Gash in Fiberglass Keel - Quick Repair Option

[Gearhead62]

Fiberglass Veterans - These forums are the best - lots or experience and different perspectives

Please advise -

Just getting ideas here. I lean towards "aggressive / fast" vs "best way"....and I assume all risk. I've read several threads on fiberglass repair but can't seem to find one that addresses my situation. I am very mechanical, have all tools, but no glass experience

I just removed a 4-yr old sloppy resin / mat repair (from prev owner) on the keel of a 14' tri-hull Forester (early 70s?). This is my kids' boat - they have modified it for bowfishing at night and they're itching to get back on the water, given all the warm weather. Minimal investment ($200) in boat itself but it has a 5K Gen, 5 Halogens, supported by SpeedBar. mounting.

I have attached photos that show the damage - current state. It appears that repair was done from underneath? as there is resin slop on trailer below - likely from an auto store / glass repair kit.

I know that most will logically state you have to hit it from inside, removing deck, and then the outside, etc... and I agree with that - maybe next year. But I'm looking for a hack / workable method that allows a decent patch to be applied, fully aware that life expectancy will be lower than pro method.

After cleanup, appears I am into the original gash, can see wood stringer on the keel which is slightly damp - trying to remove whatever is bad. Yes - stringer(s) likely needs replacement. Glass adjacent to hole seems strong and on the linear ends of the crack I have found dry solid wood. I've heard of some wood restorer, heard about Marine-Tek, and a couple other tube items that might get me a season or two?

Please post any ideas - I assume all risk and know it should be done the right way, but the boat will likely be retired after I can squeeze a couple more seasons out of it until they upgrade - perfect for my young aspiring boaters / north suburban carp slayers.

Gonna step away for a few hours - Happy St Pat's to all.........Thanks in advance

 

[jigngrub]

Re: Gash in Fiberglass Keel - Quick Repair Option

A job well done goes hand in hand with peace of mind.

 

[Woodonglass]

Re: Gash in Fiberglass Keel - Quick Repair Option

You are correct that inside out is the way to go but...For a quick outside only fix, grind it back about 2-3" all around and feather to the middle so it's thin and valleyed out , mix up some thick structural PB (Resin, Cabosil and shredded pieces of csm) Consistency Thick peanut butter. Form the PB into the damage area and shape to the shape of the keel. this is just to hold the shape for the next step. Two layers of CSM, and layer of 1708 Biax and then two more layers of CSM. Sand and fair. Paint or Gelcoat. 2 hr job. Should take a major hit to break it loose. That's what I would do. The Pro's may come along and shoot me down but That's my methof of madness. I might try to use a string backer system if you know what that is but no bigger than it is you probably don't need it.

 

[oops!]

Re: Gash in Fiberglass Keel - Quick Repair Option

woodie has the fastest fix....

marine tex will pop out if the repair area is not covered.

the repair needs to have a few layers of glass over it.

just make sure you prep the area by grinding the gell coat off....that way you bond glass to glass...not glass to gellcoat

 

[Yacht Dr.]

Re: Gash in Fiberglass Keel - Quick Repair Option

I agree with Woody on his quick fix method.

When you get to the filling with PB you could try to pack sideways to kinda 'mushroom' the filler on the inside making a small rivet affect before you shape it for glass.

As far as how much glass you will need will be dependent on how thick the hull is. I would start with 1 layer of mat..then 1708..then just keep adding mat until its 'level'.

2,1,2 could be just right..or you might need one more/less mat.

Good thing for you is that the boat is flipped

Pop up some more pics when you have a chance.

YD.

 

[Gearhead62]

Re: Gash in Fiberglass Keel - Quick Repair Option

Great stuff...Thanks for all responses. I will get this going, post progress, results, along w/ pics

 

[Gearhead62]

Re: Gash in Fiberglass Keel - Quick Repair Option

That hull seems incredibly thin on the keel ridge - maybe just worn down with age?.......I plan to clean that gash better, get all the surrounding gel coat off, down to original fiberglass, feather back. I also plan scrape up inside behind the glass to achieve a void and pack it in for the mushroom effect - like that idea.

** Would it hurt to use the Marine Tek as the "mushroom" base, or do I stick w/ PB to fill? Is one preferred over the other for better adhesion?

As a final step, might be a candidate for a device similar to keel guard or $20 kevlar keel protector (canoe kit) for added protection?

 

[Woodonglass]

Re: Gash in Fiberglass Keel - Quick Repair Option

You said you were gunna try and do it the RIGHT way in the near future so I wouldn't worry about it. The method described will give you a lot of strength. If you want you can make a backer plate from a couple of layers of csm on wax paper. When it drys you can then drill a hole in the middle of it and put a string thru then place in the crack and then butter it up with some pb and use the string to pull it up tight to the inside of the hull. Hold it in place for 15 mins and it will be stuck in place as a backer. If you could use your finger to sand the inside of the hull and then a rag with acetone to wipe it down it would adhere very well and make the patch even stronger. I hope you understand what I am talking about.

 

[Gearhead62]

Re: Gash in Fiberglass Keel - Quick Repair Option

Yes - I understand the string backer method and required prep - Thanks....Just not sure when I wil completely "Do it Right" or do I just squeeze out a couple seasons - upgrade may be on the near horizon

 

[Woodonglass]

Re: Gash in Fiberglass Keel - Quick Repair Option

If you use the backer method and use 2-1-2 of CSM 1708 CSM it will last at least two seasons if not longer.

