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Suggestions for what appears to be a cosmetic hull crack

po-man sailor

Active Member
I have a couple good cracks in the hull bottom gel coat on the keel line. Have no idea how some idiot did these two crunches but it doesn't appear to be leaking or soft. I want to seal it up and smooth it without leaving a big ole obvious fiberglass patch. Can I just push in some marine tex and smooth it out to a dressed finish. Or is there a simple product or gell coat that will hold up?
Thoughts from you experienced guys...I like simple permanent and clean. Ill attempt to post pics.. Thanks
 

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L&VW

Well-Known Member
Two on the keel are structural. Whatever cosmetic fix you use will eventually leak.

One I fixed was due to strong storm wind, which flipped my Sunfish up to hit a fixed dock post. The damage looked just like yours. :(
 

Woodwind

Active Member
....and try the trick that Alan Glos posted a while back. Get a piece of plastic that’s heavier than Saran Wrap, maybe a Ziploc bag or even a piece of visqueen...but if you don’t have any other plastic around you can use saran wrap for this, but it just works better with a little bit heavier plastic.
After you apply the Marine Tex smooth the plastic over it and rub it down with your fingers gently to the contour that you’re patching, don’t worry it will not stick stick to the Marine Tex. After the marine tax hardens then pull the plastic up.

When you pull up you’ll have a shiny nice gelcoat like finish, it won’t required sanding if you do this carefully.
It is amazing how well it works.
I used it to patch a few spots in my newly acquired Sunfish and it worked beautifully.

Cheers!
 

Cactus Cowboy

Well-Known Member
I'm with L&VW on this one... do it right, fair out the surrounding areas, and re-glass the damage properly. Might even rough up the existing cracks and use some cloth fibers inside 'em as filler, prior to laying cloth down on the keel and hull. Otherwise, filler like Marine Tex will simply crack again as the hull flexes longitudinally, or fore & aft. Best spend the time and effort to keep the hull watertight. Just my $.02... as for the damage, I'd say the boat was dropped on a curb or something, or struck with another heavy object. :confused:
 

signal charlie

Well-Known Member
Staff member
Comments above are educational, yes, you should probe and prod the area and visually inspect to make sure there is not crushed (cloudy) or soft fiberglass underneath. By cleaning out flaky bits I mean clean out the material until you get to good, solid fiberglass. Repair if needed. And Marine Tex epoxy putty is indeed structural.

I'd say the boat was dropped at one point, or it could be trailer roller rash.
 

shorefun

Active Member
Everyone is talking without enough information. Those cracks took some force to make, you must look at what is below it. Without grinding away the gel coat no one can tell you what will actually work.

Its the keel an it is the structure of the bottom so it has to be right. I have a hull that has a cracks like you see. The worst looking area is just the surface. The not so bad one is all the way through. In fact, this hull must have had water getting in all the time. They put silicon around everything. I was doing a basic probe of the cracks and found a minor crack with a bit of gel coat covering it was likely their water leak. There is a 1/4" hole.

With the 4 hulls I have plus an opti I have learned you can not diagnose a problem without grinding it back. You really have to grind back the area to see what you have. Even if you only marinetex the hole you have have to grind it back to give the epoxy something to stick to or it is a useless repair.

Quite frankly I would not do anything less then a grind back, glass a few layers and gel coat. That will fix the structure and you will be assured they will hold. It is not hard to do as I have learned and it is are really solid repair.

Just slopping Marine Tex in will be hit or miss if the area is not prepped properly.
 

L&VW

Well-Known Member
Quite frankly I would not do anything less then a grind back, glass a few layers and gel coat. That will fix the structure and you will be assured they will hold. It is not hard to do as I have learned and it is are really solid repair.

Just slopping MarineTex in will be hit or miss if the area is not prepped properly.
Yup.

I attempted a Marine-Tex "repair" years ago, after my keel got a good whack.

It didn't take long for water to find its way inside. Perhaps it was pulling the Sunfish up on the dock after a sail, but I ended-up doing a "grind and fill" operation with epoxy.

