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While Commander 105 was pulled , Robert and I pulled the leaking speedo transducer and head thru hull fittings. I n case someone didn't know how thick these hulls were , have a look;
Speedo at the turn of the bilge it is actually thicker than it looks as we have beveled it for the repair.
One of the head thru hulls;
And the repairs
Mike
I wonder how many of us have done that yet? It's on the books for 113. It looks like you just tapered the edges back and put a little flubber on:p Depending on who's book you read, I thought you HAD to grind a 1:12 (or something close) and refill with layers of glass and epoxy/resin. Then, do you grind on the inside or outside of the hull? The inside would probably be prettier on the outside, if you know what I mean. Or- throw some epoxy in the hole and toss a couple of layers of glass on the inside? I was planning on grinding the head through hulls on the outside because it doesn't have to be pretty looking below the water line and I could use them as practice runs. Then I thought I'd grind the side deck scupper through hulls( remember the ugly ones) frome the inside so there isn't a 12" circle on the outside. So...to make a long story short, what'd you do there?
Those are about 8" diameter circles , dished slightly with a 36 grit grinder , the holes were then beveled from the outside to half way in at 45 degrees . Clean up the holes and area real good , then put a temp backing from the inside .
Now apply 3-M premium underwater vinlyester blister repair compound , it has a short strand filler . I apply in 3 to 5 layers about 10 minutes apart .
The shape of the repair in cross-section is like a rivit head or tapered plug.
You can cut a 1/2" backing block and apply to the inside with 5200 , but it is not necessary .All the force is from the outside .
You can also do the repair with multiple cut disks of fiberglass and the resin of your choice but that is much messier and time consuming and not any significantly stronger .
The whole job was done in 2 1/2 hours sanded ready to paint.
Materials were about $25 and we only needed 1/2 of what we purchased.
You can't find where the old fittings were on #45, it is easy to fill and sand and make smooth again with 80 grit on a DA sander .
Have done destructive testing and found the material to be as strong as the hull .( I did a repair on an abandoned boat then hit the repair with a ballpean hammer , 20 hard blows and the repair was still holding but the original glass was starting to go.
Vinyester bonds well to old glass, is more waterproof than epoxy and can be sanded about 30 minutes after applying. If it were a wooden hull I would use epoxy .
Mike
Being a blister repair compound, can it be used above the waterline?
Above , below or on the waterline, it's all good!