Plastic Hunter Crack Repair

[Rictifyit]

You Guys were right, and I was wrong!
I put on the bow hardware today, and found that one of the screws spins, and the other 3 don't give me much confidence. They feel like a screw does when it's just about to let go, and start spinning.
I did not test them well enough when I took off the hardware, and now, I'm afraid to sail it. My plan was to sail it tomorrow, but the image of the mast, boom, sails, and a bunch of cables falling on me is giving me pause.
If I take a big screw driver, put it through the hole in the hardware, and lift up, the thing feels solid as can be. But I've been deceived before by my exuberance.
Does anyone know what is under that hardware? If you laughed, and said, "Yea, rotten wood", you'd probably be right.
My first idea is to take the hardware back off, and then cut the Luran so I can peel off a big piece of it to see what's what.
I need to sleep on this first. I'm not giving up, but I am feeling pretty stupid about now, so if anyone has an idea, let me know. I bet you thought you were done with me.

 

[BobbyFunn]

You have some pretty decent finishing skills. Smooth.

You know what has to be done.

Remove hardware. Remove the least amount of luran and see whats under there. Maybe cut an access port in the cuddy cabin to get a backer plate there. If you make an acces port get lots of pictures of the inside.

Sailing tomorrow? Have you rigged this up in the driveway yet? Go sailing. Whats the wind forecast?

 

[Rictifyit]

@BobbyFunn Ok, Good! I thought about cutting a hole in the cuddy to gain access. Good idea, and thanks for your comment about finishing.
I was going to rig it in the driveway today, but gave up on it. Will definitely do that first!
One thing I didn't mention earlier is that I am almost certain that there is nothing but air about an inch and a half under the hardware. I took a coat hanger and stuck it down the screw holes to see if they had a bottom. Nothing.
Like you say, a backer plate would be the best, but first I need to get the rot out. I'm thinking it will be like what was under the mast step hardware, but who knows really. There, it was 5/8" plywood.
I will proceed with caution. Thanks for the encouragement.

 

[Rictifyit]

@BobbyFunn What's below is what I expected. Nothing, except a piece of half inch plywood nestled in the foam sandwich.
I tested all the screws more, and they all spun, so I drilled a half inch hole to see what was there. I did a lot of head scratching, and decided not to use a backer plate because I don't want to cut a hole in the cuddy, and I think that when I screw it down against the fiberglass and foam it will compress. Not expecially a bad thing I guess. You're welcome to try and convince me.
Simply, I plan to drill all the holes out to either 3/4'" or 5/8" and fill the void with a hardwood dowel, or epoxy. Probably West system 105, or something like that. It depends on what epoxy is the best for screwing into. I might add silica to give it strength.
I've got a week to figure it out because tomorrow morning I'm going to drill out the plywood to 1/2", and add a Rot Terminator epoxy to stiffen up the plywood. I used it on the mast step wood replacement.
Anyway , I attached my notes about my plan. Thanks again for your constant help with this stuff.
5-27-20 Edit: The only thing that I did from any of the above post was to use Rot Terminator. It seems to cure up nicely, but takes a week because it is a slow cure, and has a low viscosity. I am using a backer plate, contrary to what I wrote earlier. And, my Great Stuff expanding foam idea ( in my notes ) does not work.

 

[BobbyFunn]

Hope you get some good responses. If you like the quality of the wood can you move the hardware 1/2 inch after filling the holes?

You cant use the luran as a medium for holding the screws. Pretend the luran shell doesnt exist.

Get yourself a 4" hole saw a 15 dollar access panel, some G10 backer plate, some stainless bolts and be done. No paint, no finishing, 100% job well done. Id still seal the core with epoxy and drill a clean hole.

