I just purchased my first catamaran, a Nacra 5.2, and took it out for the first time last weekend. Unfortunately I found out that the hulls leak a lot more than what the seller indicated. I thought he was a decent guy, and told me they leaked only "a few cups." Unfortunately its really more like gallons. When I put the boat on the trailer and cinched down the ratcheting straps, I could see that this caused water to leak out the bottom of the hulls right by the front crossbar. It seems that its coming from the seam where the two fiberglass pieces are molded together.
Today I took the hull off, turned it over, and sanded off the gelcoat on the bottom where the seam is. I filled a bit of water in the hulls and found a fine crack where water seems to seep out of. Its just right near the seam. I took several pictures of this, but it is difficult to see the water coming out. I can see on the inside of the hull that one of the previous owners has laid down some fiberglass on the inside of the hull where this crack is in order to fix it. Clearly that didn't do it.
I want to fix this, but I am not sure of what the right technique should be. Should I just try to fill in the crack with epoxy? Should I sand it down to be thinner and lay down some strips of glass on top and fair it with epoxy? Or should I completely cut this section out of the hull and try to lay down glass from the inside? The last option would be most difficult, as while there was an access port added where the damage is, there is also some extra glass and epoxy down there that makes a rough surface.
I've got some epoxy and microspheres on the way from uscomposites.
Here is a link to the pictures of what's going on:
http://www.flickr.com/pho…76489390@N06/7011488017/
I wish this forum gave us the ability to upload pictures.
I appreciate any advice.
Nacra 5.2 bottom repair
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Posted: Mar 24, 2012 - 11:58 AM
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Posted: Mar 24, 2012 - 01:57 PM
I hope the only problems I have with my hulls will be the upper decks. I am going to add some gel coat to the bottom edges because it shows the clear resin from being loaded and unloaded on a trailer (just an assumption as to the cause of the missing gel coat) I did fix a small fiberglass boat once by grinding out the cracked area to be able to get some epoxy with glass fibers into the place where the crack was. It held up for years but wasn't put to a lot of stress like the hulls on a catamaran might get. -
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Posted: Mar 24, 2012 - 02:09 PM
Be careful with ratcheting straps, you can easily make a bad problem worse, or just create a new problem from the force of the straps.
IMO to do it somewhat right, you should pop that front deck off, and lay a pretty thick layer of epoxy/glass on the inside of your cleaned crack ^^. Then once it cures, flip the hull over and sand through the damaged area until you reach the patch, then rebuild w/ a little glass. Finally fair w/ the microballoon fairing compound.
Then find a new deck and put it back on w/ cabosil thickened epoxy. Your current deck's inspection port weakens the whole hull in a bad spot.
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Rob
OKC
Pile of Nacra parts..
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Posted: Mar 24, 2012 - 07:20 PM
Hi yurdle, thanks for the reply.
Yeah, I'm a little mad about this purchase, I think the guy kinda screwed me. The boat looked good at first, but there are several things that were wrong with it now that I've got it. I see why its a good idea to have someone who knows that model boat when buying it.
I probably will never find replacement decking for the boat, so I'm really hesitant to mess around with it. There's another 5.2 on sale for $750 near me, and I was thinking about buying it and taking the good parts off of it, and selling the rest from both boats. That is nearly half the price I payed for mine.
I think someone already tried to lay down a thick layer of glass in there, unfortunately whatever they did is not water tight. I think my best shot will be to sand through from the outside until I reach their repair job and lay down new glass and epoxy from the outside. Hopefully that will bond and make a strong repair. -
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Posted: Mar 24, 2012 - 07:37 PM
I'm almost positive I have an extra front deck. Where are you?
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Rob
OKC
Pile of Nacra parts..
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Posted: Mar 24, 2012 - 08:18 PM
you can you just need the [im g] code
Edited by optikid on Mar 24, 2012 - 08:23 PM.
