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Sunfish Hull Repair

Gunksman

New Member
All, I have a 1978 Super Sunfish that needs some hull repair. It has two or three pencil eraser sized holes a few mm deep along the keel and some minor abraded spots along the chine on both sides where the FG mat is exposed. I bought Marine-Tex to do the repairs and plan to do it all in one sitting with maybe a second coat if needed.
It's warm enough now so I plan to do it this weekend. Any recommendations, warnings, tips?IMG_7432.JPGIMG_7433.JPGIMG_7434.JPG
 

Alan S. Glos

Well-Known Member
White MarineTex is definitely the goop of choice for these repairs. A hint. Put in just enough MarineTex to fill the dings and then cover with heavy duty smooth plastic wrap. Smooth it out with your finger and then tape it tightly with Gorilla Tape. When the MarineTex cures, the plastic wrap will peel off and you will have a mostly finished repair or just need a little wet sanding. MarineTex is great stuff but hard as rock when cured and hard to sand.

Alan Glos
Cazenovia, NY
 

L&VW

Well-Known Member
It's not "Great Stuff". ;)

All, I have a 1978 Super Sunfish that
It's warm enough now so I plan to do it this weekend. Any recommendations, warnings, tips?
Judging by appearances, probably not going to be your problem, but MarineTex will "yellow" if one's Sunfish is stored deck-down and exposed even to "northern" sun.

I've forgotten the remedy :rolleyes: but a little wet sanding may restore the finish. (I think I spray-painted over my repair--a postcard-sized area).
 

shorefun

Active Member
It is hard to tell from the picture, but the damage on the chine looks like the glass is broken. If that is the case I would not use marine tex. It really should be glassed for strength.

Keep in mind even marine tex need some properly sanded area for a good bond. That means you need to sand out the hole some and put in the marine tex. The taper on into the hold increases the hold on good material and creates a stronger repair.
 

Gunksman

New Member
It's not "Great Stuff". ;)

Judging by appearances, probably not going to be your problem, but MarineTex will "yellow" if one's Sunfish is stored deck-down and exposed even to "northern" sun.

I've forgotten the remedy :rolleyes: but a little wet sanding may restore the finish. (I think I spray-painted over my repair--a postcard-sized area).
Thanks, though I keep it in the garage on a trailer, deck-up so having the Marine-tex yellow isn't an issue.
 

Gunksman

New Member
It is hard to tell from the picture, but the damage on the chine looks like the glass is broken. If that is the case I would not use marine tex. It really should be glassed for strength.

Keep in mind even marine tex need some properly sanded area for a good bond. That means you need to sand out the hole some and put in the marine tex. The taper on into the hold increases the hold on good material and creates a stronger repair.
Thanks, the damaged area is about an inch by a half inch. Yes, the glass is broken, but given the size and that my current trailer won't stress that area, do you think marine-tex will or will not work?
 

Gunksman

New Member
It is hard to tell from the picture, but the damage on the chine looks like the glass is broken. If that is the case I would not use marine tex. It really should be glassed for strength.

Keep in mind even marine tex need some properly sanded area for a good bond. That means you need to sand out the hole some and put in the marine tex. The taper on into the hold increases the hold on good material and creates a stronger repair.
Thanks for the info. That's helpful.
 

shorefun

Active Member
So here is my take on repairs.

I have worked with many different materials doing repairs. I play with restoring antique cars and I fix whatever comes along if I can.

After having repaired holes in 4 different sunfish and recently seen a few marine tex repairs in a 420 I have an opinion.

I think for larger holes like yours you are much better off structurally with doing glass. The marine tex is hard as a rock, the glass has give. I can see it being more likely to crack or damage at the edges because they are dissimilar in hardness. I would also think if few hits on the chine, which happens a lot based on all the Sunfish I have seen, it might be more likely to have an issue down the road.

If you put a backer in of mat glass and layer up the outside and gel coat it then it will likely never have a problem.

I posted back in the fall how I did a chine repair with a blind backer you can look up.

In either case, the strength is from having a nice taper around the hole to give a lot of area for the new material to bond to the old. If you are doing a thick marine tex then you will want to make sure it is worked into the edges. The bonding is by getting the epoxy to go into all the scratch from the 80 grit (or what is recommended by marine tex).

The rest of the spots are fine with either material.

If you get gel coat get a tint kit for $9 and watch boatworks today for his gel coat color matching. You need to knock the white down a bit with some black, a very very small amount of black, and a bit of yellow. If you are better at color matching you might figure it out better then me, I am real bad at it.
 

Gunksman

New Member
It is hard to tell from the picture, but the damage on the chine looks like the glass is broken. If that is the case I would not use marine tex. It really should be glassed for strength.

Keep in mind even marine tex need some properly sanded area for a good bond. That means you need to sand out the hole some and put in the marine tex. The taper on into the hold increases the hold on good material and creates a stronger repair.
Thanks for the info. That's helpful.
So here is my take on repairs.

