Repair a hole in the bottom of the hull

[BassnKY]

I have a 1976 Bomber/Fiber King Marathon 15'.
I purchased this boat used about 6 years ago and have been SLOWLY (In between fishing) fixing it up.
A couple of years ago I replaced the carpet, remove the old "bell" style pedestal bases, and replaced them with the pin style seat pedestals by "SwivelEze". This spring, I completely rewired the boat, installed a switch panel, completely buffed out and resealed the paint, and installed a keel guard.
Unfortunately, a couple of weeks ago, as I was idling out of a creek arm at the lake and I hard a brain fart and got out of the channel. Needless to say, I got hung on a tree that had broken off just under the surface. I ended up with a nice 6" hole in the bottom.
I have some experience with fiberglass (and doing a little online research) and feel very comfortable doing the repair myself but have some questions:
1. What weight fiberglass cloth should I use? I am think 6 oz.
2. Can I use "general purpose" fiberglass resin or should it be an epoxy type?
3. The boat HAD some foam behind this area (It is not accessible from the inside). Can I use something like Tuff-Stuff to fill this area and as a backer for the patch? Is it compatible?
4. I don't believe this boat has a colored gel-coat finish so I am going to try and have the paint matched. While I am painting, I am going to re-paint the transom to cover up some old patches (dowels and marine epoxy) where previous owners had installed numerous transducer, etc... Is the marine paint compatible with the marine epoxy or will I need to coat it with resin first?

THANK YOU in advance for any help!!!!

 

[lowkee]

Re: Repair a hole in the bottom of the hull

Others with more experience may chime in on this, but I'll give it a go until they do.

You'll want biax and mat to patch the hole. 1708 is the name of it. You can use just mat in a pinch. 8oz cloth is much too light for a hole patch and cloth alone leaves resin gaps which are weak. Poly is fine for a patch, but make sure you scuff it up nicely.

Now for the bad news, this needs to be done from the inside. Consider the following.. you sand around the hole, patch with 3-4 layers of mat (~1/8 inch), then sand it down for painting.. by the time you sand it flush, the patch will fall off, as you just sanded off the overlapping portions in order to make it flush with the rest of the hull. You can't exactly sand away 1/8" around the hole to account for tabbing it on, as you would sand right through the hull. If you are okay leaving the patch as a blob on your hull, you may get away with doing it from the outside, but I'll likely be flogged for even saying that.

 

[Yacht Dr.]

Re: Repair a hole in the bottom of the hull

Hello Bass..

You really should do an inside few lams .. If at all possible cut some foam out at the edge of the repair inside ( a bent thrift store bread knife would do the trick ) then pack that with some glass. doesnt have to be pretty .. feather your outside a bit larger then the norm ( try 3" around your repair ) .. Oh yea..in this case I would use epoxy. glass with 1708. sand,prep and paint.

you can use foam to build an inside ( low ) backing..just lightly coat a piece of mat and resin over it until cured before you start your lams ( lam when curing has started and go like the wind )

Good luck..

YD.

PS. Im now on my 4th week on location site working .. sorry for delays. the Wifi is scattery at best here..(and this coming week im going on vacation ).

 

[BassnKY]

Re: Repair a hole in the bottom of the hull

Sorry for the delay getting back on line.

What I was going to try to do was laminate a patch (2-3 layer) slightly larger than the hole after I get rid of anything surrounding the hole were the existing lamination of fiberglass separated. Then, use a grinder to form a 12:1 (Min) bevel around the hole. (This works great from past experience.)

At this point, I would drill a hole in it and resin the patch on the inside (It should be flexible enough.) After the interior patch had cured, I thought that filling the cavity (Through the hole.) would give it a more solid backing.

In my research on line, I discovered that when I laminate up the exterior patch, in progressively smaller layer, the largest patch should go TOWARD the hole when it is resined into position.

I do not want to have a big hump on the bottom and the where the hole is located, it would be a MAJOR MAJOR ordeal to get to it from the inside.

Thank YOU to everyone for the input!!!

 

[oops!]

