts of resin with some long, multi-directional strands in that void. Then, I did a 3" strip of 1708 over the PB, followed by a 6" strip and a 12" strip of 1708 over that. On the outside, Pull off the tape, clean with acetone (of course, we should be doing this every time). I had to shape some the Peanut-Butter "hash" mixture that I'd pushed through to roughly the same shape as what the keel was supposed to be. Then I marked (this was important for me, as I'm not a good "sight-er") and feathered 6" up either side, wrapped a 12" 1708 strip, then 9", then 3". Shape, fair, gelcoat, keel protector. If you had a vacuum assist system to pull in resin, that may make all of these unnecessary, but I don't know that system at all. All in all, between outside and inside, I added 6 layers of 1708 to the the front 6' of the keel area, which was overkill, but I had the material. I do believe that pushing up at least 6" on either side is crucial to distribute the pressure over a larger area of the hull, otherwise if you just fill the crack and wrap it over once, it will push back through the first time you rub the beach.

 

[Woodonglass]

As stated it's best to do an inside/ouside repair. IF this is not possible then Grind and feather 4-5" on both sides of the crack. You wan the glass very thin at the crack. You will then use successively larger patches to build the thickness back up. It's easiest to do this on your work bench. Lay down some plastic and cu some 1708 that's about 5" wider than the crack and about 3 ft long. Lay it on the plastic cloth side down and wet it out, Cut another piece 4" x 3 ft and immediately place it on the first piece and wet it out, Another 3: x 3ft and finally a 2" x 3' piece Carry the entire patch to the boat and apply to the crack (Make sure the patch area is ready by wiping with acetone) use a bondo spreader and you hands to get it to lay down and conform to the keel. You have to work fast cuz you only have about 20 mins from thetime you mix the resin until it starts to harden, You can use Epoxy but...I'd use the 635 Poly resin from US Composites. Do your fairing and then Gelcoat or paint.