# Fiberglass repatch



## BenJam (Nov 14, 2020)

I have a 2005 15' flats skiff (Sea Island. Now similar to a MiTide) that was given to me.







Noticed recently that water was entering the hull and flowing into the transom well, which led me to a crack in the bottom of the hull, about 2ft from the back of the boat. Started cleaning up the crack and realized it was previously patched. I've cut out the old crack in it's entirety and sanded a bevel out to about 2" (the hull thickness is 1/8"). See picture. Crack is about a foot long.







Was planning on patching with successively smaller 6oz fiberglass and polyester resin. The foam above the crack seems to be in good condition. Above the crack is the livewell, so I would have to cut into the live well AND the deck and the foam to get to the crack from above. Obviously I would like to avoid that If possible. So, my question(s) before I begin patching:

Does this seem like the correct approach? Correct glass weight and bevel dimensions etc. 
Anything special to do considering this is an old patch?
Is there any way to tell if the old patch was done in epoxy or poly? If I am going to repatch, I need to match the material right?
Assuming I can't tell, it would be best to patch in epoxy right? But then the gelcoat won't bond as well. So maybe epoxy and some other top coat.
Any and all input is much appreciated.


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## DuckNut (Apr 3, 2009)

BenJam said:


> successively smaller 6oz fiberglass and polyester resin.


Successively LARGER 6 oz fiberglass and EPOXY.

You got the process down.

My big concern is that you must get all the water out before you seal it up. I really can't tell you how without seeing the boat in person but do your absolute best to ensure it is dry between the hull and the liner. Once you think you got it dry, repeat your process again and then patch.


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## Hightide03 (Nov 7, 2019)

I have this same hull and have also had this same repair done. You may want to drill an access port topside to check the foam for saturation. Does it sit a little lower in the stern than you think it should? My stringers ended up turning black because water was trapped inside the hull and found its way forward. I am in the process of re-building my floor right now.


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## DuckNut (Apr 3, 2009)

Hightide03 said:


> I have this same hull and have also had this same repair done. You may want to drill an access port topside to check the foam for saturation. Does it sit a little lower in the stern than you think it should? My stringers ended up turning black because water was trapped inside the hull and found its way forward. I am in the process of re-building my floor right now.


The interior of the stringer (let's say its wood) is only there as a form to build glass around. The glass is the stringer, not what is in the middle of it.

There is a high profile super go fast boat company that uses wood to form the stringers. They lay the glass on the outside of the wood forms and before capping it they remove the wood and leave the cavity hollow. This is on boats that go way over 100mph.


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## Hightide03 (Nov 7, 2019)

DuckNut said:


> The interior of the stringer (let's say its wood) is only there as a form to build glass around. The glass is the stringer, not what is in the middle of it.
> 
> There is a high profile super go fast boat company that uses wood to form the stringers. They lay the glass on the outside of the wood forms and before capping it they remove the wood and leave the cavity hollow. This is on boats that go way over 100mph.


Yes, my stringers were glassed. Unfortunately they de-laminated in a few areas and the wood became saturated with saltwater for months. They are still solid for the most part but while I am re-doing the floor I might as well replace the stringers with composite materials.


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## Hightide03 (Nov 7, 2019)

You can see the inspection port I drilled in the first picture. That foam was completely soaked. In the second you can see where I tried to patch the hull years prior.


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## BenJam (Nov 14, 2020)

DuckNut said:


> Successively LARGER 6 oz fiberglass and EPOXY.
> 
> You got the process down.
> 
> My big concern is that you must get all the water out before you seal it up. I really can't tell you how without seeing the boat in person but do your absolute best to ensure it is dry between the hull and the liner. Once you think you got it dry, repeat your process again and then patch.


