Hull Damage Question

Same way you repair an actual hole, taper the edges 8-12:1, lay up glass in staggered pieces, fair. A layup that uses coremat is treated as a solid layup and the repair uses just glass to build up thickness. The repaired area ends up stronger and a little heavier.
A foam cored sandwich is a two stage affair, cut out a generous piece of outside skin, remove foam, repair inner skin, put in new foam over putty, put on a new outside skin with appropiate scarfs to the old glass.
For a rip like that I would start by first glueing it back with superglue, that insures I can start grinding on a reasonably fair surface and don't have to deal with an actual hole.
If you do everything with poly or vinylester resins you can regelcoat after fairing, with epoxy you need to paint. This beeing an underwater repair either is fine, it gets antifouling anyway. If it were above water you would need to decide if you want to paint the whole boat now or later, eventually the colour difference between old and new gelcoat will show.
The whole thing is expensive because of all the grinding and fairing involved, the manhours add up quickly.

 

I think I will have to consider destructive testing / core samples . If anyone knows of good repair shops in Ontario , please forward them . Answers ---- yes i researched the marine railroad system , I believe there is no connection to cracks --- yes , i have boat insurance ( damage before taking delivery ) ---- No , i don't believe the original owner knew about the cracks

 

Typically a hole saw is used to take a laminate sample, it only takes a few minutes.

I'm not sure how you're going to get the original laminate schedule from the manufacturer though.

 

Two distinct issues here, a matter of legal liability for damage, and the repair to that damage, until the former is exhausted, or abandoned, the latter is on hold. After all, if it did end up resulting in a successful claim, it might not be your choice who repairs it, and how.

 

Whoa!!!! I'm new here so I apologize if I step on anyone's toes but I couldn't pass the opportunity to add my .02. I cannot for the life of me figure out how anyone would give a quote of $10k - $50. My previous role I was a composites engineer providing structural repairs for off wing composite commercial and corporate aviation parts and components, including wing leading edges, secondary flight control surfaces, engine cowls and just about everything else that can be damaged on a given airplane. I would personally perform repairs provided the legal data was in the manufacturer's structural repair manual and if not I would engineer the repair and submit them to the manufacturer for approval. I say all of this because during my years of doing this work i have rarely seen a repair exceed $50k and we used clean rooms with positive pressure, vacuum bagging, wet layups, resin infusion, prepreg, built molds and all kinds of fixtures. Sure im talking about airplanes and perhaps fiberglass boat repair facilities are tough to come by in canada but wow. The hull appears to be constructed with polyester resin and core mat?

I wouldn't consider Core Mat a "core" material. Core Mat is more of a bulking material, like a super thick fiberglass and you basically treat it as such. generally speaking it would and is very difficult for properly layed up fiberglass to delam. if it was done in one shoot, than it would have a chemical bond and be much less likely to have issues but if they laminated in stages, a mechanical bond would be created and have a greater chance of failure or trapped contaminants that would ultimately cause delam.

as for the damage, there is no way to know how bad it is until one would grind out all the damage and even if the damage ran the length of the hull, the repair would be just about the same as it would be if it were only a few inches (or mm's?). there could be all kinds of crazy cores or different materials that could change throughout the repair but for a production boat, i would be the bottom of the hull is consistent throughout.

no you do not need access to the back side even the backside is damaged provided one uses enginuity. i've repaired through hole pressure bulkheads without access to the backside pulling vacuum. if someone calls themself a fiberglass boat tech and says this is not possible then you need to take the boat elsewhere.

I would call this a bread and butter repair, easy money.
1. grind out all the damage. by doing this you'll get an idea of the layup schedule.
2. tapper the outside area to be repaired to accept new glass. for every layer of glass you grind through your repair area will expand 1 inch. so if you have a 1 inch circle hole in a part that has 3 layers of glass then your repair area will be a 2 inch diameter and therefore you will have two repair plys going back in. the first is a 1 inch circle patch and the next is a 2 inch circle patch.
3. if the damaged core mat is not to excessive then you should be able to use chopped mat to bulk up the area until your level with the first repair ply. other wise lay up the core mat just like you would with fiberglass and resin.
4. epoxy would be the prefered resin if your going to paint the hull but if the exterior is gel coat then you need to use vinyl ester or polyester resin.
5. sand the repair area, sand some more, keep sanding.
6. fill and fair the repair area.
7. sand the repair area, sand some more, keep sanding.
8. paint or gel coat and polish.

just by looking at the pictures I would give my self a couple days for the repair and maybe a couple more to finish. so for polyester maybe 5 days total and epoxy I would double that because epoxy takes far longer to cure.

im sure someone will disagree or add to my thoughts but at the end of the day to repair fiberglass its just a matter of putting back in what you took out.

