Fiberglass Hull Repair

Discussion in 'Boat Repair Help' started by glenmorebuckman, Aug 26, 2007.

  1. glenmorebuckman

    glenmorebuckman New Member

    Messages:
    153
    State:
    Caneyville, Ken
    I have a fiberglass tri-hull boat and when I pulled the plug after some fishing the other day water drained out which pointed to a leak. I put some water in the boat and low and behold there is a hairline crack on the bottom about 8 inches long with about 2 inches leaking out the water that I put in. The crack is in the gelcoat and apparently let water into the fiberglass which weakened and now leaks. The bad spot is about a 1"x3" area. What would be the best way to fix this. Epoxy Fiberglass resin or polyester resin. Will the epoxy bind to the gelcoat if the gelcoat is roughed up some before application? I don't care how the repair looks as long as it's strong. It's below the waterline and an ugly spot would just give it some more character.
     
  2. crusinman2002

    crusinman2002 New Member

    Messages:
    374
    State:
    Mukwonago, Wisconsin
    i know u won't want to hear this, cause i didn't want to hear the same thing, you are goin to have to fix it from the inside out for it to be done right, i've been running an exterior patch, and it doesn't last long. anything on a boat, i would use epoxy resin, specially under the waterline. if u run a search on yahoo or google, for fiberglass boat repair, u get some good info.

    i'm sure mark j will be by eventually to give more info
     

  3. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    I would use epoxy.
    Epoxy will work over the top of vinylester and polyester resins but not the other way around.

    You'll have to get to the inside of the crack and get the bilge dried out.
    If this has been going on for some time you may need to put a fan or two in the bilge for several weeks to get the glass dried out.
    When water gets into fiberglass it runs all of the individual glass strands. If it goes on for a lengthy time the water will wick through the entire hull from bow to stern.
    It will usually leave some signs of wicking behind like a dark oily substance that appears to be leaking out of the fiberglass. This will manifest itself in the bilge usually.

    I never use one pice of glass to repair a hole. On the inside of the hull I start with a piece that covers the area and wind up laying several more layers with each getting progressively larger then the last. Preferabally 2" bigger on each side.
    If the crack is right in the V on the outside of the hull I would take Biax tape, Lay it one side of the V and let about an 1-1/2" extend over the V to the other side.
    For the second piece I would lay it the same way except I would start on the other side of the V and let my 1-1/2" fall to the other side.
    This makes a strong seam and is much easier to fair out to blend it into the hull.
     
  4. glenmorebuckman

    glenmorebuckman New Member

    Messages:
    153
    State:
    Caneyville, Ken
    I cleaned the gel coat away from the crack and the fiberglass is good and clean and white except for the 2 inch length that is leaking. That particular spot is dark and soft. After taking the gel coat off from there it reveals a bad spot of about 1"x3". Would it be ok to just cut this bad part out and remove the gel coat back 4-5" around it, then fill it in with epoxy and feather it back onto the gel coat? It's never leaked before so The bilge shouldn't be very wet.
     
  5. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Its a hard call to make but from my experiences I wouldn't cut whats there out. I'd put the fans on it for a couple of weeks and patch as is.

    Anytime you start cutting glass out you have to replace the integrity and strength of that glass.
    Its easy to take a relatively simple and cheap repair and turn it into a nightmare. If you are experienced with glassing its not so bad.
    Lay the patch on the outside first. From the inside you make sure the crack is filled with epoxy before laying the patches on the inside of the hull.
    You have to get to the inside for an effective repair.
     
  6. Duckpoor

    Duckpoor New Member

    Messages:
    184
    State:
    Illinois
    Had a fixture on the transom that had leaked a while before i got the boat and managed to delaminate a fair section of the glass and webbing that supported the area.
    I was in a panic and had NO Idea what to do about it. Happened to get pointed to this Link and man did it make it all seem so much more manageable.
    Straight talk and great How To, step by step with end explination of each.
    Sorry about the Link but just a bit long to Cut and Paste.

    http://www.boatus.com/boattech/casey/17.htm

    It is not rocket science and material for my repair was less than thirty dollars... and I have done several other handy man fixes on other needed things since I learned the tricks in this material.