 

[Rictifyit]

I have 6 days before the Rot Terminator ( not just for rotted wood, but compromised) cures completely, so I have time to decide what to do.
You @BobbyFunn have me convinced that a backer plate is best. I found out what G10 is, and read a thread on this forum about G10 Vs SSteel, so now I have an idea about what it is. The smallest piece from Jamestown Distributors is 1/4" x 2"x3", and the Stemhead ( another new word to me) is 2"x3 1/8", so that's convenient. I'm assuming I don't need a larger plate?? From reading the thread G10 Vs SS for Backing plate, I learned that it should lie flat. I imagine that the underside of the fiberglass/foam/luran sandwich is not exactly flat. So do I slather 5200 on it first, and figure that will take up any gap? Will the plate bend to the shape of the fiberglass underside? I'm not concerned now about smooshing the foam sandwich because I am going to fill each of the 4 5/8" holes with West Six10 Thickened Epoxy adhesive first. That will prevent any crushing of the foam. This would be after I drill out the Rot terminator.
I already own a 6" access panel. I got it for free when I purchased another sailboat with holes in it. Lol,, next year's project. So I would use that instead of a 4" Any reason not to? The only problem I have is that it doesn't sit flat against the bulkhead. Again, fill it with 5200? I don't really care if it looks cockeyed.
I have time before the epoxy arrives, and I have to order the plate too, so I will have all week to ruminate about this new uncharted territory.
I was pretty set on using the old screws with new epoxy cores to screw to, but it's just not as slick as using the backer plate. Thanks for pushing it. I listened this time.
Any other thoughts/replies are invited.

 

[BobbyFunn]

You wont be disappointed. I'd like to get your camera in that 6" hole and see whats in there under that stay hardware. Look for the bow eye, and if possible get the picture of under the cuddy looking aft. There may be more wood in the hull. Get rid of it. Did you cut the access hole already?

The foam hull has a single layer of biaxial cloth opposite the luran it should be flat but never know close to the edge like that. A small plate will work fine. You may need to cut a triangle to get it to fit. A dremel will work.

It would be cool to just plug those holes, but then they might pop like corks someday.

G10 is alien technology. It bends, but dont plan on it. Imagine a glass dinner table that you can drill holes in. It feels like glass in your hands, but is plastic. Its hard to cut, but sands easily.

Some epoxy with high density filler will give you a flat base, between the inner hull against the biaxial. You used to just have wood so no need to over engineer this. You could probably use oak board and get good results for another 10 years. If you have to cut the biaxial to get a flat spot, lay down some cloth over the foam so there is a hard surface area for the plate. The foam is highdensity, but it needs support.

I bet you just made all the regulars nervous that there is no backer plate there, just the same paradim used for rudders and motor mounts and masts, now we all need to take 15 year boats and redi the stay hardware too. Im nervous now.

 

[Rictifyit]

You wont be disappointed. I'd like to get your camera in that 6" hole and see whats in there under that stay hardware. Look for the bow eye, and if possible get the picture of under the cuddy looking aft. There may be more wood in the hull. Get rid of it. Did you cut the access hole already?

The foam hull has a single layer of biaxial cloth opposite the luran it should be flat but never know close to the edge like that. A small plate will work fine. You may need to cut a triangle to get it to fit. A dremel will work.

It would be cool to just plug those holes, but then they might pop like corks someday.

G10 is alien technology. It bends, but dont plan on it. Imagine a glass dinner table that you can drill holes in. It feels like glass in your hands, but is plastic. Its hard to cut, but sands easily.

Some epoxy with high density filler will give you a flat base, between the inner hull against the biaxial. You used to just have wood so no need to over engineer this. You could probably use oak board and get good results for another 10 years. If you have to cut the biaxial to get a flat spot, lay down some cloth over the foam so there is a hard surface area for the plate. The foam is highdensity, but it needs support.

I bet you just made all the regulars nervous that there is no backer plate there, just the same paradim used for rudders and motor mounts and masts, now we all need to take 15 year boats and redi the stay hardware too. Im nervous now.

I think I'll cut the access hole today. I hate jig saws! I'll duct tape my phone to my wrist, and get some pics. Lol.. ring ring....
I too am curious about what's up with the bow eye.

Once I drill holes in the new epoxy screw hole cores, I'll make a template from the inside by using a piece of paper to superimpose the screw holes onto. I can't just drill into the plate using the hardware as a guide because I don't know how straight I can drill through the hull. I may make a wooden copy of the plate to see how it fits against the biaxial. There won't be any room, or light for me to cut the biaxial cloth, so the plate will need to fit well to the inner hull within reason. I can modify the plate to get it close, easier than modifying the inside of the hull. I'll dry fit it all, and then use the Six10 thickened epoxy adhesive between it all ( like you suggested ) to take up any gaps when I bolt the whole mess together. Hopefully, the West Six10 is nice and thick, and won't ooze out of any small gaps.