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Angelo
1983 Hobie 16 Cat fever #55697
2008 laser 4.7/radial #190471
SARASOTA, FLORIDA
S.S.S
S.Y.S.P
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Posted: Mar 25, 2012 - 12:56 AM
Hey. If strength and hull integrety is the issue you have one probem. If leaking is the the issue you have a differnet problem. To me the bottom looks like many years of dragging on the beach has caused leakage.. ALSO>> Perhaps too much pressure on the tie downs on rollers in transport may have stressed the seam at the keel.. The fix for me for a olde boat that still rocks (and the 5.2 does) is to seal the H2O leak from the inside ,, do a fix-it leak patch inside the hull( Add a bit more glass than necessary to that area .. fore and width) since you have access to the keel and after sealing the leak and add... some glass to the outside (if necceary) to prevent further damage if necessary.!! (Be carefull not to plug the drain holes from the front sections of the hull( see Chris177 here on the photos on the inter hull photos ( Chriss U rock??))) .. AND sail the Pis* out of her .. And Get or Make ( I will have a photo log of this on B Cats soon) on makin trailer guides/cradles so the hull are not on just rollers on the trailer but more surface area to ease the pressure on the keel on the trailer.. Don't get P**ed off, even to the guy U got it from. U will never regret it! U have a 5.2.. Enjoy the balance and the spirit and the "coolness" of a 20+ year olde boat that was WAY AHEAD OF IT"s TIME and still rocks.. Like living with the a lady love you never had.. she rocks!! Say By By to H 16s and 18s.. Horizon Time !! Cheers H
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Hal Liske
Livermore CA
H 16 (6+ 1.. Friends) H 3.2 N 5.2 (2) H 17 (2) H-18
Nacra 5.8 (son's) H 20 (Friends)
It's a Sickness
I Need a A Cat Please
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Posted: Mar 27, 2012 - 01:49 PM
Halliske, you sure got the spirit! Amen hallelujah!
Looks like minor trailer damage and wear 'n tear to me.
I popped the lids off my bows last year using a small chisel, working round a bit at a time. The cracking sounds may freak you out but don't worry, a liitle epoxy goes a long way! Just open 'm up so you can get at the rough repair, grind her down quickly with one of those flapped sanding disks and wet out with the epoxy, add one layer of heavy glass, ( 4" Biaxial tape is truly excellent for this!) wet some more and wait. Mean time check for delam on the internal strengtheners and repair where neccessary, If there are any kinks in the stringers, fix and add a reinforcing tube there from side to side. Just wrap a cardboard roll in glass and epoxy it in place.
When it comes time to put the decks back on, clean em up and coat the edges in unthickened epoxy, which should soak into the cracks made with the chisel. Then glue in place while still runny with a moderately thickened batch. Heaven help the poor bugger who ever has to go in there again, but it'll be plenty strong for another couple of decades.
Some health tips: Clean up epoxy with vinegar, better for your health than most chemicals and actually works well. Don't sand green epoxy, let it cure. Then let it cure some more. Oh yes, using a highly efficient sanding disk on a grinder *may* p1ss off your neigbors, so watch out if the wind is blowing in the general direction of their new car. (Don't ask me how I know this) -
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Posted: Mar 28, 2012 - 09:53 PM
Thanks for the advice halliske and dennis. Actually most of what you see was caused by me using my disc sander with an aggressive grade disc. I wanted to see what was actually going on with the fiberglass below.
Dennis, what I found actually was that someone had already done just what you suggested, which is why I found my boat has extra ports on the fore decks. And I'm the poor bugger that has to go in and fix it... what happened was that the glass they laid down did not bond to the hull completely on one side of the boat, leaving a less than watertight seal.
I just tried to break that glass away as best as I could, and I sawed a decent sized hole in the bottom. I'm laying down one layer of glass from the inside, but I'm then going to lay up another two sheets from the outside to bond to it. I tried to clean it up on the inside, but its tough to prepare a surface that has 30 years of crud on it, even after sanding and acetone. Hopefully that will give a better seal. I'll fair any rough edges with epoxy mixed with microballoons.
Its tough that the repair has to be right on the bottom edge though. I'll have to remove a fair amount of gelcoat to get my outisde glass to bond to the hull. -
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Posted: Mar 29, 2012 - 01:21 PM
Remember that the hull has drain holes. Perhaps a pressure washer would help get the crud out. Especially if there is a bit of flow out the cracked seam... It might identify where the glass did not bond. Can you get a small hand held grinder in there?? Perhaps a Dremmell even.. For me, I would rather do more layers inside and have less to fair on the outside. Again, remember not to plug the drain holes near that keel.. Though not as serious, I am down to the glass on a small section of one hull on my 5.2. Might be easier and look cool to do a new layer of gelcote (colored??) like that cat that is forsail in the classifided.. Looks COOL Cheers H
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Hal Liske
Livermore CA
H 16 (6+ 1.. Friends) H 3.2 N 5.2 (2) H 17 (2) H-18
Nacra 5.8 (son's) H 20 (Friends)
It's a Sickness
I Need a A Cat Please
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Posted: Mar 29, 2012 - 01:26 PM
http://www.thebeachcats.com/classifieds/catamarans/p11859-nacra-6-0-1994.html
I would have done it in RED and less of the keel .. No acounting for taste but red is Nacras color.. Hal
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Hal Liske
Livermore CA
H 16 (6+ 1.. Friends) H 3.2 N 5.2 (2) H 17 (2) H-18
Nacra 5.8 (son's) H 20 (Friends)
It's a Sickness
I Need a A Cat Please
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Posted: Mar 30, 2012 - 03:30 PM
Yeah, that color setup is really nice. I think all red would look really sweet though. At least until the gelcote got scratched enough that it there were many white scratches.