    Good Luck and Get after it.

    R Green
     
  7. crusinman2002

    crusinman2002 New Member

    Messages:
    374
    State:
    Mukwonago, Wisconsin
    hey mark... i'm kinda in the same boat here, i have a hole and a small crack in my hull, its right in the V, so r u sayin that instead of cuttin that area out, just to lay a few layers of glass on the outside, then fill the hole and crack with epoxy, and then a few layers of glass on the in inside? if so that will make it alot easier than cutting a big hole and having to fill the hole back up. i'm willin to cut a hole and fill it back, i've already read up on how to go about doin that, but with goin this other route, will that be a good permanant fix?
     
  8. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Thats the way I would go. Obviously the hull has thickness to it.
    I wouldnt just use epoxy to fill a hole but I would incorporate small pieces of fiberglass to fill that void along with epoxy. Then do the progressively larger patches on the inside of the hull to tie it all back together into one piece of glass.

    On yours you'll probally have to reshape the V. Thats going to be the hardest part.
    You can use Quickfare to define it and then glass it.
     
  9. crusinman2002

    crusinman2002 New Member

    Messages:
    374
    State:
    Mukwonago, Wisconsin
    the v is still there, i think that my exterior patch would have lasted if it was epoxy resin, i just looked at the repair kit that i had gotten and its polyester resin, which explains why it wasn't bonding to the boat as well as it should have, the hole and crack are letting water through just enough to give the bildge pump a bit of a work out, i'm not sinking on the water, and i've had the boat out of the water since memorial day weekend to let it all dry out in the heat, and i've kept the trailer tilted up so that water won't run into there, i think what i'm goin to do is pull the patch off that i have on there now, and then use epoxy resin to do my glass on the outside, i cant stick my pinky finger in the hole, so i might have to drill a small hole to pour epoxy down into the area, as far as the crack, if i tilt the trailer down after the bottom patch cures, and then pour epoxy in from the top, it should run down the length of the crack, and then i'll let that cure, and then patch it from the inside as well. i'm hopin that will do the trick and i won't have to worry bout it after its done.
     
  10. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Polyster resin isnt waterproof. Gel coat isnt either.
    Epoxy is a much better product with alot more research and engineering backing it up and its about as close to waterproof as you can get. You'll find most boat yards doing fiberglass repair with epoxy these days.

    Buy an 8 inch deck plate and install it over or close to where the hole is in the hull.
    That will give you access to the inside of the hull without having to replace the floor.

    I would make sure I got some glass over the top of that hole in the hull too.
    Do it wet on wet for the best results. In other words, do all your inside patching in one session instead of one piece, letting it cure, and then coming back with another.
    Get the outside first and let it cure. From the inside you can work the epoxy into the hole with the outside patch being your backerboard.
    I would probally mix a little Cabosil into the epoxy to thicken it a little to fill that hole.
     
  11. crusinman2002

    crusinman2002 New Member

    Messages:
    374
    State:
    Mukwonago, Wisconsin
    yeah, i figured that when i put the center of the floor back in i'm goin to seal around it with silicone so that if i ever need to get back in there all i got to do is cut the silicone, undo a couple of screws, and then i'm in with plenty of room to work.

    i had read online that you should only do 4 layers of glass at a time to keep heat build up down, i know you have more experience than i do with doin fiberglass, so i was goin to see if this is true or not, cause i want to get the max amount done that i can at a time, without loosing integrity. i have a week span that i'm doin the patch, getting my epoxy and hardner by the end of the week, so i'll be starting the patch work monday, but i have to have the patch done by next friday so that i can start getting the boat back together. i plan on bein back on the water sept 15th to make sure everything works as advertized.

    thanks for all the help
     
  12. ka_c4_boom

    ka_c4_boom New Member

    Messages:
    2,252
    State:
    Bedford,Ky
    kennith , did you get your boat patched and back on the water today as planned ? curious minds want to know . i maybe repairing a fiberglass boat myself .
     