This early in po-man's Florida sailing season, I'd be tempted to simply tape over the damaged areas. The rest of the hull is strong enough to resist "creeping" damage. (Anxious to go sailing, I've done it a couple of years in a row). :oops:

Remnants of the white Marine-Tex material can be seen covering (and to the right of) the keel damage.
 

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po-man sailor

Active Member
Ok....I'm paranoid enough now that I'm going to grind back and down a tad and do a fiberglass patch job. This is a very dry boat and I don't want to take even the slightest chance of getting water in the hull I don't need. Then take all sumer to dry it out and put ports in.
I usually just use fiberglass resin and harder on other transom jobs and repairs. Is that what I should use on this or are there better products out there I'm unaware of? I'm pretty old school fiberglass but no objection to tech improvements.
 

shorefun

Active Member
Ok....I'm paranoid enough now that I'm going to grind back and down a tad and do a fiberglass patch job. This is a very dry boat and I don't want to take even the slightest chance of getting water in the hull I don't need. Then take all sumer to dry it out and put ports in.
I usually just use fiberglass resin and harder on other transom jobs and repairs. Is that what I should use on this or are there better products out there I'm unaware of? I'm pretty old school fiberglass but no objection to tech improvements.
Glass will do the job. I would just be a bit generous on feathering further back some. More area for adhesion the stronger the repair or so I believe.
 

L&VW

Well-Known Member
You've probably already finished with the repair, but here's more keel repair information provided by members Whitecap , webfoot1 and me...:


Although next time, I'm gonna remove a much bigger section of keel, use battens for support, stuff glass into the cut, and extend resin and glass further to all sides inside. (The factory roving is relatively unfinished on the back side).
 

Webfoot1

Active Member
If you mess around with used Sunfish Sunfish the damage shown is very common. Get
familiar with the Shoreline method of repair because you'll be doing it many times. The
good part is you can add extra layers to the back of the damaged section you removed
so that it's pretty much unbreakable when replaced. If you want to try something quicker
put in the typical inspection plate behind the splash guard and apply fiberglass through
the inspection hole. Not quite the correct method because the crack will still be present
on the outside but better than a band-aid repair. Sunfish don't just teach you to sail,
they also teach you fiberglass repair. Maybe you'll find out which one is more relaxing.
 

L&VW

Well-Known Member
If you want to try something quicker
put in the typical inspection plate behind the splash guard and apply fiberglass through the inspection hole. Not quite the correct method because the crack will still be present
on the outside but better than a band-aid repair. Sunfish don't just teach you to sail,
they also teach you fiberglass repair. Maybe you'll find out which one is more relaxing.
That'll work if the keel repair is forward of the daggerboard trunk.

My repair was under the cockpit, so there was very limited access. (Although I have several spare inspection ports, and could install one in the cockpit floor!) :p
 

po-man sailor

Active Member
Yep unfortunately my damage is under the cockpit Right next to the drain plug and under the compartment behind the cockpit. Soooo. I put it off and went to other items that need doing that are less labor intensive till I get a whole day in the sun. Thanks as usual for all the input both the ones I'm not using as we as what I am. Its all educational.
Po-Man OUT!
 

Cactus Cowboy

Well-Known Member
That's what I like about ya, Po-Man!!! You're appreciative of other site members, lol... :eek:

And YES, all posts here at this "world-class nautical website" are edumacational, in one sense or another... ;)

Even if they teach ya what NOT to do, BWAHAHAHAHAHAHA!!! Ain't my first day out, BTW, I just like extreme small craft sailing... :rolleyes:

Well, I'm about done with the realtor gal for the day, I'm working on a beer buzz now and thinking about making that heller batch o' burrito mix, WOOHOO!!! :)

If you were here on my property, I'd offer you a cold beer and an eventual place at the dining room table, because that's the sort hospitable man that I am... :confused:

Back in Coronado, over the decades, I must have had 1000 guests par-tay, mack good BBQ or other grinds, and crash at the ol' hacienda... :D