I already found out right where the boat leaked from, it was at the seam right near where the hull sits on the front trailer roller. Probably due to both wear and hull flex from too tight tiedown straps. Its in the same spot where a previous owner laid down some glass, but his repair didn't seal the hull 'cause it didn't bond the inside.
Well, I ended up laying down a single thin glass "wear strip" about 2 in wide right down the seam. Then I added epoxy with microspheres on top. It worked well on one hull, but the other one I let cure outside overnight and the dew totally screwed up the epoxy cure. It came out looking like orange rust dripping down the side of the boat. Time to get out the disc sander again.
For future reference, I think it would have worked equally well to try to seal the cracks with thin epoxy, and then later apply a thickened epoxy layer right down the midline of the boat as a wear strip. What I've got seems watertight now, but we'll see how well it holds up to mechanical flexing and such. -
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Posted: Mar 30, 2012 - 05:03 PM
With your wear strip, you're leaving uncoated epoxy and microspheres on the bottom? Or did you apply a layer of gel coat over it as well? I'm planning out a bottom job on my boat, too, so I'm fishing for ideas.
Tom
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Tom Benedict
Island of Hawaii
P-Cat 18 / Sail# 361 / HA 7633 H / "Smilodon"
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Posted: Mar 30, 2012 - 07:30 PM
First, thanks for the thread, I was about to convince myself to blow off flipping my P-16 over to put a wear strip on the keels. I can feel glass mat on the bottom center of my keels and you can see light through them. I plan to put Marine Tex on the keels in the center area to about 1/8" and sanding that smooth. I have white hulls so it should be a reasonable solution both from a cosmetic and functional basis.
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Mike Brady
Sugar Land, TX
Sailing off Magnolia Beach in Lavaca Bay TX
http://358degrees.blogspot.com/
P16 "Pooh Cat"
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Posted: Mar 30, 2012 - 08:23 PM
3...2...1...GO!
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bill harris
hattiesburg, mississippi
prindle 16- "BLUE RIBBON"
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Posted: Mar 31, 2012 - 09:49 AM
Well, first off I'm not anything near an expert on this. I haven't tried it out yet.
But I think that the microsphere epoxy mixture will likely wear down pretty quickly. After all, that's what its really designed to do-- to be easy to sand. So its probably bettter if it gets a layer of gelcoat or marine paint over it.
I heard Marine Tex wears well, but I already had epoxy and wanted to avoid buying another product. The microsphere mixture is really easy to apply. Its just like spreading icing on a cake.
I got the epoxy from www.uscomposites.com. It was $35 for a system with a quart of epoxy and its hardener. Way cheaper than the $60 for the equivalent West System from my local West Marine.
Also, I laid down a glass "wear strip" which serves the dual function of keeping the two molded halves of the nacra hull bonded together. I think other models of cats may be made differently and don't have the seam on the bottom. For better wear resistance I could have chosen kevlar, but I've heard that the epoxy doesn't sit as well in it. Also, I wanted to get the job done now and I didn't have time to wait for it.
I can say thought that this operation was much easier than I thought it would be. I tested the hulls by putting water in them and they seem to be watertight.
I haven't decided, but I think I'll coat the hulls either with Interlux brightsides or with gelcoat. I think I've got to redo the whole hulls. I'll have to brush either on as I don't have spray equipment. It seems like gelcoat would be the "right" way to do it, but brightsides would produce a nicer finish for less effort.
I'll post some pics of the work in progress soon. -
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Posted: Mar 31, 2012 - 10:41 AM
Ok, that makes good sense. So if I do go this route, having a final coat of something hard (epoxy, gel coat, paint, etc.) is a good idea.