  13. crusinman2002

    crusinman2002 New Member

    Messages:
    374
    State:
    Mukwonago, Wisconsin

    yeah, sorry, haven't really been keepin up, been doin alot of fishing... got the boat fixed, it dont take water on no more, which is a good thing, i had it out labor day weekend, and had it out a few times after that, still got minnows in the baitwell from yesterday that i got to get out of there and go use before they go to waste. when r u goin to be repairin your boat? mark j gave me some good advice bout how to go about doin mine up, might want to get with him if u got any questions and i'm sure he will have an answer... well.. talk to u l8er
     
  14. papasfishing

    papasfishing New Member

    Messages:
    28
    State:
    cleveland,oklahoma
    hello fellow cat`s... got a old 15foot tide craft tri-hull,and is needing a new floor.would exterior plywood,resin and cloth give the boatanother 10 years or so.marine plywood is more than my ol cat catcher is probably worth.garage kept,buts all i got.
     
  15. Ketch

    Ketch New Member

    Messages:
    469
    State:
    Minnesota
    If your just looking for something to get you by, you may want to just look at getting naturally rot resistant wood instead of going the glass and resin method.

    There are a number of naturally decay resistant species of lumber that have natural oils that preserve the wood

    Find a reputable lumber yard and look for some of the following species.

    Cedar-any type (cedar probably has the least structural rigidity of the woods listed, so you may have to go thicker with it)
    Cypress-this wood is as rot resistant as cedar, but much stronger, and thus heavier
    Redwood-to be rot resistant, you need Heartwood. This is difficult to find and may not be any cheaper.
    Teak-difficult to find, but renowned for its strength
    White oak-not as resistant as the others, but normally cheaper and stronger.

    If you decide on cedar, you may be best off getting 5/4 decking cedar at your local lumber yard. It will probably be cheaper this route.

    Whatever way you decide to go, you should make sure that you use a preservative on it with some UV protection. You can use the stuff that you would normally treat your deck with.

    If you choose to go the resin route over your plywood, make sure you do a lot of prep work before starting. Sand all areas with rough grit to open up the woods pores more (60-80 grit). Make sure if you are going to glass the floor to the sides of the boat that you prep the area to be glassed just as good to prevent peeling and get a good seal. When you drill holes for attaching the floor to the stringers, make sure you pour in some resin before you put the screw in so that the bond is sealed as well. Also, use stainless steel or hot dipped galvanized fasteners to prevent streaking in the wood. Certain lumbers are incredibly prone to streaking.

    If you are good about garaging your boat (most people aren't) I would say you can get by with just rot resistant wood and a UV sealer/protectant.

    If you got any more questions, feel free to ask.
     
  16. badkarma

    badkarma New Member

    Messages:
    772
    State:
    Oxford,Miss
    Mark I've made a living fixing leaky fiberglass boats and have done it on many boats form 6ft dingys to 60ft fishing boats.It's great to know someone but me knows how to fix a leak in fiberglass.

    Mark has told you the 100% best way to fix a fiberglass leak.Take a small hand grinder using a 36 grit sanding disk and grind away the gellcoat so the fiberglass will dry.Epoxy will not stick on wet fiberglass so getting it dry is the frist thing you need do.
     