To me, that's the TRUE meaning of hospitality, making sure NOBODY goes away hungry, and offering a place to crash if needed... DAMN RIGHT, LOL. :cool:
 

po-man sailor

Active Member
Ok guys, I went out today and sanded back the gel coat on the 3 damage points and actually found another one closer to the starboard rear. Like a jab of something pointy or a small rock.
Anyway here are some pics. I notice there are some voids around the small cracks so I sanded gel coat back beyond them but did not go deep or in the light colored what appears to be voids. All holes in the glass were small but I fear they could have let water in my dry hull. I think the moron that took this boat in for carpentry payment and knew nothing about boats did all this damage while hauling it home. It wasn't put back in the water and thats why she's still dry after the damage. Sad...and lucky but she's mine now and I need to deal with it.
Ok guys cut loose with your opinion now that you have a visual of what I'm dealing with. Do I need to completely grind out all the voids. Even if they don't have holes to the outside? What then?...put chop and polyester resin back in? Or whats the deal with thickend epoxy or polyester resin?Structure doesn't seem to be hurt. It just looks like potential leaks.
Thanks
 

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Cactus Cowboy

Well-Known Member
Well, that Shoreline Method sure seems complicated, I'm gonna offer a "Po-Man's Suggestion" which might be as effective. Those white areas where you see exposed or dried cloth, those all have to go, that cloth is nothing but trash now, you understand. It looks as if some of these damaged areas could be accessed through the hull void by installing inspection ports in the deck or cockpit... this would make life easier for you, as you could then put some backing in place in each damaged area and just rebuild atop that backing, the hole faired out in every direction on the outside, AYE? You may be able to access several damaged areas through one port, so think before cutting. Backing "plates" of cardboard securely fitted (taped, pinned, whatever) to each location will allow you to simply rebuild the hull area that is MIA... the key here to a strong bond is fairing out the hole and exposing solid glass upon which to build. Even if you grind clear through the hull, you can rebuild each area, just don't grind any more than you absolutely must, 10-4? :confused:

That would be my first suggestion, as inspection ports aren't that expensive and they're easy to install. However, there's another way to do this, utilizing 'West African Engineering' methods & techniques, lol. Say you grind that trash away and you're left with holes clear through the hull or keel. And furthermore, let's say that this is an area where inspection ports won't be of any use... no worries, ol' Cactus has you covered, lol. You're STILL gonna need some backing for each area, that much is certain. So you cut a thin cardboard backing piece just larger than each hole, use an awl to punch a hole in the center, thread some fishing line or other thin but strong line through the backing piece, roll or fold or manipulate the backing whichever way you must to get it through the hole, use a screwdriver or popsicle stick to flatten it out as best you can while gently pulling upward on the line, and "seat" the backing piece into place in the hull void, tying off the line to some overhead object. That object can be near or far, doesn't matter as long as it holds the backing in place. :rolleyes:

The important thing to remember here: you want each backing piece snug enough so that your expensive catalyzed resin doesn't simply drain into the hull void as you attempt the repair. That is KEY, the sooner you can get one good solid layer of cured glass in place over that hole, the sooner you can build the area up without worrying about any backing. The whole idea is to have a surface upon which to place that initial layer of cloth or matt. No surface, no dice... provide a surface upon which to build, and the rest is easy, you'll just put multiple layers over that initial layer. Be patient and let that first layer atop the backing cure all the way, right? Once you have that first cured layer in place, just build up the area with pre-cut patches cut to size as needed. Again, fairing out the area surrounding the damage or hole is very important, you want a good bond to form between existing glass and the layers you rebuild. Some may disagree, but I've used this method before and it has worked perfectly... no need to rough up the glass in the hull void, focus upon fairing out the glass facing you. ;)

Once you've rebuilt those damaged areas, you will have to sand 'em smooth so they look like they originally did. No big deal, seems like you can handle the job. it ain't rocket science, but remember: only fair out the glass around each hole or damaged area as much as necessary, don't grind clear through if you don't need to do so. Get enough solid glass exposed as you fair out each area, that will ensure a solid bond as you rebuild layers of glass. Some of those pics show damage where you might not have to grind clear through, though you want to get rid of all that worthless trash if you can. You already know what the repaired areas are gonna look like, compared to the surrounding gelcoat, so I would recommend priming & painting the hull with 2-part LP afterward, that'll hide all the ugliness and make your boat look like a million bucks. Right, that's all then, time for this kid to grab another cod beer, I've been playing "phone tag" (or "text tag") with this realtor gal all day. Wish I could go back to the good ol' days, when smoke signals were used for communication, lol. :D