Re: Repair a hole in the bottom of the hull

hi bud.......sorry....it is an inside out job.

that means it nust be repaired from the inside or you will get the massive bump.

the gellcoat is only 35 thou thick.....so to laminate the glass at 1/8 th inch for a layer of 1.5 oz matt alone....there is a bump.

you gotta dig into it from the inside if you dont want the bump.

the standard practice is to start with the biggest layer of glass first.
i personally am the oppisite way.....i start with the smallest peice first....that way if the bond fails on the one peice of glass, the next larger will still have a bond and support it.......a lot of old time glassers do not like my method for lots of reasons.....however, this is a small patch.....duct tape will work for a little while.

but......it really needs to be done from the inside.....remember if you use poly resin......(no need really to use epoxy)....the chopped strand matt needs to go down first....then cloth.....but unless you are using a bi ax....a 6 oz finishing veil will have no structural stregnth to the repair....you can add some cloth veil betewwn layers of the matt.....but that is just to reinforce the matt.

i just saw a huge hole in a new jet boat (on the bottom just before the transom) repaired from the inside out....and finished like it was new in just 2 days work.

so its just your time.....yep its more work to do it inside out.....but it is the only way to do it right with out the bump.

cheers
oops

 

[Rickairmedic]

Re: Repair a hole in the bottom of the hull

Bassn I cant help you with the repair other than if Ooops says to do it a certain way thats the way to do it he is the Glass master here . What part of Louisville are you in nd where re you running your boat at.


Rick

 

[Rickairmedic]

Re: Repair a hole in the bottom of the hull

Bassn I will offer up a neighborly place to work on the repairs if you dont have the tools to do it . I own n HVAC company so if theres a tool I probably have 2 or 3 of them .


Rick

 

[Yacht Dr.]

Re: Repair a hole in the bottom of the hull

Hello again..

I as well would recommend layups of smallest first and largest last.. ( multiple failure points as Oops is saying ) .. basically if you do your largest lam first.. it has one lam of failure of the whole repair..as where doing it small to large has multiple lam failure points ... if you know what we are saying...

YD.

 

[BassnKY]

Re: Repair a hole in the bottom of the hull

ooops:
Thank you for the info. I have read many of your post and you really seem to know what you are talking about.
Do have any suggestion on getting to the hole. It is directly under the driver's seat. Am I going to have to take the top section of the boat off. Then I would have to get through the floor board. Would it help if I could get some pic's tomorrow?
Also, do I need to bevel the hole on the inside?

Rickairmedic:
I sent you a private message.

 

[Rickairmedic]

Re: Repair a hole in the bottom of the hull

Bass I would cut a hole in the deck big enough to work through . I would cut it with an angle so that after done making the repair you could reinforce the edges of the hole from underneath and then gladd the hole in the Deck back in . The actual repair is more Oooop's and Yaght Dr's area although I have 2 glass boats my current resto is aluminum .



PM'd ya back

Rick

 

[BassnKY]

Re: Repair a hole in the bottom of the hull

oops:

Just wanted to give you a little background on my experience and let you know where I found the info on the positioning of the layers.

I do have quite a bit of experience in working with fiberglass but it has been quite a while. YEARS (25+) ago I did quite a bit of bodywork both on the side and in a shop my brother in-law owned. Sometimes, this included repairing fiberglass parts and even fabricating new ones. Whenever I had a hole to fill, I used the bevel method, and stacked the layers as you had suggested, on the outside and was taught that you did this so if someone hit or leaned against the repair spot, it would be pushing the repair into the remaining good fiberglass. I do realize that a car and a boat are different so that is why I am asking the questions I am.

Also, here is where I found the info on the:
http://www.youtube.com/watch?v=i97TlAdenv4

Also, my memory is a little rusty so you might have to explain some of the terminology.

Thank You again for your help!!!

 

[BassnKY]

Re: Repair a hole in the bottom of the hull

Yacht Dr:
Thank You for your input. I do understand your point. Makes sense to me!
Please read my last post. It will give you some insight into my experience.
Bassn

 

[109jb]

Re: Repair a hole in the bottom of the hull

Years ago a friend of mine fixed a hole in his fiberglass boat and did an inside out repair, but did everything through an oval shaped hole from the outside without cutting a hole in his deck. From what I remember he used the following steps.

