Hi Jon, great video as always! A note on ply how I know it. Hydrotek and Aquatek use Meranti from the Philippines and are of slightly different quality. Then there is okumé from central Africa. Then there is high quality Sapele plywood from west Africa. Some variations are for beauty in interiors only and use an okume core but sapele sides. And of course you know teak plywood. All these are also available for boatbuilding in Europe. What we don’t have as readily available is marine Douglas fir. All of the above mentioned ply’s have quite different characteristics and weight. Other interesting options for race boats are honeycombs made of aramid fibers or Aluminium from many different brands and I might also mention that foam cores can also be supplied with kerfs mounted on a grid similar to the balsa when more curvature is required. Curious to hear what you chose. The winner seams clear to me:)
Hi Aladino. Always great to have your input over here as a master craftsman and shipwright! You make good points about the variety within the "Marine Ply" world since BS1088 does not specify the species to be used, only that it is "durable heartwood" - I'm paraphrasing here but invite anyone to look up the standard if they are curious and reading this... I sort of took an average of various plywood numbers (which are hard to find by the way). I hope that you approve of my choice... the pressure is on!! Haha.
Phone book? Haven't seen one of those in ten maybe fifteen years. Did you get it at an antique store? If I was doing this project I'd go Divinycell with one of those high density materials in areas of high loads (windlass, winches, cleats, deck stepped mast). Remember the stingy man pays twice.
Very well done Jon! Excellent educational video! Looking forward to the process. I am grateful to have joined your project and my guess is this channel will be hugely successful!!! Great job putting it all together!!! Hats off to you sir!!!👏👏👏👏👏👏👏
Thanks Peter. So glad to have you onboard for the project. I’m glad that you found it helpful and I appreciate the support and encouragement as always. 🙏🙏🙏👍👍👍🙌🙌🙌
There are other considerations you may want to consider. Balsa has exceptional bonding characteristics and is the easiest to use. It does not require vacume bagging to get a decent bond like most of the other cores. The problems with balsa are more about it's misuse than it's choice as a core in my opinion.
I don’t disagree with you. Bob Perry even said to me that balsa is hard to beat but he’s not using it in his recent projects as far as I know in favor of good foam products. I suppose your point about getting a good bond with balsa could use more exploration. With it being small blocks on the sheets it should conform better to lumpy bottom skins (like I have) without bagging and that’s handy. I think you could achieve the same bonding reliability by cutting the foam into smaller pieces but balsa will have a better peel strength ultimately with all of those vertical grains. Thanks for the input. 🙏👍🙌
Great video! Much appreciated research you've done for all of us. My guess for your project is that you'll be going with divinycell for the deck, coosa for under the winches and G-10 under the windlass! 😊
Excellent video. I decided to become a patreon to support your project and learn a thing or two for my own refit! I decided to go with Divinycell as it is affordable and available to me, as well as strong and durable in addition to being water resistant.
Hi Viktor. Welcome aboard. I appreciate that very much and look forward to hearing more about your refit and hopefully we can learn a thing or two together. Divinycell is a great option ! 🙏🙏🙏🙌🙌🙌👍👍👍
What about other plastics for strength needed areas. Like Structural FRP fiberglass sheets, SG-200 , Nylon sheets (hard plastic) , or even delrin where the weight is no an issue? Will these even adhere to the epoxy? Have you ever tried other plastics?
SG-200 looks like it would be good in loaded areas if it bonds to epoxy or poly resins. It’s about half the shear strength of G10 but still very high. I think nylon, delrin and most other plastics will not bond well… or at all. Interesting thoughts though. 🙌👍
Hey, little bit late to the party, but better late then never. At 15:05 you were talking about a video that adresses the epoxy-plugging. I couldn't find a link in the video. Can you post it here? Turns out I've got the same damn problem with my Carter 37. Great videos that you're making here!
Thanks for the reminder! I loaded a video in there where I walk through that process. Thanks for the feedback. Sorry to hear about your issues with the 37. You’ll get it sorted out! All the best!! 🙏👍🙌
Great video!!! I've been doing my own research for a project, and I was surprised by Kerdyn 100 product -- I haven't come across it anywhere. As i am on the East coast, I wonder if the release has been more regional -- I have come across the Corecell 100 on various boat sites and stores. I've pretty much made my personal decision on Divinycell for my project -- now it is just a matter of deciding on the budget (H100 or H200). I've been watching Sven Yrvind's current build, and it's hard to argue with the results he has had over the decades -- I'm just not sure about spending the money for the H200 for an experiment ... if it works though I'll have it for the rest of my life!
Robert, Thanks for checking out the video. My email is in the video description. If you send me an email I will put you in touch with someone that can possibly help you with the decision. H200 would be approximately the physical strength of Coosa at less than half the weight ... Interesting. I wonder what it would cost?? When I spoke to Diab they said that H130 could be used but was overkill and more expensive obviously.
Don't forget about conformability. If you are dealing with a curved deck or hull some stiff core materials will be tough to work with. You might have to cut it into smaller pieces or at least cut deep grooves in it to allow some flexing to conform.