Haha, Nice image of the hole plugs popping like corks! Frankenboat is supposedly a Birthday gift to my Woman on June 5th. The idea of using the G10 backer plate makes me more confident this birthday won't become infamous.

I'm not sure many "regulars" are reading this novel. But someday, someone else will have the same bow cracks and rot. Hopefully this "fix" will be helpful.
I don't think the PO really knew just how weak the hole thing was. The cracks were covered up with fiberglass and paint, but the screws were not biting into much.

Oddly, not testing the screws well enough initially was a good thing. This fix will be better. The ply wood is really just suspended inside the "sandwich". Had I taken the whole bow apart to replace it, it would have been quite a mess to put it all together again with any sort of structural integrity. Better off just working around it!

 

[Rictifyit]

@BobbyFunn I couldn't sleep, so I got started. Starting off with a laugh at all the expanding foam that didn't do anything that I told it to. So it was a good idea to open this up. Pulling out all that naughty foam was not fun. I lost a big peace as it rolled down into the boat, but I was able to retrieve it by sucking it back with a vacuum.

As you can see the bow cleat screws are screwed to nothing but the sandwich. At least there's no wood to rot. AND, I found a metal backing plate on the bow eye! So glad it wasn't wood!

The fourth pic is heading back toward the centerboard trunk. You can't see it, but the first section of it houses the vertical PVC support below the mast step assembly, and then in back of that is the centerboard trunk. Nothing really remarkable, but good to know what's under there.
Now for some sleep.

 

[BobbyFunn]

Nice pictures. Thank you for posting those. That pretty much completes the entire collection of the internal hull. Bonus points for the hull deck seam.

Couple items to note:
There is sealant on the screws for the cleat. There is proably wood in the core.

The deck floats around the centerboard trunk. And the mast compression post (pvc pipe) is also buried in the foam.

Spray foam from home cheapo doesnt realy have any good use on boats. Its too soft and bubbly. Its low density insulation.

I had a similar accident with foam when refilling the motor mount with 2 part foam. I made a mold for the foam to fill in and mixed a and b together. When it looked like it was getting creamy and about to kick off i poured it down the rudder mount mold. What i didnt realize was the bottom has 4 holes for the HIN and the capacity plate. Most of the liquid foam ran out and expanded on the hull bottom. It took a while to break up the gallon of foam. 4lbs density so it was rock solid stuff.

Youll have no problem with that backing plate.

 

[BobbyFunn]

You can't see it, but the first section of it houses the vertical PVC support below the mast step assembly, and then in back of that is the centerboard trunk.

Is there an air gap between the compression post and the centerboard trunk? How much of one?

Im trying to model the 170 on google sketchup and that would be interesting to add.

 

[Rictifyit]

Here's an old picture of the top of the compression post. Sorry, can't answer your question about the air gap because this is all I could see when I had it opened up, before I added the oak plate. There was one crack/hole, just aft of the mast tabernacle where it steps down about an inch. It seemed hollow, so there might be a small amount of air there. It seems that often there were voids where the Luran curved around a corner. I think that would be all though. The rotten wood I took out reached nearly all the way back to that place it steps down, and did have foam in back of it. I filled the hole up with MA, and moved on.

Yes, there probably is wood under the cleat, nestled in foam. I didn't think of it being hidden from view, from the inside. thanks

I wanted the spray foam to create a nest for the epoxy. It barely held the Rot Exterminator, as I had to add cellophane to the top of it to it from leaking out the bottom. I didn't create a nice nest of foam. I created a mess. Great story about the 2 part foam leak you had. Love hearing about "learning experiences" !! That must have been very difficult to remove!

Off to mow the lawn, then to goof off for the rest of this weekend. Stay tuned, and thanks again for your support and advice! Really is great learning all these tricks!