I did a field repair on a wing flap for a big box stores corporate jet about 10 years ago this very way and it still looks great. although, I had heat lamps and vacuum bags, the repair including primer was complete in 10 hours.

good luck and sorry that this had to happen to you.

-Mark

 

You did catch the part that says he has two 12" cracks and 100" of delamination? That delam is a lot of trouble. And won't you need to use vacuum for the repair? It sounds more like several days of grinding than a few hours.

 

You’re correct, perhaps my estimate is a little high?

you’d be amazed at what 80 or even 40 grit sand paper can do in a shot amount of time with practice and patience.

Delamination repairs are even easier to repair than through damage. A delam will flake off as you sand or you can man handle it and rip it off by hand. Clean it up with 80 grit and taper the edges 1 inch out per each layer of glass that is removed and add your repair plys.

you can vacuum bag if you want to but that’s not really gonna add that much time to the overall job. Lay out the bagging tape, cut out your bleeder and breather cloth, wet out your laminations, apply, seal the bag and pull vacuum. Maybe a couple hours to set up and actually if it’s a wide open repair on the bottom of the hull it would most likely be easier and faster to vacuum bag than to wet layup.

If you don’t have experience with fiberglass, I would advise a hard pass on the job, however, as an outsider without any hands or eyes on the boat in person this is an easy job that should never cost anywhere near $50,000 in any currency.

 

The $50,000 is the walk away quote. That is the guy who thinks can o worms don't want it unless I make a mint.

I have done enough glass work to know that dimensionally grinding that down nice enough to take glass is several days of work laying in a haz suit. Shop rate of $150/hr is something like $2-3k to grind it out.

 

Ok so 2 days to grind out the damage, 2 days to layup the glass but only 1 actual day of work in total. Another 2 days for filler and sanding with only 1 day of actual hands on. 1 day to fill pinholes, seal , and prime and the last day to paint and buff. 5 or 6 days. So say maybe at your labor rate of $150 add $1500 for materials and we’re looking at close to $9,000, worst case an even $10,000? Although here in Tampa I know several shops that are less than $100 per hour and tons and tons of people doing work on the side for $30 or so an hour.

im still not sure though, you’re talking about 20 hours of just grinding and sanding the damage out? Considering this type of work was my job for several years, maybe I’ve become desensitized? Or maybe the boating industry doesn’t have much to rely on and therefore looks at repairs differently? Meaning before I could even put a finger on an airplane part I needed either engineering orders or manufacturers instructions to accomplish the repair. We never had to even consider that a repair was “good enough”, because they were always approved either by the FAA or the company who built the airplane. And I trust Boeing and the feds repairs a lot more than the guy at the marina. I don’t mean this to sound disrespectful at all. I mean, you learn that in composites anything can repaired and have equal strength but back into the part. At the end of the day the repairs are almost identical. Yeah, you have to pay attention to the fabric orientation and certain parts, your repairs cannot be stronger than the surrounding area as it would cause stress risers. You wouldn’t repair a fiberglass part with carbon fiber or a carbon part with Kevlar. Every repair I’ve ever done with composites, the cure time has taken far more time than actually working in the repair.

 

I dunno. You are the same guy complaining about $200 a sheet core. Maybe you are underselling repeatedly.

Now you are saying you can't make the area stronger. How do you profess to not do that wothout accessing the inside?

If the laminate is two layers of say db1700 glass exterior and coremat and two layers same inside; explain that one please. Are you going to do
jist go say 3 layers outside then and accept some concentration?

Of course cures take time. But that is time the boat is still on the shop floor.

I think the $10k number is about right. The materials for the repsir billout at say $500. I think about a week or two of real work. Taking apart the inside drives the price higher and there are some that would.

The guy doesn't live in Florida and there aren't a million backyard builders in and around London, Ont. billing out backyard rates.

The conversation has drifted into polemics which is the only place it could go.