Nice, thanks for that clarification of the order of the cloth pieces. As for drying, I've got the boat inclined for drainage out the back, been that way for about a week. Foam and laminate seem dry to me, but I'll keep it drying for a few more days just to make sure. Dry winter air should help with that. However, this hull has a drainage hole from the inner hull to the back transom well (that's how I noticed the leak in the first place, water was coming in through the hull crack and flowing out into the transom well). So, water can still get into the hull through the reverse process, collecting in the well and then flowing into the hull through the drainage hole. I imagine this was part of the design, but it seems a lot of people are worried about getting the foam wet and waterlogged, so not sure how to avoid that without plugging that drainage hole. I'll assume the foam is closed cell and can get wet by design, but make sure everything is dry for that actual patching process. 



Thanks again DuckNut


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## BenJam (Nov 14, 2020)

Hightide03 said:


> I have this same hull and have also had this same repair done. You may want to drill an access port topside to check the foam for saturation. Does it sit a little lower in the stern than you think it should? My stringers ended up turning black because water was trapped inside the hull and found its way forward. I am in the process of re-building my floor right now.


Thanks for that, I've heard this concern before. My hull seems a little different than what you posted, but point taken. As I responded to DuckNut, the hull has a built in drainage hole from the hull interior to the splash well in the transom, so it seems like it was designed to allow water to flow from the hull interior to the well (and vice-a-versa). I'll keep this foam waterlogging issue in mind though, thanks.


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## Hightide03 (Nov 7, 2019)

BenJam said:


> Thanks for that, I've heard this concern before. My hull seems a little different than what you posted, but point taken. As I responded to DuckNut, the hull has a built in drainage hole from the hull interior to the splash well in the transom, so it seems like it was designed to allow water to flow from the hull interior to the well (and vice-a-versa). I'll keep this foam waterlogging issue in mind though, thanks.


The Sea Island skiffs were made for a couple of years in Awendaw, SC from the same mold as the High Tide Super V 1503. The major difference is the fore and aft deck on yours vs the bench set-up on the High Tide. Interesting about the drainage hole... I wonder if the builder even used foam under the floor. If he did, maybe it is compartmentalized between stringers and stiffeners and hopefully it is closed-cell. Just keep drying it out like you are doing and seal it up when you feel confident there is no more moisture!


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## permitchaser (Aug 26, 2013)

This reminds me of when I was restoring. My boat had a large has tank glassed in (removed) there was a high drain at the top of the has tank the went to the bilge. Under my floor and under my console is foam. So I plugged up all drains including the one on the floor under the deck that was soaking foam. If any water gets in I use my wet vac and a fan


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## Capnredfish (Feb 1, 2012)

Reverse layup. Start small and go bigger as you build out. That way all layers of laminate make contact with original hull around the perimeter


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## BenJam (Nov 14, 2020)

Thanks y'all, feeling better about this but now thinking long and hard about doing an upside down repatch...not sure how well the soaked glass will stick to the underside of the hull. Flipping the boat would prob be best but not sure I have the proper tools/support to do so. Best I can think is to let the resin kick a little bit before placing the glass, maybe that will hold better. Or somehow using tape to hold the soaked glass is place while it cures.


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## DuckNut (Apr 3, 2009)

Tape down a thick trash bag onto a work bench - pull it tight. Put your glass on that and wet it out then pick it up and put it in place and then smooth out the air. It will be a mess if you try to wet it out on the hull.


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## lemaymiami (Feb 9, 2007)

We always used a piece of cardboard to be able to wet out materials before transferring them to the repair site... Very handy.


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## DuckNut (Apr 3, 2009)

lemaymiami said:


> We always used a piece of cardboard to be able to wet out materials before transferring them to the repair site... Very handy.


I've had some bad experience with cardboard. Seems that there are parts of the mix that are absorbed into the cardboard quicker than others, leaving an inconsistent mix.


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## Gogittum (May 24, 2020)

Not sure if I'm missing something in translation here. An older boat I bought some years ago had a thru hull transducer that was leaking and was far obsolete, so I removed it.....which left a 1" hole in the hull. I worked with System 3 epoxy and they were very helpful and very specific on how to go about it. I won't try to address the soaking/water issue, that's outside my experience, but here's what System 3 taught me - and it was rock solid......