 

[Rictifyit]

@BobbyFunn Hey! I'm nearly done with the Frankenboat! Thanks for pushing me to use a backer plate. This thing is solid now! The butyl was just to stop up the gaps on the side of the plate. To make it fit nicely, and perfectly flat against the biaxial, I sucked it up tight with fishing line, and then injected thickened epoxy to take up the gaps, and wobble.
I have to fix a 1' rip in the jib, and then rig it all up in the driveway.
Hopefully, barring any setbacks, I'll be sailing this thing very soon!
Thanks again to everyone who helped me !

 

[BobbyFunn]

That looks great! Nice work . Next season Ill remove a couple lag screws and inspect that same location. Nice to know its pretty simple once you get past the new 6" hole. Ill put a marine glove box there instead of an access panel.

 

[Rictifyit]

Cheers!
A marine glove box would be a super idea for taking advantage of that hollow space! Only drawback is that I will then have boat envy.
The Stemhead repair was pretty simple, but not easy. Reaching it from a hole in the cuddy put me in contortions! A smaller access hole would not have worked, so a larger one, like that of a glove box would likely make the job easier.
Other challenges occurred, but nothing serious for a smart, flexible, younger man!
Fitting something flat to the curved bulkhead of the cuddy was tricky, and took extra MA to fill in the gaps. I chose MA because I didn't want to promote more cracking from a weaker spot caused by an adhesive that doesn't stick to Luran well. 5200 would stick ok, but it stays flexible.
Needles to say, I learned a lot!
If it all holds together this season, I might even paint it next year!
But I kind of like the Frankenboat style now!
Good sailing!

 

[ehallvt]

Thanks to BobbyFunn for pointing me here, as I am about to embark on a similar adventure: stem head screws pulled up, and when I went to replace the stem head (showed some wear and stretching) the screws would no longer bite. I noticed elsewhere in the forums that the H18 has what looks like an 8" inspection port in the cuddy just like what you created, and I guess I have to hitch up my suspenders and give it a try. I have been using West GFlex 655 for my crack repairs with good success but am still learning the array of adhesives mentioned and perhaps you can help clarify: You would use 3Ms 5200 sealant between fixtures and decking, correct? And what is the "MA" material you refer to? I will post my own adventure once I get there... thanks!

 

[BobbyFunn]

MMA

An Introduction to Methyl Methacrylate Adhesives (MMAs)

Learn more about what MMAs are as well as their applications and advantages.

www.gluegun.com

 

[Rictifyit]

@ehallvt Just returned from a week of sailing in very Northern Wisconsin, so no internet. @BobbyFunn is correct, Methacrylate for crack repairs is the preferred adhesive. The www.gluegun.com information looks good, and at a good price ! It looks like they also offer MA from Infinity Bond Adhesives | Buy Better Glue for Less
which is the company that I bought MA from. Differing MA products have differing handling time before they "go off", so choose what suits you. I found MMA330 from Infinity Bond suited me the best because I am a slow worker, and needed the handling time. 5200 is not for bedding hardware in my opinion. I used Butyl tape. 5200 is messy, and takes forever to cure, unless you use Fast Cure, which has it's own drawbacks, but it sets in 24 hours. Butyl Tape for bedding can be used immediately. Remember, you're not gluing down the stem head, you will be screwing, or bolting it to the boat, so you don't need adhesive, you need sealant, and butyl tape was preferable when I fixed my stem head. BobbyFunn talked me into using a G10 backer plate G10 Fiberglass Board and I'm glad I did. If your screws don't bite, I'd use a backer plate. If your boat has an 8" inspecton port in the cuddy already, you're ahead of the game. The port I put in was 6", but 8" would make it easier. Hope this helps!

 

[BobbyFunn]

Just helping out. Lots of smart mma experts here in the 170verse.

I have never used the stuff other than a thin tube for the rudder mount. I dont have the cracks on my hull that most owners suffer from. I bought a slow cure 50ml tube and the gun a year ago for the extreme deck and bench repair. Its been a year and havent had to make any repairs other than swap out telltales. The 3 different epoxy systems havent formed any hairline cracks on the deck or the benches. It went through all florida seasons without separating away from the luran edges. Thats why i bought the MMA, but no use yet. The original repair manual has us using plexus so its been out for a while.