Dave, have a surveyor look for evidence of a poor repair. If you can find the boat was repaired; it would have been a cover job and you can pretty easily pin the dealer in court. They sold you a boat that was not seaworthy.

Then, have the surveyor try to pin the cause of delam. It is probably mechanical bond failure related to the crack and a poor bond between the coremat and the skin.

Get the boat fixed. Call Noah's Marine in Toronto and talk with Ric Steves and see if he can recommend a good repair outfit.

Best of luck. The repair should cost somewhere between $10-20k. Depends if they decide to go inside and glass inside as well.

I am out of this thread.

good luck

 

Thank you , I will be doing one or two core hole saw cut outs . I have connections now to have them analyzed . I always like to plan for the high side of the repair range for those unexpected things you run into when the job starts . If it ends up being easier and cheaper ,that's a good thing . I think the key is having a good shop that will let you see , and explain the issues . I will find a shop i can trust , with a good reputation .

 

lol, polemics? im no upset. I apologize that someone has an opposing opinion to yours but this is the point of a public forum on the internet.

i'm trying to lay out the repair so the original poster doesn't get taken to the cleaners and just maybe if someone proposes a repair estimate of say $20k he can have an intelligent conversation with them to understand what and why they are charging so much. Considering the times we are currently in Ive noticed, at least in mom and pop automotive shops that their prices are skyrocketing. my guess is that people are driving less and the shops aren't getting as much work but still have to make the bills. if people are working less, then they are probably not boating as much and with the season over up there unfortunately the customer has to pay the price.

i digress, your quoting the guy $10K-$20K? thats a $10K difference. what are you expecting to eat up the $10K? Im only talking about the skin repair on the hull, no more than 6 days and nothing more than $10K and no need to go inside the cabin if there is no damage. you cant charge a customer cure times but im sure they charge a daily fee or something like that. and if they do charge the end user the hourly rate when no one is touching the boat than its time to consider taking the boat elsewhere.

this is all useful information for the OP to understand what he could be paying for. are you using epoxy? polyester? Core Mat? paint? gel coat? what other damage are you anticipating? the guys walking into a bill from $10K - $50K and i beleive between the two of us he should feel confident that anything over $20K could be ridiculous.

the first thing to do is grind out the damage to see the extent of it. if stringers are damaged than obviously were going inside but the only conceivable damage that i could see happening to the stringers is delam from the hull and this would really require cleaning up and tabbing them back in place.

as far as repairing without access to the backside. we would only need to repair the inside or backside if there was damage, agree? and there are many ways to do that. obviously, grind out the damage, now you'd have a through hole. lay up a and let cure a layer of fiberglass outside of the boat and cut it slightly larger than the hole on the inside of the skin. ensure that you have a slight lip on the inside and that your cured glass can fit into the hole. sort of like if you have a hole in your drywall, you need some backing to secure the drywall patch. mix up some filet epoxy and spread it on the inside of the lip (inside of the hull) and fit the cured fiberglass into the inside of the hull. now you just need to find a way to compress the cured glass to the epoxy. since its on the bottom of the boat you could attached screws or hot glue or CA glue something to the cured glass and maybe attached weight of some sort to the cured glass to sort of weigh it down. its difficult to explan but you basically making a backer that provides no structure to the boat and is only used as a solid surface to layup the repairs. add your structural glass and core mat and since you have a solid "backer" you can apply vacuum or just wet layup.

 

Did you make a claim against their insurance carrier?

 

Polemics, by definition, is a written attack on some portion of the subject matter or a person. In this issue, with no defined answers; people can go down any road they want. They can attack the repair shops, the dealer, the hauler, the manufacturer, the owner himself for buying no survey, the insurer of the dealer(good one Gonzo), or each other for said.

The thread has all the ingredients for polemics. Uncertainty is the best one.

Like I said, I am out, though.

 

Update . hull core cut out . Cut on edge of the large crack , close to the keel V . I am surprised at how thin it is . I thought it would be built up a bit at the V center point . Funny thing was , when you stick your finger inside toward Starboard , then thumb on outside and pinch - it feels a fair bit thicker . I can't see a separate core in the middle . There is a flat fiberglass panel , 2 '' above the cut out . I think it is a support panel for the waste tank . Only way to get tanks out of way is to cut the floor out or disassemble boat . -- Opinions ? I am working toward a repair this winter . Thanks