Dave Lilley
Schertz, Texas
Boat Name:
Model/Year: 1977
Hull No. 7629
Hailing Port: |
 03/07/2006 12:35 PM Pacific Time
I recently purchased my boat (1977 - C22 #7629). One of the previous owners had put in a knotmeter sensor, about 5 feet back from the bow on the starboard side, in the compartment under the v-birth. The next owner removed this and used a 2” diameter thru-hull with an end-cap to seal the hole. I have only been out on the boat two times since buying it. There are no leaks at the thru-hull, and it looks solid. However, it does not have a plywood-backing block for reinforcement.
(I know that at some point, I probably should fiberglass over the hole in the hull and seal it permanently, but that this time I have other issues to tackle - assuming this setup will hold.)
Do I need to remove the thru hull, add a plywood backing, and then put the thru-hull back in?
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Al Gearing
Burleson, Texas
Boat Name: Torch of Freedom
Model/Year: C-22 '76
Hull No. 6448
Hailing Port: Arlington YC |
03/08/2006 5:34 AM Pacific Time
Not sure of your 2" with an end cap discription, but thru hull paddle wheel knot meters usually come with a plug that fill the 1" diameter hole and the paddle wheel is removed between uses so that it does not corrode, get sticky with what ever, and loose accuracy. If indeed that is what is in there I would just leave it. Some time when the boat is out of the water for a bottom job you might just fill the crack and sand over.
Al Ge |
Dave Lilley
Schertz, Texas
Boat Name:
Model/Year: 1977
Hull No. 7629
Hailing Port: |
03/08/2006 12:00 PM Pacific Time
The old knotmeter on this boat was larger - about 2" in diameter. I found it in a basket of old broken parts, along with the plug you describe. However, a previous owner removed it, and instead of glassing over the hole, he put in a 2" diameter through-hull. He then used an end-cap to seal the through-hull. (The end cap is a threaded plug made of the same material as the through-hull. An extension is screwed onto the through hull, and then the plug is screwed into the open end of the extension inside the boat. End caps are available most places that sell through-hulls.)
Anyway, after talking with tech support, I decided to remove the through hull and glass over the hole since I do not intend to use it. A local boat yard said they could glass over the hole, fair the hull repair, and re-gel coat the repair for $150. I have done a little fiberglass work before, but they will surely do it better and much faster than I could.
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Al Gearing
Burleson, Texas
Boat Name: Torch of Freedom
Model/Year: C-22 '76
Hull No. 6448
Hailing Port: Arlington YC |
03/09/2006 4:16 AM Pacific Time
Boy, that is different. But a small 2" hole should be easy to repair. As you thought maybe a piece of wood to re-inforce the area would be good. I would clean up the hole edges with a hole saw, (back it with a block of wood to drill it clean), then saw a piece of fiber glass near the same thickness as the hull with the same hole saw. This will give you an exact size plug with a hole kerf space around it that you can use filled epoxy to put in place. on the inside a bigger layup of epoxy soaked glass cloth will give more than adequate strength. Sand the outside smooth and your ready to do a bottom job.
For what it's worth,
Al Ge |
Steven Keplinger
Severna Park MD 21146
Boat Name: Nifty
Model/Year: 1978
Hull No. CTYH7999M78B
Hailing Port: Round Bay |
03/09/2006 7:26 AM Pacific Time
I'd do it about the same way as Al. The hole saw idea, and the plug made from existing glass of about the same thickness is excellent. But there's a rule in layup work: "matt then cloth". And it's a good one.
What it means, is you never put a piece of cloth on anything buy a recently laid up piece of matt. The matt, whether applied to chop, matt, woven-roving or cloth, holds more resin; and it has a way of noodling itself into every nick and cranny of the existing substrate. Fiberglass cloth will span small irregularities; consequently your bond may not be 100% with the substrate.
No biggie in most circumstances. But below the waterline is not most circumstances!
Anyhow, the $150 price is excellent. You'll spend the better part of fifty dollars getting all the stuff you need to make the repair yourself; assuming you have hole saws, scrap glass, protective gear, sanding and finishing equipment and all the minutia of misc. supplies and equipment that Al and I probably have stashed in three different locations [a guy can never have too much stuff...].
But it would be a great way to get into doing some of your own work. And, if you're like most of us, you'll soon want to add this or that to your boat. To paraphrase Ev Dirkson: " A hundred and fifty bucks here, and a hundred and fifty bucks there....pretty soon you're talking real money."
So do it yourself, or have it done; just make sure the layup is: matt then cloth. And always use epoxy for repairs. Polyester is good enough for most new work, but it frequently fails when used as a repair resin. Epoxy sticks better. |
Dave Lilley
Schertz, Texas
Boat Name:
Model/Year: 1977
Hull No. 7629
Hailing Port: |
03/09/2006 9:52 AM Pacific Time
Thanks for the tips guys. Those will come in very handy for future projects! I will be doing some fiberglass repairs to other areas, but I will leave this one to the pros. Frankly, I'm scared to tackle a hole like this below the waterline.
