Crack down the middle

RVC

New Member
I'm very glad I found this forum and hope to be an active part of it in time.

I was recently given an older Sunfish. I have never sailed a boat alone and hope to learn with this one.

One problem right off the bat is a crack down the middle of the keel (for lack of a better term). When the hull first arrived at my house it had a lot of water in it. So instead of trying to carry it up the driveway I rolled it up on several pieces of larger diameter PVC. It worked but created the crack. The crack goes all the way through as was evidenced by all the water that dumped out through it. I'll post a picture as soon as I can figure out how.

I intend to repair it by grinding the fiberglass down about 3/16" along most of the keel from the dagger board aft, filling it with several layers of graphite cloth and epoxy and then grinding it smooth. I have considered trying to separate the top of the boat from the bottom but figure this may be a bit extreme.

That's my intent at any rate, but I wanted to see if those on this forum more knowledgable than I might have a better approach.

Thanks for reading through this and for whatever help or comments may be forthcoming.

RVC
 
I'll post a picture as soon as I can figure out how.
Got a Flickr or PhotoBucket account? Just click the Insert Image icon
insertimage.gif
and paste in the path to a picture.



I intend to repair it by grinding the fiberglass down about 3/16" along most of the keel from the dagger board aft, filling it with several layers of graphite cloth and epoxy and then grinding it smooth.

I have considered trying to separate the top of the boat from the bottom but figure this may be a bit extreme.
Hull separation would be way extreme. Your first idea is more along the lines of what the fiberglass repair books walk you through.

Save the expense on graphite cloth too ... unless you've booked a spot for your boat on the space shuttle ... fiberglass cloth is what the boat is built with and it works fantastic for fixing it too. ;)

Grinders can often create more work than they save. 3/16" is just about all the hull thickness you've got to begin with. Rather, with this size boat, hand sanders, sanding blocks, and Dremel Tools tend to keep repairs from growing out of hand.



That's my intent at any rate, but I wanted to see if those on this forum more knowledgable than I might have a better approach.
Get some pictures posted and let's have a look at what you are dealing with.

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Hello Wayne. Thanks for your help, and I'm sorry to take so long to get back to you.

The only reason I mentioned graphite is I have a supply of it and don't have any fiberglass at present.

Hear are pictures of the affected areas.
Crack1.jpg


Crack2.jpg


Thanks again for your help.

RVC
 
The only reason I mentioned graphite is I have a supply of it and don't have any fiberglass at present.
A supply of expensive, high-tech fabric, lucky you. :cool:

I think I'd be inclined to get some reinforcement built up on the back side of the crack. This is a structural repair on a thin hull so IMHO needs a wider tie-in and beefier support than the typical cosmetic puncture wound might receive.

Remove the flotation foam if some exists.

Then, seeing how it's a sharp split rather than a wide ground down scuff type of damage, I'd "V" it out and flair the outer edges in typical fiberglass repair fashion, followed by layering in fabric to bridge the gap, filling out the "skeg" shape. Sand it back to accomodate a finish layer of gelcoat , then shape and compound into the surrounding surface.

BUT, first the insides need to be dried. Repairs won't take if the laminate has moisture in it.

4784840655_8abbc3bd08_b.jpg
 
Your grinding a "V" is pretty much what I was heading for and is the reason I mentioned using a grinder. Applying repairs to the inside would be ideal but problematic. I have considered this also which is why I mentioned separating the top from the bottom. Can this area be reached through the well - i.e. cut out part of the well, make the repairs to the hull and then repair the bottom of the well? How else would one proceed?

Thanks for the help.

RVC
 
Can this area be reached through the well - i.e. cut out part of the well, make the repairs to the hull and then repair the bottom of the well? How else would one proceed?
Does your model have the storage cubby?

sf7.jpg


The cubby has an inch or two where you can carefully chopstick resin soaked fabric underneath it.


The foot well itself is glassed right to the hull bottom with less than an inch cleareance down the middle so cutting through it presents new problems. Anyway, it appears only a small portion of that crack extends under the foot well. That bit could be left unbacked.

4634169404_55e18b4966.jpg



If your boat is pre-1971 you can put an access port in the back wall of the foot well. That would be the easiest access of all.

SunfishScud306.jpg


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My boat does not have the storage area. From what I have been able to learn from the KB, according to the serial number on the aluminum plate behind the coaming, it is a 1967.

As it turns out the main crack forward of the self-bailer lies completely under the foot well. If, as you say, I have an inch clearance at the middle of the boat I'm thinking of trying to cut maybe a 3 or 4" strip out of the bottom of the well with a straight bit in a router set just deep enough for the thickness of the well. Think that would work?

Thanks for the pictures and for sticking with me on this.

RVC
 
As it turns out the main crack forward of the self-bailer lies completely under the foot well. If, as you say, I have an inch clearance at the middle of the boat I'm thinking of trying to cut maybe a 3 or 4" strip out of the bottom of the well with a straight bit in a router set just deep enough for the thickness of the well. Think that would work?
First of all, Apologies !! :eek: I've been all discombobulated. Thanks for correcting me. I see now the crack is running forward not aft.

I follow what you are saying and there's good logic to it, given you have no fear of getting in where you need to. However...,

I hate to split the cockpit floor. It has no real support down the middle except its own tension across the pads it's cemented to a few inches further outward. Cutting into it will result in the center collapsing. Re-attaching the two halves with sufficient strength to be level and feel solid would get involved or creative or both.

