I have 2 cracks in the hull of my southwind jet. I have gotten them all sanded down and prepped on the outside and i am getting ready to cut out the floor to get to the inside so that i can glass them from in there too. The cracks were in the boat when i got it but were not visible when on the trailer so i got screwed  . Anyways, they appear to be from a rock hit and look to have been repaired with some kind of epoxy but they have came back. I have searched and looked at how you guys have repaired some  of the cracks in the bottom of your hulls. I have never done any fiberglass work before. The bottom of the boat seems somewhat flexible around the area where the crack is, now i hope its just because of the break and not because the wood is delaminating or rotted. My main question before i get started is what kind of supplies will i need as far as fillers, resin etc? And should i use woven cloth, tape or mat to do the repair as i want the strongest fix possible. I also planned on adding some braces in the area under the floor in the boat. The floor and the rest of the boat seems very solid, It appears to be 1/4 stringer boat, but i will find out for sure when i cut out the floor. I will try and get some more pictures later on this week, but for now i am just asking as to what kind of supplies i will need to buy to do this correctly.
Thanks

First and foremost, the crack will need to be ground out as much as possible, enough to where the fiberglass resin (or epoxy) and mat actually touch when applied from both sides.

The next thing you need to decide is what materials to use, it boils down to what you're comfortable with and what's readily available to you in your area. I really like West Systems, no smell, several choices of viscosities and curing times, and clean up is a piece of cheese (MEK).

Take your time and ask a lot of questions, the only stupid question is one not asked. 

Prep. is the name of the game, you will probably spend 80% of the time of the repair on prep so don't get in a hurry to apply the glass.

Good Luck!

GT

I have read his thread over a few times studying what he did to repair the crack, I am mosty just unsure on what all materials i will need to do it? Is there a kit that will have everything that i need to do the job as far as fillers etc?

a lot of the pics are gone but you will get the idea
http://www.socaljetboats.com/index.php?topic=1277.0

i just did a crack on the bottom and it was about 10 inches long and an inch wide when i was done grinding. i put masking tape on the outside of the hole so the glass didn't fall through. then i sanded with 24 grit on the inside for about 18 inches all the way around the crack. i used west systems epoxy resin (pricey ) your boat is probably polyester so the epoxy isn't necessary but great stuff and i like it.
any way i went with 3 layers of mat then 3 of cloth staggering them first left then right and so on. get some latex gloves and put more than one set on so you can peel them off as needed. wet out the hull lay your first layer of mat then with little paint rollers roll all the air out. lay the next one and repeat. then start with the cloth, i like to lay it on then use the roller and my hand to get all the air out and finally use a bondo spreader to get all the excess resin out. resin is pretty, not strong. GET ALL THE EXCESS OUT

oh i forgot cut all fiberglass before you mix any resin, you dont want to be in a rush when you start with the resin. (ask me how i know )

hope this helps ralph

disclaimer, this is just how i did it and it worked for me. your results may differ

lots of good info here as well
http://www.youtube.com/results?search_query=west+system+fiberglass+repair&search_type=&aq=2&oq=west+syste

Ok, few more questions. What would be the best kind of mat to use and how much resin and hardener will i need? The area is about 30"x1/2" on both sides. Will one quart do it or should i get a half gallon? I want the highest strength mat, it looks as if the woven roving cloth is the strongest? Do i need to use more than 1 kind of mat or tape for the best strength? And i will not need any fillers if i am using mat to fill the gap, correct?

You will probably go through a gallon, more than half of which you will sand off and throw away 

The lighter the mat, the more the layers, the more the layers, the more control on where the thickness is...Woven roving is for huge areas and a real bitch to work with. Cloth is for finish type work, IMHO stick with the mat and you wont have any issues...

GT

Is there any difference in automotive epoxy like 3m brand as opposed to the west systems epoxy in strength and flexibility? Is there any reason i should use one instead of the other?

They say that there is a marine spec, but I think it has to do with the ultra violet (UV) reactivity, in other words the non marine stuff may yellow if left exposed to the sun, I dunno though

GT

I have a few more pics or i can take pics of anything else if needed. By the looks of things someone has been in there before on the left side and put some expand a foam sh*t in there. Now that i am cutting away at stuff i am thinking about just tearing the whole floor out and replacing the center stringer that looks to have been installed and not treated with anything. Only problem is that my floor is not completely flat, and my mounts or buckets for my seats seem to be glassed to the floor 
Oh and the blueish stuff seeping through one of the cracks is from a previous attempt at fixing the crack by me. I'm hoping this stuff will dry out by tomorrow and i can start grinding away at it or figure out if i wanna tear the whole dam floor out of it and start fresh, which to me seems like a good idea right now.
Thanks

I figure the cutting out of the wet crap wont stop until all of it is gone  But when i'm done hopefully i wont have to do it again for the life of the boat in my possesion. Now, how do i get the glassed on seat buckets off the the floor material? Just bust it off with a chisel or try cutting it with some sort of small saw? Oh and that dam knob is stuck on there good
Thanks

I figure the cutting out of the wet crap wont stop until all of it is gone  But when i'm done hopefully i wont have to do it again for the life of the boat in my possesion. Now, how do i get the glassed on seat buckets off the the floor material? Just bust it off with a chisel or try cutting it with some sort of small saw? Oh and that dam knob is stuck on there good
Thanks

Roto Zip or spiral saw is prolly the best, easiest and quickest, with a flexible attachment. Should be able to cut out those bases like a surgeon! Handy tool to have around the house anyway, can cut anything in any shape!

And the knob is cool, will impress the "seat covers", particularly the blonde ones! (That's the SECOND boat I've seen with the F/R lever seat mounted like that! I gotta try that on one of these things!)

Ray

Got some more of the floor torn up and got the front seat buckets off of the floor! They had a crapload of resin holding them down, damaged one a little but i will patch it up when i get my resin and mat. Going to tear the rest of the floor out tomorrow along with the board under the dash, not sure what its called. I noticed that there are 4 big green inflatable disc looking things under the bow, i imagine that they are for flotation, but if the boat is sinking i do not think they will do much good? Do they need to be re installed or can i throw them away? Got a list of stuff made up to order for the glass supplies. What kind of wood should i use to replace the center stringer/floor support, it looks like there is a 2x4 in there right now, and what thickness wood should i use for the floor?
Thanks

Looks like you making some damn good progress. Glad to see your using the mask while doing all that work. 

im not sure if it matters or not, but, i think i would remove the motor before i glassed a stringer in... Its bad enough that it will be on the trailer and not on 3 points. My concern is that the hull will be twisted with the extra weight in it and not relaxed.......
just thinking out loud

not sure maybe gt will chime in, when my stringers were done the boat was stripped and off the trailer. then supported on the left and right sides at the transom then at the bow. i was told they do it like that so the hull is relaxed