Advice please! Fiberglass boat hull hole patch (pics)

Hey guys i have a 15' fiberglass hull center console and i have recently discovered as i have removed my boat from the trailer to repair the bunker board brackets and such on the trailer that i had an extremely weak spot on the underside of the hull right where it sat on the end of the bunker board.

The spot was really weakened in this area and the fiberglass and paint was cracked in this area. Little did i know at the time but the crack is running alongside of a hidden stringer.

So i have decided to repair this area. Well i started out with a hole saw in an attempt to locate the hollow cavity between stringers and what do i do, drill right into the bottom of a stringer. Wow!!! Always some interesting facet of life popping up at weird times.



As you are able to see in the photo where the hole from the hole saw landed.

Also notice that this weak spot in the glass and the crack that i am going to repair runs right alongside the stringer <go figure>.

My question is do i need to cut approximately 3-4 inches on the other side of this stringer and remove this glass underneath this stringer so that i can eventually lay glass from one side of the stringer, underneath it and cover the entire area on this side cut now. All in one piece, one pass. ????



I plan on using some bi-axial cloth and create a hardened laminate piece to place above the inside of this hole and bond to this cut inner edges (3-4") along inside of hole.

Any suggestions? Advise greatly appreciated... Thanks a million guys.

Also i was thinking of using some of the west epoxy systems to repair this, i am somewhat concerned as to the size of the repair area and the strength that i need the hole to be repaired at.

I typically venture 8-10 miles from the boat ramp during fishing excursions fishing out in the coastal inland sounds and really need this patchwork to be stronger than the original area.

Tips, advice, your concerns are welcomed.

Chris

Re: Advice please! Fiberglass boat hull hole patch (pics)

Hey guys i have noticed through some readings that there are certain select types of epoxy resins which are used in the layout of a new boat make.

I guess the same type of resin type would have to be used in order to obtain a good chemical bond between the existing and the new. How would one go about detecting or attempting to detect the type of present epoxy system used in the creation of my boat's hull. HMMmm.

Re: Advice please! Fiberglass boat hull hole patch (pics)

There are no pleasure craft I know of that are made from epoxy. Its pretty much reserved for high performance boats due to the high expense.

99% sure your boat is polyester resin. Its cheap, works well, and will repair that hole.

BTW, I would open up the deck from above to lay glass from above and below.

Re: Advice please! Fiberglass boat hull hole patch (pics)

Wow....

First epoxy was used only in the higher end boats and not on 15' center consoles..... my bet is your boat is fiberglass BUT, I would go for an epoxy repair because...... it is much stronger.

Why did you cut open the hull? Too late now but it will have to be repaired from both sides. You will need to get under the decking to make the repair. What shape are the stringer's in? Are they damp or wet?

Re: Advice please! Fiberglass boat hull hole patch (pics)

My reasoning for cutting such a large hole was to get beyond all of the deep cracks in this area that was busted by the end of the bunker board and to repair not mend the area. Apparently from the boat perhaps bouncing one too many times on this area while in transit.

The reasoning for cutting the hole in the bottom was because i knew if i glassed over deep cracks and such it was only a matter of time before it would break my mat, water introduced and de-lamination occurred.

I was trying to prevent from tearing up such a great floor on the inside of my floor, extra sturdy and washes out excellent. was attempting not to disturb.

I am not sure at this point if the stringer is damp, it did appear to be in somewhat good condition. However as i investigate more thoroughly i will keep you guys posted.

WOW, my man says, you must have been stunned by the hole blown through the bottom here. Hey what do you do when knowledgeable contacts are limited you know?

YOU LIVE and you learn.

Anyways i am sure i'll get this patched up stronger than the original area was before. Just a matter of time.

Thanks, Chris

Re: Advice please! Fiberglass boat hull hole patch (pics)

Well i guess i will need to broaden the hole so that it passes to the other side of this stringer.

I will then open up floor in order to access the area and to be able to get a really good surface sand and clean for the laminate to be placed in this area.

I plan on creating a laminate of woven roven and allowing it to setup then use this to bond on the interior of the hole. My only area of concern is whereby it will run underneath the stringer here.

There could potentially be a small crack here as the material will not be able to be bonded to the interior of the topside of the hole due to having to pass under this stringer. Thinking as to how i can execute this repair so as to prevent this area of concern from ever 'cracking' later.

Thanks, Chris

Re: Advice please! Fiberglass boat hull hole patch (pics)

it should not to crack again unless the stringers are soft in that area. Bevel it properly on the outside and prep the inside well. Maybe relaminate over the old stinger and right onto your repaired area while all is still wet will make a nice bond and beef it up with some engineered wood to thickin it incase the stringer is iffy.

Re: Advice please! Fiberglass boat hull hole patch (pics)

Thanks my man that is exactly what i had in mine, was to beef it up. I plan on adding a piece of 2x4 in this area adjacent to the stringer but that got me wondering if i should really allow a piece to air dry and such really well prior to the install.

I am concerned with movement and such of the new piece installed that could potentially create some cracking in this new job.