Grind an 8:1 taper on the outside of the hull. Start with a large piece of 6 or 8 oz cloth and wet it out on a sheet of plastic, then pick it up and apply it to the hull. (pre-wet the hull with resin 1st) I found that a baker's plastic squeegee - about 4" x 5" - that they use for scraping dough out of a mixer bowl works very well to squeegee the glass to the hull and get bubbles and excess resin out - use the curved side and be very gentle - the patch will try to bunch and slide. Cut a slightly smaller piece and repeat, then a smaller piece yet and repeat. It's been quite a few years, but IIRC, I think I used 10 layers of 6 oz. Yes, it Is tedious and messy and will take a while. It may help to let each layer stiffen up a bit before applying the next. It wasn't possible for me to roll the boat - had to do it underneath, which required some care, but worked well.

The thing with this is that you're getting full thickness of each layer on the patch. When fully cured and you fair it in, you'll be grinding off the ends of the patches and leaving full thickness on the hull. When done fairing, fill the remaining hollow in the middle with thickened epoxy - I used chopped fiber for strength.

If you put the smaller patches on 1st and go larger, there's a very real possibility that you'll be cutting into the body of the patch when fairing - patches can actually form a dome shape....which might work OK, but will be some weaker, too. Shortly after doing this patch and before it was even painted, I was on plane and hit a large chunk of driftwood with a huge thump. When back on the trailer, I looked and the scuff mark was directly on the center of the patch. Yup, it were plenty strong. This was on an older 19 ft Glastron runabout.


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## BenJam (Nov 14, 2020)

Gogittum said:


> Not sure if I'm missing something in translation here. An older boat I bought some years ago had a thru hull transducer that was leaking and was far obsolete, so I removed it.....which left a 1" hole in the hull. I worked with System 3 epoxy and they were very helpful and very specific on how to go about it. I won't try to address the soaking/water issue, that's outside my experience, but here's what System 3 taught me - and it was rock solid......
> View attachment 160243
> 
> Grind an 8:1 taper on the outside of the hull. Start with a large piece of 6 or 8 oz cloth and wet it out on a sheet of plastic, then pick it up and apply it to the hull. (pre-wet the hull with resin 1st) I found that a baker's plastic squeegee - about 4" x 5" - that they use for scraping dough out of a mixer bowl works very well to squeegee the glass to the hull and get bubbles and excess resin out - use the curved side and be very gentle - the patch will try to bunch and slide. Cut a slightly smaller piece and repeat, then a smaller piece yet and repeat. It's been quite a few years, but IIRC, I think I used 10 layers of 6 oz. Yes, it Is tedious and messy and will take a while. It may help to let each layer stiffen up a bit before applying the next. It wasn't possible for me to roll the boat - had to do it underneath, which required some care, but worked well.
> ...


Dang, nice example, thanks for the that. Seems there are some conflicting opinions about the order of the glass pieces. I've read my fair share of pros and cons for each, still not sure what I'll end up doing. I don't really see how the order changes the possibility of cutting/sanding into the patch, I feel like that's gonna happen either way no matter what.


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## Gogittum (May 24, 2020)

Just like something else - everyone's got one. FWIW, here's how System 3 explained it to me:









If you do as I showed, the layers tend to dish into the patch area, so when you sand it smooth you're just taking off the edges of the cloth, then fill the hollow with thickened epoxy if desired. All layers of the patch are intact.









I exaggerated this to make a point - when starting with the small patches at the bottom, they'll tend to bulge upward with the epoxy between the layers, so when you sand it, you could be taking layers of the patch off and finished patch will have fewer effective layers. 

That's my story and I'm sticking to it. Do as you will.


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## BenJam (Nov 14, 2020)

I see, I actually didn't even notice your diagram in the first post was a demonstration of your point. I thought it was some sort of artsy design thing.