A previous owner of this boat (#7629) totally stripped and re gel-coated the bottom several years back. It is really smooth, and I dry sail my boat - so no bottom job. Since I don't have (or need) a bottom job at this time, the shop is going to also do the gel-coat work on the repair, so it needs to be a poly layup. I have done small (hidden) stuff with epoxy, but I have never worked with poly. Besides, the shop that is going to do the work specializes in fiberglass work, and they do nearly all of the repairs for the guys in the club, including the club boats. I know they will do it right.
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Dave Lilley
Schertz, Texas
Boat Name:
Model/Year: 1977
Hull No. 7629
Hailing Port: |
03/09/2006 10:00 AM Pacific Time
I forgot to ask one question. In a case like this, where the gelcoat is going to be repaired too, is it feasible to do the plug and outer layer from poly for the gel coat, but have the layup inside the boat using epoxy for additional strength? (...since the gelcoat cannot bond properly to epoxy, but epoxy can bond to the poly layer.)
I'm sure the shop knows what they are doing and will do it the best way possible, but I still plan to ask questions. I just don't want to sound like an idiot if I ask them this question.
Thanks,
Dave
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Steven Keplinger
Severna Park MD 21146
Boat Name: Nifty
Model/Year: 1978
Hull No. CTYH7999M78B
Hailing Port: Round Bay |
03/09/2006 10:35 AM Pacific Time
The epoxy should be used for the patch. The gel coat presents an interesting problem. I'd rather see it done without the gel; this presuming the hard patch (per Al's suggestion) is replete with its own gel coat. That way, the only exposed fix is the new epoxy resin; and it's just fine under a coat of bottom paint. And, even though you put-in-and-out, you probably should have bottom paint; if only to go faster!
If you do the gel, there's still no poly involved; except the gel itself. And it's tricky. Now the hole needs to be "let in" so the outside diameter is, say, 3/8" greater than the inside diameter. Ditto the patch. The patch itself must now be thinner than the hull, by the thickness of a layer of resin impregnated mat and cloth, applied as a wet sandwich; the matt being a tad less in diameter than the cloth, which comes within a nitch of the hulls surface. The void is filled in with fairing compound. I use (gasp!) fiber-reinfored Bondo. We're talking about a void here of maybe .OO1. Then the gel can overspray the Bondo-faired patch and the existing gel (which as been prepared for the new gel).
Below the waterline? Not me!
But if it's done right, it's invisible. Notice that the structural patch is all epoxy bound. The first poly is the Bondo, then comes the gel; pretty, but Oh so labor intensive. It can't be done for $150! Or, at least, I couldn't do it for that.
Just insist on an epoxy patch. But, unless you actually watch 'em do it, there's no way to know what resin/layup they use; 'til it fails. So get a warranty. |
Aaron M Benham
33a Loomis Hights
Boat Name: Tidely-Idley: The never ending project
Model/Year: 1978 C22
Hull No. 8070
Hailing Port: |
03/09/2006 12:20 PM Pacific Time
Might I suggest that you purchase a copy of "Hull And Deck Repair" by Don Casey before you decide what to do. $150.00 does seem kind of cheap and I would hate to see you get what you pay for. Fiberglass repair is really very very easy to do correctly and I'm often astonished to see how much money people pay to have someone else do it for them. The $15 that the book costs is money well spent even if you have someone else do the work. You will at least be able to see how they should be doing the job.
Remember, you can grind out almost any mistake you make and try again. |
Aaron M Benham
33a Loomis Hights
Boat Name: Tidely-Idley: The never ending project
Model/Year: 1978 C22
Hull No. 8070
Hailing Port: |
03/09/2006 12:21 PM Pacific Time
It's also kind of fun |
Steven Keplinger
Severna Park MD 21146
Boat Name: Nifty
Model/Year: 1978
Hull No. CTYH7999M78B
Hailing Port: Round Bay |
03/09/2006 12:51 PM Pacific Time
Casey's book is excellent. |
Aaron M Benham
33a Loomis Hights
Boat Name: Tidely-Idley: The never ending project
Model/Year: 1978 C22
Hull No. 8070
Hailing Port: |
03/09/2006 6:13 PM Pacific Time
If you have access to the inside with nothing to interfer with the repair (liner, bulkheads ect.) and you can make the repair from the inside then you can use gelcoat with the epoxy. The method the shop should be using is not the one described above. To make the strongest repair, the only kind you want below the waterline, you need to chamfer (bevel) the edge around the hole to a ratio of 12-15 times the thickness of the repair area. (if the hull is 1/2 inch thick then then total area of your repair would be about 14 inches or a 2" hole chamfered 6" all around) If the repair is being made from the inside (the easiest way from the standpoint of final finishing, the hardest from the standpoint of doing it while standing on your head), then you would back the outside of the hole with somthing that will allow you to match the contour of the hull as closely as possible. Your backing would then be covered with mold release wax and PVA to prevent the patch from sticking. The backing is then coated with the gelcoat which is allowed to gel. You then layup the glass cloth with each layer larger then the last. Your first layer would be slightly larger than 2 " the last 14".
