Got a Hole in the most aft water ballast tank...

[phyrefighterjay]

Well we knew what we were getting into....I am a new mac owner (96 26x) And I bought that mac that got rolled in the last hurricane to kiss Texas.
The boat got pushed and set on a piling that made an oval shaped hole approx 1 foot by 10 inches. This hole is just starboard of the midline keel and almost perfectly centered in the middle of the rear ballast tank (thank god). So...anyone ever patched a hole this big? I know It is doable, but what kind of forces (torsional etc.) will this area have on it? Given that there is a molded tank surrounding it, I figure there is quite a bit of support. What type of reinforcements can I make (since I can only work from the outside hull)?
Much Thanks from a new mac owner!!!
JAson Wilhelm

[Pete]

Youtube West System Epoxy. They have severial videos on how to repair such a hole with access from only one side. Get some pictures.

Pete

[SkiDeep2001]

Here's the link for West Systems http://tr.youtube.com/watch?v=8GQxtaqlA ... B9&index=0

[LOUIS B HOLUB]

Damage the size you've described ought to have "professional" repair. I would suggest some experienced help, with professional advice. Being on the safe side would be my thinking...after all...this is below the water line and I would assume as a high stress area.
Good Luck. Hope you get this done soon...the season is here.

Happy Sailing.

[kmclemore]

I agree on getting professional help, but if a I were to tackle it here's what I'd do....

- Clean up the damage - cut/grind back the fiberglass to the end of any localized stress cracks. Do not leave any square corners - radius everything.

- Fair the edges back such that it looks like this: \__/ ... only the faired area should be at a much borader "v" than that... providing basically about a 1-2" band around the entire area to allow for bonding a new section in.

- Away from the boat, make up a fiberglass panel large enough to extend as far beyond the edges of the injury as possible whilst still being able to insert it in the hole (use a piece of cardboard to make a pattern for trial fitting), and make it at least 4-5 layers of fiberglass thick... if it needs to be curved, make sure you create the panel over a pattern (shaped cardboard covered with waxed paper works well for this). Use coarse rovings rather than thinner cloth to create the panel if they are available. Allow this panel to harden, then trim any ragged edges.

- Use a wire fishing tape to fish a piece of string from the ballast drain in the back of the boat up to the damaged area. Secure the aft part of the string to the drain handle.

- Inflate a balloon just enough such that when it is placed against the bottom of the hole it rises to a point slightly higher than the damaged area. Tie the string to the balloon and let it hang out of the hole.

- Make up some marine epoxy and apply it to the inside edge of the hole and the outside edge of the fiberglass panel you made.

- Insert the balloon in the hole. A small rolled bit of tape on the back of the balloon may be necessary to hold it in the hole.

- Now carefully maneuver the panel into the hole. Since your hole is larger one way than the other you'll use an insert-and-turn method here. You'll need to depress the balloon gently as you insert the panel, but if you've inflated it properly it should just be large enough to hold the panel in place with moderate pressure.

- Once the panel is in position let it dry for 24 hours while the balloon holds it up against the outer hull.

- Once the panel is fully hardened against the hull, take your smallest drill and drill a tiny hole in the center of the panel... this will pop the balloon. Remove most of the balloon using the string attached to the drain (any remaining bits will eventually be flushed out over time).

- Now lay up the outside of the hull using rovings at first and then using thinner cloth as you get to the top.

- Sand where necessary once hard.

- Finish with white gel coat, but be sure to cover the gel with saran wrap to ensure full hardening of the surface. Remember to apply enough gel to allow sanding down... the gel should initially be slightly proud of the original surface.

- Once the gel is fully hardened (I usually wait several days), wet-sand flat to the surrounding surface using a block.

- Buff and wax.

[Hardcrab]

Pretty slick.
The hole to pop the ballon might not be needed.
With time, the ballon will leak out most all the air, then be flushed out the back one day.

The unknown will be any direct pounding the hull receives while up on plane.
This area is what's taking the loads at speed.

Could it be worth it to cut an access hole in the top of the tank to insure a known good hull patch, then cover the hole back up?
At least a tank upper hole won't see the possible pounding the hull might see.

[phyrefighterjay]

With your help, I'm going to start the repair tomorrow. Thanks again

[kmclemore]

Pretty slick.
The hole to pop the ballon might not be needed. With time, the ballon will leak out most all the air, then be flushed out the back one day.

The unknown will be any direct pounding the hull receives while up on plane.
This area is what's taking the loads at speed.

Could it be worth it to cut an access hole in the top of the tank to insure a known good hull patch, then cover the hole back up? At least a tank upper hole won't see the possible pounding the hull might see.