  17. catfishbill33

    catfishbill33 New Member

    Messages:
    356
    State:
    Clarksville, TN
    Jimmy,
    your input was greatly appreciated on my part to know some one that knows.
    I have a 16ft tri-hull and its a good looking boat.But when i purchased it the person didn't tell me it had been repaired on the bottom.
    A large 2x3[approx]spot has been fiberglassed and you wouldn't see it just looking at it.
    Q: how could I check it to be sure its safe.I have sounded it and its strong but is there any other way to ck it
    thanks again...pm would be fine if you dont mind.
     
  18. CountryHart

    CountryHart New Member

    Messages:
    10,914
    State:
    missouri
    This i hope relates to the post. I have a bassboat that need new jell coat at least on the cap. How hard and costly is this to do?
     
  19. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    You cant re-gelcoat a boat. You can however paint it with gelcoat.
    Gel coating is a mold process. The reason gelcoated boats look and feel so slick is because the mold was gelcoated before the boat was laid in the mold
    Ketch can probally tell you how that works better then I can.

    Using gelcoat as a paint will require a ton of sanding to get it to shine.
    I've heard that there was an additive that cuts down on the sanding.

    Since a re-gel job would be nothing but a paint job in the end I would choose a paint like Awlgrip and have it sprayed. Awlgrip is an awesome boat paint. Deadly as all get out for an amateur to be messing with though.

    Another good choice would be the Hatteras yacht paint.
    Hatteras is the premier fiberglass yacht maker and they dont gelcoat their boats. They paint them right out of the mold. If I'm not mistaken that paint is marketed under the Hatteras name.

    Either way, its going to be a labor intensive project. Less so on the backend of a paint job then painting with gel coat.
     
  20. Ketch

    Ketch New Member

    Messages:
    469
    State:
    Minnesota
    One of the things you really gotta watch when working with gelcote is how much it oxidizes. It may well depend on how old the boat is you are going to repair. If it is a newer boat, and was stored inside, the amount of oxidation should be minimized and you may be able to get that color of gelcote from the dealer or manufacturer.

    If you have to color match, most people don't want to mix colors themselves. Color matching is more of an art at times than a science. There are internet sites with color blotches you can try to match on your screen and they will give you the pigment formula so that you can mix yourself.

    Or, you can take a small sample of your gelcote and take it to a distributor, or mail it and they will mix whatever quantity you want and send it to you. This is often the best when for new people doing this task who don't have an "eye" for color.

    Yeah Mark, there is an additive/thinner you can add to make it cure and shine. It's from a company called Adtec called Duratec High Gloss Clear Thinner (http://www.fiberglassonline.biz/dthgc103.html). The stuff is 25 bucks a quart. I have only used the stuff once, and it sure sprayed nice. It didn't look new when I was done, but really close. This additive also helps get gelcote harder. I believe it was mixed 1 to 1. But it has been a few years since I have used it. Also, don't use it on white, it tends to yellow the white after short periods of time (the rep told me this).

    One thing that most people don't realize is that part of the curing process of gelcote is the depravation of oxygen. That is why it is almost impossible to match the hardness or shine of the original gel. When boats are molded, there is anywhere from 5-10 coats of mold release on the mold (wax). Then the gel is sprayed in. After that hardens (providing it doesn't lift), then the whole mold is sprayed with resin/chop mixture or wet out and then people lay out mat by hand. Once the fiberglass cures, it is pulled out of the mold.

    If you do choose to respray your hull, make sure you are using nowax gelcote on all the layers except the last. Then comes sanding. 220, 400, 600 wet sanding. Then you refill all the air bubbles that mysteriously appear (it is especially noticable on hand mixed gel as opposed to atomized gel from a sprayer). Use a tooth pick tip to dip small amounts of gel into the divots. Make sure you don't add too much hardener to your gel either, as this makes it prone to get air bubbles.

    Hope this helps.

    Oh yeah, one final tip. If you are going to patch a hole, make sure you rough up at least 2-3 inches beyond the farthest the wet gel will go. If not, the shiny surface will create a halo that will make your repair stick out like a sore thumb.


    If its me, I patch it and spray it with Awlgrip.