What do you think?

I was planning on adding just a piece long enough to distribute the weight in this area, say approximately a 14-18" piece of 2x4 and wrapping the two together as i repair this area.

Open for concerns, other thoughts,

Thanks

Chris

Re: Advice please! Fiberglass boat hull hole patch (pics)

hey bud......just hold the phone a minit here....

you really need to stop and read a whole lot here.

you are really doing this repair wrong. (sorry about being negitave....but lets get you on the right track and get your boat fixed so you dont have any worries)

read the hull extension thread....especially when it comes to feathering the edge of the glass.

that is definately and inside out repair right now.
(that means you will have to repair it from the inside as well as the out side of the boat.....yep....you are cutting out some of the deck.

here are the basic steps...

1. STOP CUTTING YOUR HULL OPEN. STOP IT !

2. open the deck so you can get at both sides of the hull......

3. with a grinder feather the edge of the hole both inner and outer.

4 add a backing plate on the out side of that big hole you cut.....a smooth waxed formica peice will work.....if you must, cardboard wrapped in wax paper will do.

5 choose now what you are going to use, epoxy or poly....because what resin you use will determine the type of glass you need

(the following is for UNWAXED poly)

from the inside....

6. cut 2 pieces of thick fiberglass (1708) to the exact size of the hole...place in hole with backing plate the hairy side (matt) towards the backing plate. (this will re establish the approx thickness of your hull)
add layer of 1.oz csm over the 1708
cut the csm so it over laps the edge of the hole by 1 inch.

7. glass that all into place a layer at a time.

8. wait till it partially cures.....it will get hard....but you dont want to wait a few days. just wait about an hour till the next layer.

9. cut another layer of csm 2 inches larger than the last one and finally another large piece of 1708 to cover the entire area approx 4 inches larger than your largest layer.

10. glass that into place.....with the 1708...keep the matt side towards the area you are glassing over.....never have the cloth side touching the substraight.

11. wait an hour and pull off the waxed packing plate....

12 glass in a layer of csm over patched hole. cut the matt approx i inch larger than hole.

13 cut a larger piece of csm that will cover the entire area by at least 4 inches overlap,
at the same time cut an identical piece of finishing veil roving glass.

14. glass the last two pieces into place and let cure.

15 mix and add gellcoat paste to the fiberglassed area.

16. wait for a partial cure fair.

17...use a final coat of waxed gellcoat.

18....sand starting with 400 grit dry and work up to a 1500 grit using every grit in between.

19.....polish and wax.

there ya go.....

cheers
oops

Re: Advice please! Fiberglass boat hull hole patch (pics)

Appreciate Oops!

Thanks for your time in preparing this helpful composition of steps, for that i do appreciate.

I didn't really have any choice other than opening this area up, had a bad series of deepening cracks running alongside the stringer.

I realize that i was going to have to disturb my deck area, not wanting to but i knew that was the only way to repair a hole of this magnitude.

I still need some insight into whether or not i should fasten a sturdy piece of lumber adjacent to this stringer and glass over both of them at the same time. Concerned about movement and such with the addition of this new piece of lumber fastened as such.

Thanks, Chris

Also if you notice in the picture, i accidentally drilled directly underneath the stringer and my router bit wandered a little underneath the stringer as well. I was wanting to repair this without having to totally go on the other side of this stringer but with the cracked portions and such it leaves me with very little to bond to without doing so.

I was thinking that if i were to gain access to the other side of the stringer then i would have a really good bond on both sides of the hole, run this large piece of glass all the way under the stringer and it would be a significantly larger bond area then on the other side. ????

If repaired like this the only portion on this side of the hole would be to bond the glass onto the vertical edge of the stringer for there isn't sufficient work area on the hull bottom right here.

Please understand what i am trying to convey, it appears as if i am not doing a very good job of getting my inquire across to you guys.

If you need further please ask

Thanks, Chris

Re: Advice please! Fiberglass boat hull hole patch (pics)

feel free to call me.....you have the number chris.

fill the area under the stringer with peanut butter (read the hull thread for the meaning of peanut butter)

after you fix the hole in the above way you can add a piece of plywood on top of the repair area glass that to the hull so it is really stiff then add a triangle gusset from the stringer and glass that in .....that will do it....
the way the factory would repair that ....is to foam the boat with 2 part foam......this is a tremendous argument for foam.....it is structural.

if you want to add foam....add two small bulkheads between the deck and hull ....kinda a foam dam for when it expands.

do one to the other side because that area is weak too.....but DO NOT CUT THE HULL OPEN. you just have to re seal it....and as bad as it can get you can still fix it.

cheers
oops

Re: Advice please! Fiberglass boat hull hole patch (pics)

Yeah oops i plan on repairing the other side that rests on the bunker on that side of the trailer as well. AS you mentioned it is weak in that area as well if this side had so much damage.

But trust me, i will not go cutting through the hull on that side. I really like the idea of utilizing a triangular gusset to tie the plywood addition into the existing structure.