Gelcoat won't adhere well to epoxy but epoxy will adhere to gelcoat. If the repair is done from the inside (you need at least 14" all around the hole to do it from the inside) then you would be applying the laminates to the partialy cured gelcoat so use of epoxy is possible thought not absolutly nesessary.You will also only have a 2" area outside of the hull that needs refinishing and most of the work is already done. If the repair was done from the outside, you would have a 14" area that needs to be compleatly refinished.
If you use epoxy though I have heard that it can react with the binder that is used to hold the strands together in chopped strand matt so it should be avoided. If you use poyester resin than you must alternate matt with cloth with the outside two layres being matt. I have not used epoxy for any of the repairs that I have attempted (all successful though not all on the first attempt) I left out several simple but essential steps above. Buy the book and give it a try. If you mess it up, grind it away and try it again. I have had to redo many of my repairs/restorations to get them right. Messy.
If you can, find a friend and help him or her fix their boat first. Don't be afraid of it, its not that hard. And it is fun. And you know the job will be done right, exactly what materials were used, the weather conditions the repair was done in, and how many layres of fiberglass were layed up at one time between curings. All important factors in a good strong under the H2O line repair. Remember, even if a shop warrenties their repairs, you are still going to have to get the boat off the bottom before they can fix their mistake |
Al Gearing
Burleson, Texas
Boat Name: Torch of Freedom
Model/Year: C-22 '76
Hull No. 6448
Hailing Port: Arlington YC |
03/10/2006 3:20 AM Pacific Time
Gosh fellas, that book may say you need a 12:1 scraf joint and for some large area patches I would agree. But this is a small 2" hole. If it was a knotmeter, there has to be access from the inside. Sanding the inside of the hull a few inches around the hole with a block sander to assure a clean area of glass to put a 4"-6" backing should be easy, and IMHO more than adequate.
Al Ge |
Steven Keplinger
Severna Park MD 21146
Boat Name: Nifty
Model/Year: 1978
Hull No. CTYH7999M78B
Hailing Port: Round Bay |
03/10/2006 3:35 AM Pacific Time
Ya' gotta love this list. Who knew this would be such a hot topic!
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Bob Vick
Caldwell, TX
Boat Name: Over Keel
Model/Year: <1985
Hull No. 13059
Hailing Port: Lake Somerville |
03/10/2006 5:44 AM Pacific Time
Simplified:
Bevel Sand around the 2 inch hole about +6 inches inside & outside.
Cut out circles of glass cloth to match your hole & depth of hole.
(To match inside & outside sanding areas) (Clean with acetone)
Lay the layers out upside down
Get some wax paper & a small rolling pin from the kitchen
(Don't let the wife see you)
Mix up enough epoxy to do the job & soak everything
Pancake stack everything with the epoxy syrup on the wax paper
Slap on the outside patch & roll on with the roller to match the hull
Go inside & slap on those pancakes & roll of sponge into place
(I left a zip lock bag with water in it to contour the shape)
Go back outside & roll the bubbles out, if it is sagging use a soft sponge to hold the sag out, it should not sag. After the epoxy cures, but before it sets remove the wax paper.
Sanding should be minimal; it will look so smooth you will be tempted not to sand it.
You can add a white pigment to the epoxy top coat, gel coat should not be used, it is weaker & if the previous bottom job was done with Epoxy you will have a bonding problem. Remember epoxy can go over anything & is stronger; gel coat can only go on gel coat. Only manufactures use gel coat, Google epoxy & gel coat, you will have a hard time finding gel coat, for good reason. I use West System, it is available locally, and other brands will work.
Hell it is simple but so much for a simplified version...