P.S. That cardboard backing can be thin, like the covers of those notebooks used by students in school. Any stout paper or other flexible but resin-proof material can be used as backing, you can always line it with plastic if necessary. It just has to be flexible enough for you to get it through each hole, and you have to be able to work it into place as backing, AYE? My first recommendation is for you to install inspection ports where needed, that way you can fix the backing in place more securely, and also remove it once you're done with the glasswork. Meh, you'll figure it out, I have faith in ya... and I'm known for creative solutions to problems like this, where things can get expensive if you let' em, lol. When I pulled this sort of repair in the past, the rebuilt areas were just as strong as the original hull, the key to strength and a good bond lies in fairing out the damaged areas. Enough said, don't hesitate to ask further questions, I like this project and I intend to follow the thread until you are done, the boat fully functional again and looking like a million bucks, lol. CHEERS!!! :cool:

Edit: Forgot to mention that you'll have to make one radial cut in that first patch or layer of cloth you lay down, just to let the fishing line remain undisturbed while it holds the backing in place. As soon as that first patch or layer is cured, cut the line with a razor knife to get rid of it, but be sure the first layer is strong enough before you cut the line... might have to put another layer down, using another radial cut, just don't let those cuts lie one atop the other, yeah? The backing is only temporary, needed long enough to get that first layer or two into place, after that you're home free and can simply rebuild the area. :)
 
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po-man sailor

Active Member
Thanks cactus! I agree.. The shoreline method looks good and strong but a bit over the top for me. I can't convince myself to cut that kind of hole in this hull. LOL
I was wondering if I would need to grind out all those places where there never was a hole but were lighter in color as if they were a pre-existing voids below the surface from the manufacture or caused new from the impactin combination with a less than perfect dry bond originally. It sounds like it needs to all be removed and built back up. I can do that but my try concern is getting a finished look after patch is done.
 
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L&VW

Well-Known Member
Answer is still the Shoreline method.
Nice photographs--thanks. (And good restraint on sanding--the keel is surprisingly thin). The light areas are weakened and need attention.

What appear to be tiny holes through the keel are tiny holes in the keel. Sand some more, and they'll be quarter-inch squares. Why, you ask?

That's the end of the coarsely-woven fiberglass roving material with which the factory thought to lay down the keel (and the rest of the hull).

With only one exception, any other repair than the Shoreline Method can be counted-on to fail again. Why, you ask?

Because the keel takes a beating whether dragged up wood docks or over rubber rollers. :( The wetter the boat's interior foam, the worse it gets. Pull the boat up, and listen to the crunching sound! :eek:

The exception is the inspection port, where an ugly, but firm, "mat" patch can be placed inside and then the outside can be faired smoothly to finish the job. In this case, 'not such an easy installation--given the cockpit location(s) of the damage.

Four-inch fiberglass tape covered with six-inch tape is an expensive alternative, as you'll need about six feet of each to make a smooth repair from daggerboard to transom. :confused:

Briefly, I agree with Webfoot1.
;)
 
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Cactus Cowboy

Well-Known Member
Meh, I disagree, I've done keel repairs on various small craft and they NEVER failed, in fact they were STRONGER than the original material. Of course, some of my repairs were a bit thicker (in the hull void where it made no difference), but I've been known for overkill. :rolleyes:

"WHAT?!? CACTUS?!? OVERKILL?!? GTFO!!!" ;)

Again, I think the key to a solid repair is in the prep work, in choosing the right time & weather conditions to effect the repair, carefully laying glass matt or cloth layers on a thoroughly-wetted surface, wetting layers further as ya go & eliminating air bubbles, and fully rebuilding the damaged area so it's bulletproof... :confused:

But no worries, it's good to see all these different opinions... and some of my repair methods have been ordered by economy rather than convention, lol. Sure, if ya got the dough, use a Husqvarna chainsaw to cut through the hull in the Shoreline Method... :(

I can see it now in big marquee letters, and on the Silver Screen: 'THE TEXAS SHORELINE CHAINSAW MASSACRE!' :eek:
 

Webfoot1

Active Member
Why the Shoreline method works for me is often the tub has a crack down the middle. I
can fiberglass the bottom of the tub before moving on. The whole idea was to reuse the
broken piece by encapsulating it in fiberglass top and bottom. Normally you would never
reuse the broken part but this is so you have a easy way to retain the keel shape. There are
other valid ways to make the repair, it's just what you feel comfortable with. You can sort
of look at the Sunfish as a mostly non-mission critical boat. Other boats that can't overcome
their ballast weight when compromised, not so much.
 