Hadn't thought of that, but oh boy, i know that will really beef things up in this area for sure. I quess i could use some 3/4 inch or would a little thinner suffice being i would be added the triangular support system. Plus the plywood wouldn't really cover a large area to demand really thick wood.

Thanks for your help thus far oops, i will dig into your thread and read up on all the pertinents involving peanut butter and such.

Thanks again, Chris

Re: Advice please! Fiberglass boat hull hole patch (pics)

1/2 inch ply will be fine....just glass it to the hull well
i was thinking .....when you cut the deck to do the repair from the inside.....you may as well cut a swath all the way to the other side and just replace the one peice of floor...(or for that matter....just keep the cut out and use that)

if you want help on how to repair the deck......just let me know bud.

cheers
oops

Re: Advice please! Fiberglass boat hull hole patch (pics)

oops i called myself looking for the appropriate mixture for the peanut butter mix found on your 'hull extension' thread, i am not sure if i had simply overlooked it or either did not search appropriately in order to locate that subject matter.

Could anyone give me a brief synopsis on the mixture ratios and such of structural peanut butter.

Also oops what weight woven roven would you use as the first initial base layer from the inside to cover this hole?

After that how many layers on the inside and of what weight / type need to be placed on this woven roven?

I have some Bondo-Glass that has short pieces of glass already mixed in the mixture and was curious to know if you have ever heard of it or used it? Wondering how it would do if utilized for the portion of the boat that will be underwater. Of course the boat is getting painted and this will all be covered.

Thanks, Chris

Re: Advice please! Fiberglass boat hull hole patch (pics)

hi chris.....

oops super dooper peanut butter...ingrediants & mixing....post # 1898 pg 76 of the hull extension thread.

forget woven roving.....get 1708 biax cloth.....the reason is that it has matt attached and the chance of messing up is a lot less......

if you cant find any around....(there is lots around you need to just open the phone book and look under fiberglass)
1 yard is more than enough....if you go to a boat glass shop they might even give you some scraps.

if you must use the woven...get as thick as you can....at least 25 oz material.
i would highly advise against using it untill you have glassed a few times.....if you use too big a cloth and too thin csm your bond could break because of the thick resin rich area between the lows of the woven and the csm.

the lay up schedule is in my first post.

and NO bondo ubder the water line.

the peanut butter is more than adequate it is structural

Re: Advice please! Fiberglass boat hull hole patch (pics)

Thanks oops for your feedback, i plan on utilizing the west epoxy systems epoxy for the mere fact i don't want any contraction of resin or such. I understand polyester resins can contract up to 6-8% of finished area and i definitely don't need that with this opening of up to 12" here.

So i have decided to utilize epoxy resins, now with that having been said, what type of 1708 biaxial mat is designed specifically for epoxy? As mentioned in your earlier post, there are specifics glass mats for various resins.

I have some time because i am actually awaiting the weather to cool some here in Eastern NC so i will not have to battle with super quick cure times and perhaps bonding failure. So i guess i will be awaiting a few more months before tackling the job, it's just too hot right now with 98 degree temps.

This should give me enough time to round up all the necessary materials for the job.

Thanks oops.

Chris

Re: Advice please! Fiberglass boat hull hole patch (pics)

There's nothing wrong with using epoxy, but if your decision was based on polyester possibly shrinking and creating problems, there's no need to worry about it. You're not going to have bonding problems at higher temps either, although it is easier to work with either type of resin at lower temps.

Re: Advice please! Fiberglass boat hull hole patch (pics)

if you use epoxy chris....(yes...it IS really good glue) do not use chopped strand matt......just use 17 oz biax cloth or thinner.

the epoxy does not contain styrene that the matt needs to break up the binders in the material.

cheers.
oops

Re: Advice please! Fiberglass boat hull hole patch (pics)

oops! said:

if you use epoxy chris....(yes...it IS really good glue) do not use chopped strand matt......just use 17 oz biax cloth or thinner.

the epoxy does not contain styrene that the matt needs to break up the binders in the material.

cheers.
oops

Click to expand...

Oops you mention biax cloth or thinner. Are you meaning some type of select thinner to utilize with the epoxy when applying to this 17 oz cloth?

I guess i could use this type of cloth for the entire patchup including the various size oval cut outs layered one on top of the other to fill in and cover this hole?

Gets me thinking what type of mat/cloth would i finish the area with on the underside (exterior) of the boat for the final lay.

Thanks, Chris

Re: Advice please! Fiberglass boat hull hole patch (pics)

arrrrgh ....dont have the time to answer it all...

thinner cloth than 17 oz....means 13 oz.

the 25 oz cloth...(1708) was to match the hull thickness.

we need to design you a new layup schedule with the epoxy only.

if ondarvr is on and sees this he can suggest one for you....mark 42?...jonesg?

ill be back on tonight chris...if no one has helped you ill give you a new schedule.....but just dont use csm ....and you cant use the thicker products on the seterior of the hull or you will have a permanant "bump" there that cannot be sanded out.

if you run into problems ...call me later