My whole idea is to try and avoid large openings such as a typical blind patch from the outside would require. Opening the cockpit tub, though not nearly as integral to the boat's structure, is still something I would try to steer clear of.

I am trying to think how you could possibly pull wetted fabric through from one end to the other. Pulling it so it lays down the center of the hull isn't actually so complicated. A second access port in the tub's front wall will provide a way to thread a strip of fabric under the tub. The difficulty I see is, once the fabric is laid down, how to press it into the skeg and work it smooth for good contact. Not to mention how to get under there to sand the surface some.



Approximation of the resin cement points between tub and hull

4788682847_29900494e5.jpg

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Re: Crack down the middleps

What about filling the void between the cockpit floor and the base of the keel solid with either resin, resin with microspheres, or resin with chopped glass?

The first would be easiest but perhaps weak, although your talking about compressive loading, so you might be OK. The second option would be lighter. The third would be fairly strong, but probably hardest to install.

It obviously would not be as strong as a proper glass fabric repair. Instead, it would rely on the cockpit floor for structural support, by filling the void between the two.

Then you could repair the crack externally, and have reasonable assurance that it would hold.
 
I would grind and clean the crack with accitone and apply epoxyinside then on the outside put a couple of strips of fiberglass cloth or 6"tape over the crack and extend down along the keel sides coat good with resin and then bevel the inner edges then coat with goog paint. the hardest part is matching the paint up. remember you cannot fiberglass over epoxy with poly resin.
 
Thanks for your input there Chiefypoo - appreciated.

Thanks also to Ivy. Problem with that approach as I see it is that is a lot of resin and something would have to be done to allow the passage of water fore and aft under the cockpit. I assume that is necessary as the original design allows for it.

I think I'll try removing the strip, adding a couple layers of glass/epoxy on the inside of the crack then epoxying into place a piece of PVC sized to bridge the keel or skeg and be a point of bearing for the replaced strip of the cockpit bottom. Naturally the replaced piece of cockpit bottom would be glass/epoxied back into place. Sounds workable to me. What do you guys think?

The input and discussion are very much appreciated.

RVC
 
I think I'll try removing the strip, adding a couple layers of glass/epoxy on the inside of the crack then epoxying into place a piece of PVC sized to bridge the keel or skeg and be a point of bearing for the replaced strip of the cockpit bottom. Naturally the replaced piece of cockpit bottom would be glass/epoxied back into place. Sounds workable to me. What do you guys think?
The theory sounds workable. Major hull failure under the cockpit is about the most difficult to work on.

The only other option I have is to go back to square one. Work from the outside, removing a strip probably 6" wide and rebilding the skeg completely in that section. That would be a more traditional approach, now the question is what constitutes more work and better end results.


More views of where you are headed. . .

4790971374_7f08200124.jpg


4790973062_1aa7300dde.jpg


4790341799_42b39ae457.jpg


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I appreciate your input Wayne. It and the pictures have been very helpful. You obviously have a lot of Sunfish under your belt. I'll take pictures of my work and post them.

One last question if you don't mind. As you might have noticed in my pictures the self-bailer is the original aluminum one. I would like to replace it with a newer one and now seems as good a time as any to do this. How does one remove the old one? It appears the only way is to grind to old aluminum off on the inside. Is that the way, or is there a better one?

Thanks.

RVC
 
I appreciate your input Wayne. It and the pictures have been very helpful. You obviously have a lot of Sunfish under your belt.

I'll take pictures of my work and post them.

One last question if you don't mind. As you might have noticed in my pictures the self-bailer is the original aluminum one. I would like to replace it with a newer one and now seems as good a time as any to do this. How does one remove the old one? It appears the only way is to grind to old aluminum off on the inside. Is that the way, or is there a better one?

NP

Pictures would be very welcome. They help the next person facing similar repairs tremendously.

Use the search feature here to find a nice thread on cutting out a frozen bailer using a Dremel w/metal cutting disk.

Here's the bigger hammer approach ...


The plastic bailer is just a newer style of the metal one. Works pretty much exactly the same..., even leaks back a little like the old metal one did.

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replacing the metal bailer

I actually finally got around to doing this procedure this past weekend. Besides the above directions from Windline, one other bit of advice. After you are done cutting, if you can't budge the ring, try banging your hammer and screwdriver east to west, rather than north to south. In the Windline directions, he is shown hammering down (north to south) with his screwdriver. I tried this method, and the ring would not budge. I then started going east to west, and it finally started to move. Also, if you do go east to west, and the ring won't budge, it means you need to grind/cut a little more.

I actually used a jigsaw with a 3-4" inch, 1/4" wide little blade. I tilted it on an angle, and went slow. It worked fine.

The ring is brass, which means it is soft. So if you have got it cut enough, it will finally start to bend/budge.

Also, my bottom piece did not "plop" out as stated on the Windline directions. It was frozen shut with salt, so I had to tip the boat on its side, and then gently wack the hull piece back a forth with a hammer. It only took 3-4 hits to get it going.

Also, with the inside ring, once you have gotten one piece broken off, you can them just take the screwdriver and start to wack the remaining piece counter-clockwise, as if you are unscrewing it with you hand. Good luck.
 

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