On the kevlar thing, a guy I used to know did a lot of layup work with everything from fiberglass to carbon fiber to kevlar. He said the big thing with kevlar is you can't sand it. It'll fuzz every time. Just the nature of the beast. So if you need the mechanical properties of kevlar, by all means use it. Then cover it with a thin layer of something else so you can sand it fair. His application was making pressure vessels, so the higher tensile strength of the kevlar was a huge plus. But these were used exposed in an airstream, so they had to have a really clean profile and surface. Hence the sandable outer layer.
Looking forward to seeing the photos of your work.
Tom
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Tom Benedict
Island of Hawaii
P-Cat 18 / Sail# 361 / HA 7633 H / "Smilodon"
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Posted: Apr 01, 2012 - 12:20 PM
For the final coat, I'd go with gel coat if it were my boat, paint if I were selling Gel is way easier on maintenance, on the bank account, can be quite easily color matched and has second to none wear resistance. You can just buff it up if it gets dull or dirty. The orange peel effect you get with a roller is only visible from really close and will only cost you a place in racing if your ego is sensitive to the type of comments you may expect within two to three boat lengths of the mark. If you can spray paint, then I wouldn't worry about it at all, unless you are really vain and need to check up on your tan while at the beach.
If you apply gel over the epoxy, let that cure very well first and sand it at around 220 grit to give the gel enough grip. -
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Posted: Apr 01, 2012 - 12:57 PM
Hope I'm not hijacking this thread, but after what dennisMe said I figured this was the perfect place to ask:
I've heard gel coat doesn't like to stick to epoxy. Why is that, exactly? Is it mechanical? Or is it chemical?
I've got a ton of holes in my boat (drilled out rivets, moved screws, all kinds of stuff the previous owner(s) hadn't finished working on). I've got at least a full day of drilling out and filling holes before I take this out on the water. I was planning to use West Systems epoxy and filler for this.
I saw a video on Youtube where a guy was patching a hole on a boat. He did the glass work with epoxy, cured it, sanded it, and then put a layer of polyester resin over that to give the gel coat something to bond to. Then he did the gel coat work, sanded smooth, and compounded.
I figured he did that polyester resin step because of the whole gel coat not sticking to epoxy thing. But I thought gel coat was a tinted polyester resin! So do they have the same problems with adhesion to epoxy?
Heck, if I can just sand it 220 to give the gel coat a good mechanical bond, that's straightforward enough. But I'm willing to go that extra step if that's what's called for.
Tom
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Tom Benedict
Island of Hawaii
P-Cat 18 / Sail# 361 / HA 7633 H / "Smilodon"
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Posted: Apr 02, 2012 - 05:22 AM
I can only answer from personal experience. I read so many conflicting opinions on the matter that I decided to just give it a try. I have an older boat and basically nothing to lose, so I figured, what the heck!
I have been using epoxy for repairs all over my boat since I bought it, about five years ago. I went with epoxy because I had the stuff lying around and it is an actual glue, unlike polyester which is not much of a glue at all.
Anyway, here's what I did, as accurately as I can remember:
When it came time to remove the decks on my Nacra 5.2 early last spring I did everything with epoxy because I didn't want the deck seams failing under load. I also encountered some spots which required grinding/sanding out all the glass and re-laminating the structural laminate from scratch.
I let the (correctly measured and mixed!) epoxy cure for two full days at around 20 degrees celcius. I wiped the epoxy down with household vinegar and after that, with acetone to remove any possible amine blush. Then I sanded using 220 grit (At the time I was afraid this may be too coarse, but it was perfect in practice) and applied two coats of pre-thinned gel coat with a roller.
Because the boat required new anti-slip tape I later (a couple of weeks later) applied IKEA anti-slip tape. A month or two after application, I removed a lot of that because it was eating through my harness and a guest cut his shins on the stuff climbing aboard. Although the tape was firmly stuck on by now, none of the gel coat came off with it, which surprised me as I was really expecting the worst. To be fair, not all the tape was over epoxied areas, but there were definitely some under there.
Last month I removed the rest of it to replace it with decent anti-slip tape. I had one littl espot where some gel coat let go, but only a tiny fragment actually broke free (approx. 1cm x 1mm), which was excellent considering I had to use a knife to get the tape off and pulled as hard as the tape would let me without it breaking.
The above experiences lead me to believe the issues that gel coat may have when applied over epoxy are probably due to incomplete cure or differences in prep work. OTOH, there is a lot of variation from one brand of epoxy, or even gel coat to another and even more variation in circumstances (temperature, humidity etc).
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