I have worked with many different materials doing repairs. I play with restoring antique cars and I fix whatever comes along if I can.

After having repaired holes in 4 different sunfish and recently seen a few marine tex repairs in a 420 I have an opinion.

I think for larger holes like yours you are much better off structurally with doing glass. The marine tex is hard as a rock, the glass has give. I can see it being more likely to crack or damage at the edges because they are dissimilar in hardness. I would also think if few hits on the chine, which happens a lot based on all the Sunfish I have seen, it might be more likely to have an issue down the road.

If you put a backer in of mat glass and layer up the outside and gel coat it then it will likely never have a problem.

I posted back in the fall how I did a chine repair with a blind backer you can look up.

In either case, the strength is from having a nice taper around the hole to give a lot of area for the new material to bond to the old. If you are doing a thick marine tex then you will want to make sure it is worked into the edges. The bonding is by getting the epoxy to go into all the scratch from the 80 grit (or what is recommended by marine tex).

The rest of the spots are fine with either material.

If you get gel coat get a tint kit for $9 and watch boatworks today for his gel coat color matching. You need to knock the white down a bit with some black, a very very small amount of black, and a bit of yellow. If you are better at color matching you might figure it out better then me, I am real bad at it.
thanks very much for the thoughtful response. I was hoping to get the boat in the water quickly and that Marine Tex would help me do that. I don't have glassing skills. Maybe use the Marine Tex on the holes and a very light coat on the glass abrasions so I can sail it. Then work on the glass work?
 

Gunksman

New Member
Thanks for the info. That's helpful.

thanks very much for the thoughtful response. I was hoping to get the boat in the water quickly and that Marine Tex would help me do that. I don't have glassing skills. Maybe use the Marine Tex on the holes and a very light coat on the glass abrasions so I can sail it. Then work on the glass work?
So I followed the instructions for cleaning, sanding, cleaning and applying the Marine-tex. Worked great! I think I need to apply a second layer in a couple of places but it's just fine to get the boat in the water right away.
Thanks everyone for all of your comments!
 
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wjejr

Active Member
I just got a 1980 Sunfish and the bow handle came off. Can I put an inspection port behind her and then bolt it down?
Hi Frank, The short answer is, “Yes,” but I would try desperately to avoid it. The simple reason is that an inspection port on the bow IMHO is not, how shall we say, aesthetically pleasing. I have one on the stern of my boat, and every time I look at it I regret putting it in, even though it was necessary, or at least I thought so at the time. Others will disagree, but the only place where I think an inspection port makes sense in a Sunfish is behind the splash guard/rail in front of the daggerboard.

Instead, I would insert a bent coat hanger into one of the holes and see if the backing block is still there. If it is, I would put the boat upside down on saw horses and squirt some thickened epoxy into each hole with an irrigation syringe. You can then quickly put some masking tape over the hole so the epoxy doesn’t run out. Once the epoxy cures, you can drill it and insert new screws.

If the block isn’t there, then you have bigger problems. If you have an inspection port behind the splash rail, I might try inserting two strings in the bow cleat holes, one front,one back and see if you can fish the strings from the inspection port, you will need to lift the bow so that the strings fall down to the splash guard. To make that easier, I would tape a nail to each string, so that gravity will pull the strings down. If you can grab the strings, then you can drag a new backing block up to the bow by drilling holes in the block using the new cleat as a pattern. Once the new block is in place, you can epoxy it. Looking at where the foam blocks are supposed to be this should all be possible, but you never know for sure until you try. If you don’t have an inspection port behind the coating, you should still be able to see if it works by inserting a string with a weight, or maybe even a fishing line that electricians use if the hole is big enough. You should be able to hear where the end is, and if you get it back near the coating, I would put the port there. After the repair you can buy a “cat bag” for the port and keep your phone, key, suntan goop, etc. in it.

Or you can just go the simple way, and cut a hole in the bow.

All of the above is my opinion of course, but I hope you find it helpful.

Good luck!
 

L&VW

Well-Known Member
Or you can just go the simple way, and cut a hole in the bow.
All of the above is my opinion of course, but I hope you find it helpful.
Good luck!
That's what I did. The handle had disintegrated upon my purchase, and I wanted to bolt the new handle on. I didn't want to spend actual money on an inspection port to compromise the smooth lines at the bow. :oops:

The hull of my tired ex-racer had already been painted blue—then I painted it white. (So retaining the hull's gelcoat wasn't a consideration).

I used a metal-cutting blade in my saber saw to make as narrow a cut as possible. The space in there is very tight, but I managed to epoxy the Nylocks in, and secure the bow handle with machine screws. (All stainless hardware). A replacement bow handle is a long way off, but the four machine screws should be operable indefinitely.

I bonded some short lengths of fiberglass sail battens to the backside of the cutout section, and when that had cured, bonded the edges thoroughly to the hull. What imperfections there were, were filled with Marine-Tex.

Here it is, with a bungee cord being prepared to provide the necessary outwards tension :

P8020008.JPG
 
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