L&VW

Well-Known Member
After you apply the Marine Tex smooth the plastic over it and rub it down with your fingers gently to the contour that you’re patching, don’t worry it will not stick stick to the Marine Tex. After the marine tax hardens then pull the plastic up.

When you pull up you’ll have a shiny nice gelcoat like finish, it won’t required sanding if you do this carefully.
It is amazing how well it works.
I used it to patch a few spots in my newly acquired Sunfish and it worked beautifully.

Cheers!
Keep in mind that any printing on the plastic material will transfer to the repair medium. For a time, you may have to live with repairs advertising Frederick's of Hollywood or Victoria's Secret...! :p
 

Cactus Cowboy

Well-Known Member
Hey, L&VW, is that a new racing technique? Distracting the competition with soft porn as ya round marks or sail in close proximity? Damn... :eek:

I haven't heard the name 'Frederick's of Hollywood' in decades, that outfit is still around? Jeez, you'd think they would've retired by now... or died. :rolleyes:
 

shorefun

Active Member
First off I am just a beginner with limit glass experience. That being said I have an intuition on structures.

The glass repair counts on properly roughed up surfaces for bonding. So a long properly roughed up surface in a structure area will be very strong.

When looking at the type of damage you consider what the full damage of the surrounding glass. In your case it is not very far. You go at it with a sander and some 80 grit and you will quickly be able to find the bad areas and figure out a repair. You problems seem very localized and I believe a well ground out and layered repair will do just fine. If the hole is larger as you sand it out you might have to make a decision to make a backing patch you put through the hull or cut the inspection port.

I did some repairs on a hull and one area had a couple inch hole on the keel. I did a backer patch with cardboard and laid up a bunch of layers of glass. I am sure that fix will last a long time.

If it fails then you can do a shoreline repair.

Personally I have a problem with the Shoreline repair because I do not think their doublers go out far enough to make sense. That is they do not have enough attachment to be structural. All the structure is the glass laid up on top the seam. Which then brings me back to there are many ways to do glass work and they are all correct.

I would love to talk to someone who knows the science and math behind fiberglass bonding in repairs to gain a better understanding. So far all I can go on is seeing like 15 different experienced glass guys each with a different structural method of repair and all saying this is good. I go back to basics of what I know about getting things to adhere. There are 2 issues with glass. A good bond to the previous layer and a large enough surface area to be bonded to on the part you are fixing. I think if you follow those two rules just about anything works for Sunfish work.

So my thinking on keel repairs is you need to have longer repair area so the bonding area is spread out to handle the flexing you might see.

In the end, if it breaks again then you can always do a larger repair like the Shoreline method.
 

Webfoot1

Active Member
I make my own fiberglass battens for the underside. I differ from what they show by grinding off
all the gelcoat on the removable part. After the part is glued in the entire part and it's attachemnt
area is covered in one piece of fiberglass. You could grind to the surrounding area to the 12%
of damage point but it's not needed here. Going out to about where Shoreline shows the repair
is rock strong being bonded top and bottom. I've also got about three layers under the damage
for max overkill. If somethings going to break again it will be in another area. Sunfish are Flexable
Flyers and the splash rail is the only thing trying to work against flexing, often failing with pulled
screws. If you pull off the trim opposite the splash rails there is 50% chance the hull seam has
split in that area. That's why Sunfish type boats with a splash rail molded into the deck are often
considered better than the Sunfish. Too bad the Scorpion seemed to have problems with the
gel coat after aging. Seemed to totally detach itself from the fiberglass and break up into little
chunks.
 
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