Anyways, I see your point here and it seems to make sense. Thanks again.


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## Gogittum (May 24, 2020)

Noodling about this in the half asleep/half awake zone before getting up this morning, I remembered something from a later repair on....something....don't even remember what, but anyway......

"If" you hit it with the patch almost fully cured, where it's very firm but not rock hard yet, you can take a wide, very sharp chisel and go after the edge of the patch with a slicing motion with chisel bevel held flat to hull. The 3/4 cured 'glass will slice like cheese and make your final sanding much, much quicker and easier. 

Hit it a bit too soon and the patch will flex and pull away and will need to be re-repaired. Too late and it won't cut - too hard. Maybe make a practice piece while doing the repair ?? Both would be cured equally - when practice piece slices nicely, go for the patch.....or just wait for it to fully cure and sand as usual.  Good Luck.


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## BenJam (Nov 14, 2020)

Update, just finished reglassing this hole. This is what I ended up doing.

Got a West System 105-k epoxy repair kit from Amazon. Seems like a good deal to me. Probably not the best bang for your buck, but it's convenient with a variety of tools and materials needed for different jobs. 10oz cloth, epoxy and hardner in pre-measured packets, as well as brushes, gloves, fairing material etc. Also a little instruction sheet for different jobs.

Sanded out the bevel around the hole, about 1.5" wide all around, and let everything dry out for a week (wasnt wet, just a precaution). Cleaned everything up with acetone.

I was worried about the new patch sticking to the foam on the other side of the hole. I thought this might create another force on the patch, with the foam pulling on it from the inside. Plus, the foam isn't supposed to be bonded to the hull, so I wanted to avoid that. To do so, I shoved a piece of plastic shopping bag into the hole, basically creating a barrier between the foam and the new epoxy patch.

The total area of the bevel was about 15" x 3.5", or about 50 square inches, which is just about the amount of glass a packet of resin from the kit can soak. I precut 4 pieces of glass, the smallest one overlapped the hole by about 0.25" and each one after was about 0.5" larger than the previous one. I mixed three packets of resin and hardner. I then painted a layer of epoxy on the bevel area of the hull, not too worried about going over the bevel area, can always sand down later. I separated about a quarter to a third of the remaining mixture and mixed it in with some cut up and shredded glass. This mixture I applied directly to the hole as a means of filling that void and strengthening the bridge. I then layed the smallest glass piece on some cleaned plastic and brushed on the epoxy mix. I then did the same for the other pieces, laying each one centered on top of the previous one. I made sure each piece was fully wetted by the epoxy. Then I lifted the whole thing off the plastic and applied it directly to the hull, smallest piece down. This contradicted the instructions from the kit and @Gogittum from this thread, but others have said it's the way to go, so that's what I did.

I was anticipating the patch constantly trying to drop off the hull, but it didn't. Maybe because I had pre wet the hull and applied the glass mixture first, I don't know why but it stuck fine from the beginning. I used a cheap sponge on a stick from the painting section at the hardware store and just worked over the patch, pressing down and trying to squeeze out air and excess resin. I pulled a little around the edges to stretch it out and make sure it didn't sink too much into the hull. Because of the foam and the glass mixture I applied before, the patch didn't sink too much into the hole.

After about 20-30 minutes of this I mixed another packet of resin and about 75% of the fairing powder until it was a thick consistency and applied all of it to the patch, smoothing it out over the area. It seemed to fall in mostly over the hole, which I took as a good sign that it was smoothing out over the glass that sunk into the hole.

That's where I'm at. 7 hours later, the patch seems cured and ready to sand but I haven't done that yet. I will eventually sand it down, mostly along the edge of the patch to bring it back to the rest of the hull, then I will clean and apply some True Boat gelcoat with wax.


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## DuckNut (Apr 3, 2009)

That is the way to get the job done. Most importantly - don't overthink the process.


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