 

[oops!]

Re: Gash in Fiberglass Keel - Quick Repair Option

actually that backing method is one that could last a long long time.

the trick with that one is the bond to the glass on the inside.

sanding with your finger is the only way to get the top layer of flow coat off the old factory inner hull. the longer you take with this tedious and lousy step......the longer the backing plate will hold to the hull....

if you do a really good job of sanding....and cleaning with acetone.

a structural thickened resin could compound could last for years.

i have used this exact method for fixing thirty footers where there was just no way to get at the inside of the hull..

when you make the csm/1708 v'ed backing plate like woodie suggested..

......mix your filler, get it ready......then insert your backing plate....but suspend it above the hole.......now gob the filler into the hole...
and pull the string, so make the filler squish out of the space between the hull and the backing plate....but dont pull too hard that it all gishes out.....you want to leave some there to bond .

let cure....

grind out the excess filler that has gobbed thru the hole....just knock off the high spots....and start your laminating.

 

[Woodonglass]

Re: Gash in Fiberglass Keel - Quick Repair Option

Yep, that's exactly what I was talking about.

 

[Gearhead62]

Re: Gash in Fiberglass Keel - Quick Repair Option

I am going to attempt the backer method........A couple updates and questions:

I tapped and found some more weak glass keel sections from original gash towards the stern, so I extended the linear opening further and ground it a bit wider (for access). I need to point ou againt that directly under the gash is the old wood center stringer, originally glassed into the hull center / keel. I am removing some of the damp wood to get a void that will allow the backer to slip in. Also, I am seeing stronger thicker original glass as I remove wood - I'll try to snap a pic a bit later

I now have an opening that is 10" long and 0.5" wide. How deep should I go and how wide for effective prep? Do I need to prep that old wood stringer? Dry it our completely before Backer & PB? Other advice / questions?.................Thanks

 

[oops!]

Re: Gash in Fiberglass Keel - Quick Repair Option

dry the stringer as best you can.....then splash antifreeze on it....then let it dry some more.

the anti freeze will kill any rot fungus.

resin will not bond with anything wet.

im starting to worry about rotten stringers here with the wet center keel....

how long was this boat like this?

 

[Woodonglass]

Re: Gash in Fiberglass Keel - Quick Repair Option

Yes, I would attempt to dry it out as best you can. Heat gun, fans, etc... Since the Wood IS there this changes things a bit in my opinion. The wood will/can be your backer. I would mix up the structural PB and pack it into the voids as best as I could to fill it all up and let it "Goosh" (is that a word) out and build up to form the keel line as best as possible. I would then Grind/Sand to shape and lay the glass as previously discussed. The wood Keel Stringe will continue to rot, no doubt, but this should give you several more years of use.

 

[oops!]

Re: Gash in Fiberglass Keel - Quick Repair Option

i dont really think goosh is the correct term here woodie....

i think gish is more accurate.....lol

happy monday !

 

[Gearhead62]

Re: Gash in Fiberglass Keel - Quick Repair Option

Thanks gents

Not sure how long stringers were in this condition. My guess is that PO neglected it and didn't cover it from elements after original patch Since I have had posession, I've kept it dry / covered, but knew it would soon be an issue - here I am 3 years later. Not a wide boat - I think the center stringer might be the "only" stringer on this 14'?

As mentioned, I now have an opening that is 10" long. I have solid stringer under keel from inch 0-3 and from inch 7-10, so I have removed rot from 3-7, leaving room to work. I will be able to get in there to dry, sand and clean w/ acetone. I'll use a backer only from 3-7 and goosh entire length, using "good stringer" as backer where solid (0-3 and 7-10). We'll see what happens

 

[Woodonglass]

Re: Gash in Fiberglass Keel - Quick Repair Option

Sounds like you've got it under control. Post some pics of your progress.

 

[Gearhead62]

Re: Gash in Fiberglass Keel - Quick Repair Option

Not sure I'm under control yet, but I think I'm closing in - On my last post, rather than stating the plan, I should have asked if that method I described makes sense?

I rely on you guys for direction....Thanks

 

[BillP]

Re: Gash in Fiberglass Keel - Quick Repair Option

I wouldn't worry much about the glass sticking to the wood but if that matters use epoxy resin instead of poly. Otherwise, the way I'd fix this is cut all my cloth parts first, so you can do it in one session. Sand with 40 or 60 grit and tape around the area you want to glass. Wipe down generously with styrene to help create a chemical link...acetone and MEK don't. Cut 1.5oz (or 3 oz) csm strips to fit into the slot lengthwise, glass them in until they are flush with the bottom, then add a lengthwise csm patch approx 3" wider than the slot on each side. Alternate with 18oz (or 24oz) roven and another csm for the last layer. Last but not least, hit it with a hot resin coat to fill the cloth...if wanting to sand add wax in this coat. Basically it's ready to hit the water at this point but you can paint, gelcoat or apply pigmented resin for cosmetics without doing a wax coat to make it sandable. Don't worry about splashing tacky laminating resin (before flack comes my way from the other camp, I mean after the resin has fully cured), it doesn't hurt anything and the tack will go away. I've patched and splashed way to many trailer boats in the last XX yrs to think different (one happens to be sitting in my front yard and was done 10+ yrs ago). In my opinion a thin laminate is not desired in this particular application...which is what 1708 will give without extra layers, extra labor and extra $$$. Bulk is your friend or end up like what you are repairing again.

bp