The balloon will take weeks or perhaps months to get small enough to pull out of the ballast valve - the little hole to pop it will have no effect on strength or leakage and it gets the job done quickly.

As for the pounding, with my method you are actually making the panel stronger than new - remember, the inner panel extends beyond the limits of the existing panel, then when the new layers are added they effectively sandwich the original hull between the new panel and the new layers. This then creates a double-strength panel in the damaged area.

I would NOT cut any holes in the top of the tank... apart from creating a potential for structural failure or future leaks, it would be about twice as much work to repair.

[tangentair]

I would add that you should look at MAS epoxy's web site also, they have videos that might help and perhaps have a superior (and more expensive) product to the West system (which I have used a lot of so it is a good product also). Also MAS will help with technical questions if you e-mail or call them. I think the guys name to ask for is Paul but I am terrible with names so just ask for technical support help. They were very nice the time I called about building a new daggerboard.

[Divecoz]

I like most of Kevin's idea, though I would substitute the balloon for a single screw in eye bolt and a bridge to tighten the patch against the hull. I would question the balloons ability to exert sufficient pressure on the patch panel. I too as others have suggest might well, enlist a Professional ..........?
I would ask at this point ? Have you worked with Fiberglass repairs in the past? Have they been of a structural nature in the past?
IMHO and experience......just Slopping on glass and epoxy is much different than ending up with a quality structural repair that is as well unnoticable ....
again IMHO this may well be a project beyond your average novice's ability to perform on his own ........just IMHO...
this crack could well have a tendency to walk fore and aft...........

[kmclemore]

I agree that the eye-bolt is preferable, but that requires building a structure, and I've used the balloon trick in the past pretty successfully - it's cheap, easy and low-waste. As to the 'crack' spreading, yes, perhaps, but I had the impression that this was more of an impact hole, and as such if he does as I suggested - open the hole to the edges of the injury and radius all the curves, then it really should not spread.

As far as experience, yes, he should practice with the product prior to starting work, and do some reading if possible, too. However, I'm not particularly concerned, since if there should be a failure, it would not sink the boat - it would only flood the ballast chamber and that's not a huge problem. There is sufficient structure in the top of the ballast tank to keep the boat from breaking up, too.

[Divecoz]

3 - 1' pieces of 2x2 would suffice as a bridge ...... HOWEVER PLEASE!!!!! Follow Kevin's instructions to a T so as to end up with a good repair...cut grind bevel and as instructed!!!!
Kevin , if you have seen other examples of his work, is much like my brother's work. They both Measure everything with a micrometer and they mark with a diamond scribe they cut with an industrial laser they built one weekend for fun.... most the rest of us end up measuring with a old 30 ' tape measure marking with a crayon and cutting with a Saw-zall hahaaaa
Follow Kevin's instructions!!! It will work ,it will last, no one will ever know it was done....

[Night Sailor]

I"ve done this kind of thing before on structures and it's not difficult.
First look at many of the how to repair fiberglas videos on Google and youtube so you get an idea of the work flow. Make sure you have all the materials you need on hand before starting, including sovents and rags Breathing masks, old paint brushes, squeegees, etc..
Kevin's is correct, you must taper the edges of the rough hole so the outside dimension is quite a bit larger.
My method was to cut a piece of 1/8" or 1/4" wire woven screen or wire mesh (from most any hardware or farm store) two inches larger than the opening. (Doesn't have to be stainless or even galvanized. It's not going to bear the strength of the repair after it's all done so it can melt away over the years). Make a thick bead of epoxy filler compound around the edges of this screen about 2" wide. Fold the screen enough to insert it in the hole. Straighten out the screew and with a hook of wire or tool, pull the edges up on the back side all around the hole and wire in place around several dowel rods or similar moulding strips laid across the hole in parallel to each other. Be sure the wire mesh is drawn up as tight as possible to the backside of the hole all around. Let it cure. After curing remove the dowels and wire ties. Use your resin soaked cloth or mat to cover the bottom of the hole. Each succeeding layer should be larger than the last until you have a fine cloth, thoroughly expoxy soaked layer as the last one just below the gelcoat level. When is all is thoroughly cured, Trim any excess, then apply the gelcoat to thickness just a bit deeper the existing. When cured sand down to see if any edges or bubbles appear. Fill if necessary. Finish off the gelcoat by using compound and polish compound or a final sprayed coat if possible.
Hope this helps.

[kmclemore]

Divecoz, whatever would you do if they ever took away your exclamation point?


But then I suppose that would make it all pointless.

[Divecoz]

Divecoz, whatever would you do if they ever took away your exclamation point?


But then I suppose that would make it all pointless.

I guess I just wanted to be sure he knew.... the prep is really!!!! Important