1. first cut an oval shaped hole from the outside (from what I remember he made a hole about 2" in the short direction and 4 inches in the long.)
2. Made a 1/4" plywood about 1" larger than the ovel all the way around with a screw in the middle for a handle..
3. cleaned out enough foam to be able to insert the plywood and get it into position inside the hull.
4. sanded the backside of the hole with coarse sandpaper
5. layed up CSM on the plywood and positioned in hole on inside of hull.
6. Used another piece of plywood with plastic tape on it as a release on the outside of the hull and screwed the 2 pieces of plywood together sandwiching the hull between them.
7. Let cure and then removed screws and outer plywood
8. Did outside layups like normal.

The hole in my buddies boat was down low where the foam was thick and would have meant a big hole in the deck and a lot of foam removal from inside which is why he did the repair that way. My friend had that boat for at least another 10 years and never had a roblem with that repair.

 

[BassnKY]

Re: Repair a hole in the bottom of the hull

109jb:
Thank You for the response. That sounds like a good idea.

However, upon further investigation, the hole lines up with the driver's seat so I might be able to get to it that way. If I remove the seat, I should be able to cut a hole in the floorboard and gain access with a starter hole and reciprocating saw.

Afterward, I can glass back in the the panel I cut out. I do not want to leave it open as it would leave easy access for water should the patch fail.

I do have a few more Q's:
1. After I get the hole patched, can I use something like Tuff-Stuff to replace the foam.
2. Should I go ahead and bevel the outside and glass in (2-3 Layer) until I can use resin and micro-balloons (extender) to bring it even with the surrounding surface? I feel like this would make it even stronger.
3. Once I glass over the hole on the inside, what is the best way to fill the hole? It will be about 1/4" deep.

ooops:

1. Is chopped strand mat the same as non-directional?
2. Does bi-ax cloth you mentioned come in different weights.
3. I read you response to mean all the layers should be the bi-ax. Is this correct?
4. How many layers should I use? My first inclination is 3-4.

Here are some pic's I took this morning.


View from the front


Closer view from the front.

Close up (Kind of blurry).




The safety lanyard and duct tape show the location of the hole in relation to the top side.

I couldn't figure out how to insert the pic's without using the thumbnails.


THANK YOU again everyone!!!

 

[Rickairmedic]

Re: Repair a hole in the bottom of the hull

Thats a pretty hole . There is damage beyond the hole as well so you are going to have some good sized patches to work with . I would definately go in under the drivers seat and bevel the opening like you are planning . I would also bevel the hole from the inside and outside and do the inside patch first well past the hole and then go from outside . I will let Ooops give the specifics since he is the Glass guru around here .


Rick

 

[BassnKY]

Re: Repair a hole in the bottom of the hull

rickairmedic:

I think I got lucky (If you can call it luck) with the location of the hole. I did not realize it until I went to take pic's. I guess I was too disgusted with it when I got home to look too close.

Yes, it is pretty I guess! I will definitely take a close look at the 2 sides when I get it opened up. With the left side being that close to the step in the hull, I want to make sure there is no hidden damage.

It's hard to believe I fished another 2 hours AND watched the weigh-in AFTER I got the hole in it!!

 

[Rickairmedic]

Re: Repair a hole in the bottom of the hull

LOL yeah I gotta agree with a hole that big thats pretty impresive that you were able to stay out that much longer . Where were you running when you did it . I plan to run mostly in the Ohio .


Rick

 

[BassnKY]

Re: Repair a hole in the bottom of the hull

Rickairmedic:
I was actually idling out of a cove @ Taylorsville Lake. I wasn't paying attention (Brain fart) and got out of the channel. I used to do this all the time during tournaments because time could be money. (I enjoy the competition). I will not be doing that again. After about an hour, I notice the carpet was getting damp.
I have never had it out on the river (Too far to run to find fish) but the guy I bought it from lived on the river and did all the time.

 

[Rickairmedic]

Re: Repair a hole in the bottom of the hull

LOL I dont really fish other than deep sea so I dont worry about chasing them . I am about 2 miles from the greenwood ramp so thats where I will be putting in most of the time once I get the current resto done .



Rick

 

[BassnKY]

Re: Repair a hole in the bottom of the hull

Rick:
Checked out your post.
Your boat is sure looking GOOD. When do you think you will get it done and be on the water?