Boatless Bob
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Aaron M Benham
33a Loomis Hights
Boat Name: Tidely-Idley: The never ending project
Model/Year: 1978 C22
Hull No. 8070
Hailing Port: |
03/10/2006 12:02 PM Pacific Time
Consider how many gallons of seawater per miniute will come through a 2" hole and how big a pump you would need just to keep up with it. I bet nobody here has a pump that size on board. I've learned the hard way that its is the about the same amount of work and sometimes less to do it the right way as it is to do it the wrong way, especially if you add in the loss of sleep and worry of having your family aboard a questionable boat. The method Bob describes above is not difficult and if epoxy is used will result in a repaired area that is stronger then the original hull. Even if done with polyester resin it would be just about as strong as it was originally. Something to consider when the boat is heeled over the repair and out of sight of land. A plug type repair on any size hole is prone to sudden failure as a minor failure could push the whole plug out as the water started coming in. Also, I don't see how that type of repair is easier than the correct method, especially when your trying to match the curve of the hull. |
Dave Lilley
Schertz, Texas
Boat Name:
Model/Year: 1977
Hull No. 7629
Hailing Port: |
03/10/2006 1:03 PM Pacific Time
Good suggestions all. I have the complete Casey repair manual, so I will review it and help / watch while the repair is made. There is good access inside and outside, so there shouldn't be any problems. All of the guys I know trust and use this shop for all of their repairs because of their excellent work and low prices. I know the gelcoat thing complicates matters a little, but I trust the shop knows what they are doing.
If they get in there and say they can't do it for some reason, I guess the worst that happens is that I have them reinforce the through-hull and leave it in. |
Fred Apstein
Gabriola Is BC
Boat Name: Scruples
Model/Year: 1976
Hull No. 95
Hailing Port: Gabriola Is BC |
03/11/2006 2:00 AM Pacific Time
Polyester resin is not as good as epoxy, but it's as good as the rest of the hull. The pros at the repair shop will probably use polyester because it simplifies the job, costs less, and it's easy to sand and Gel coat the outside when they're done.
I have bought, repaired and sold several damaged boats over the years and done the repairs under the supervision of well qulafied marine surveyors in order to be able to show the buyer's insurance company and buyer's surveyor that the job was done right.
It is critical to grind the glass well so it's beveled inside and out and clean and free of old paint and gel coat. Gel coat often has wax in or on it, so it's not safe to leave it under a hull patch that will be under water. You can't be sure the patch will stick to it.
No surveyor ever questioned the strength or adhesive properties of polyester resin.
The standard for hull repairs is to bevel the edges, grind out any jagged edges or cracks or tears in the hull, then overlap the complete repair patch at least four inches over the cut out area inside the hull.
Four inches of overlap is misleading, because the layers of the patch must each be two inches larger than the one underneath.
Otherwise the patch will make a "hard spot" in the hull which could flex the glass of the hull and crack. The two inch overlap makes the patch thinner at the outside edges to avoid a hard spot.
First layer is four inch overlap, second layer is six inch overlap, third layer is eight inch overlap. Three layers of one mat and one roving is probably as thick as the hull.
I would use maybe three layers of a thin mat and cloth on the outside patch. Cloth is a bit stronger than roving. The finer weave makes more glass to resin. Glass is strong. Resin, especially polyester, is weak.
I use a lot of epoxy when I do small repairs. It really sticks better, and with the right fillers it's very versatile. I think in this case a professional would choose polyester resin. |
Fred Apstein
Gabriola Is BC
Boat Name: Scruples
Model/Year: 1976
Hull No. 95
Hailing Port: Gabriola Is BC |
03/11/2006 2:13 AM Pacific Time
Another perhaps easier approach is to intstall the through hull properly and leave it capped. No gel coat repair.
Remove the thorugh hull. Mask the outside of the hull so it doesn't get resin on the gel coat.
Grind inside the hull and reinforce around the hole with two layers of one mat, one roving. one six inch square (or round if you like) and one eight inch, to avoid a hard spot. If you want more layers, it's easy at this point. Just don't make a hard edge.
Cut out the glass, reinstall the through hull with good bedding compound inside and out, and youre done.
I would not use plywood for a through hull backing on a glass boat. It will rot sooner or later. I know lots of builders do use plywood, and I've repaired the results more than once.
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Dave Lilley
Schertz, Texas
Boat Name:
Model/Year: 1977
Hull No. 7629
Hailing Port: |
03/11/2006 6:07 PM Pacific Time
Hey Fred, It is funny that you mention just rebedding the through-hull properly, because that is exactly what I may have to do. I took the boat to the shop today, and after they looked at it, they said there was not enough space inside to make a proper patch. The alternative is to patch from the outside with epoxy and then paint. However, given that I think that patch would probably be very noticeable, I think the best choice is to properly install a flush, capped through-hull.
Dave |
Fred Apstein
Gabriola Is BC
Boat Name: Scruples
Model/Year: 1976
Hull No. 95
Hailing Port: Gabriola Is BC |
03/12/2006 3:50 PM Pacific Time
Dave,
A good job on the through hull is a lot easier than your other options. If you want to be double safe, it would be really easy to fill the through hull spigot (The threaded part inside the hull) with some silicone sealer, then screw on the cap.
It's probably fine without extra backing under the inside ring, but it's easy to put some extra strength in there if you want to.
Good Luck! |