Really well done. It's still hard to beat balsa in my view if, like me, you are faced with a complete deck re-core on a sizeable boat. It's also a bit confounding to me why builders would mix ply in with balsa given the very slight differences in strength but I guess options were limited 40-50 years ago. I had ply inserted in areas where it made little sense. My plan is to stick with balsa and 1708, and use G10 in way of stanchions, cleats, and other loaded deck hardware. Oh, the fun!
Balsa is a fine choice and well proven. I think you have a good plan there. Provided you properly seal all of your deck penetrations (using g10 in those areas = even better) you will have a great outcome. Good luck with your project. 🙌
Great review John, awesome to see you have done some extensive research.I'm thinking foam for your bigger voids and coosa for strength around your deck fittings and chain plates. Nice mate.
The core is 3/4” thick. That’s a lot of very expensive resin… it also has poor mechanical properties when it’s not combined with glass (think of cement without rebar). It would also be incredibly heavy and would make the boat less stable. If you mean, why not drill a bunch of holes in the wet deck and inject epoxy like some do on RU-vid… That’s not actually a repair. Nothing will bond to wet and rotten balsa or ply or the old deck skins. Will it seem more solid after? Probably. Is it as strong as the original design was intended to keep you alive in a storm? Certainly not even close… For me, with goals to go over the horizon, a proper repair is worth the blood, sweat, tears, and $$$. 👍
That’s good to know. I guess in your area there’s enough boat building going on for the big retailers to carry it. As long as it’s stamped 1088 or 6566 it’s all good. Nothing like that around here… Cheers.
The video was well done but I'm glad I'll not need the knowledge. We own a 33 year old IP and apparently they got it right so no need for me to experence the pain of core replacement.
That’s good to hear. I would say this is a part of boat life that you can feel good about skipping. I’m enjoying the process but doubt I’ll look back in 10 years and say… “I miss that boat core work…” 🤣
I am going to make a cover for my boat smaller but very similar to what you have done. And for the exact same reason. Replacing deck because teak and thousands of screws. Curious as to how to make those curved beams. I would like to do the same - but not sure how to bend it.. Even with the thin wood did you have to do something special to get it to bend? Also how thick is the curved wood. Maybe you did a video explaining the process? :-) ... I will check.. Great video by the way.
Very high level but this might help a bit... ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4bG5AauMVf4.html google search "LSU gothic arch greenhouse shed plans" it is BASED on that... The beams are split 20' 2x4 planed to 1/2". Everything is glued and screwed together to make the arches. I made 2 every 24 hours for a couple weeks... I wanted the glue to cure before pulling them off of the template but that might be overkill... Good luck!!
@@livingforsailMany thanks for the tip! I actually plan to make a storage unit behind my garage as well.. So that build can be my practice run. Then I will do the same ( or something similar ) at the Marina. Again thanks for the tip. Come June 1st I quit work to start on this. Am very nervous .. but it needs doing. BTW: I have a Cheoy Lee Midshipman 40 - 1975.
I own plywood 24ft trimaran. I used epoxy primer for plywood deck + epoxy topcoat. It needs painting due too esthetic reason but it works fine as an water insulator. If I had come back in time I would have used polyester topcoat instead.
@@livingforsail No, actually. Topcoat is the final layer. Epoxy topcoat has one disadvantage - it doesn't sustain sun in a long run. By now my deck which was covered with topcoat has faded. Poly is UV resistant.
No reason. It looks like a good PVC foam option. I think it’s from Switzerland. I’m not sure how the distribution is in the USA where my project is. It didn’t pop up as an option that was available easily in my area.
I learned a lot Jon. Thanks. The different kinds of plastic foam core seems to be the obvious choice because water has little effect. That is, if money wasn't an object. But it is for most of us. I'm sure it's a consideration for you. If it wasn’t, you wouldn’t be restoring an old boat. You would have purchased a new boat for $500,000 dollars off the showroom floor. Marine grade plywood will last lifetimes if you prevent water intrusion. But aye, there is the rub. It's a boat. Still Maya and Aladino on Sailing Magic Carpet ripped the fiberglass off their plywood decks. The decks held up well even after 50 years. My bet is it will hold up well for two hundred years. But they didn't have hundreds of deck penetrations as a result of screwed down teak decks.
Yeah. Marine grade plywood is a good choice if you can be confident that water won’t be an issue. As you’ve already pointed out… difficult to do on a boat! I don’t think I could ever bring myself to buy a new boat even if I had the money and as I continue down this path of making RU-vid videos and quitting my engineering job I assuredly never will in the future either 🤣. Thanks as always for the input!
thanks for the reply and advice. Ok, i'll do the job by replacing the core vs waiting 10 yrs fand end up w/ a poor core afterwardes. I do not think I have that much time left.
That’s more common for filling molded parts like a rudder for example. It would be a challenge to get an even core thickness with expanding foam for a deck.
Pretty sure my deck is solid fibreglass , why not thicken up the deck with epoxy/glass or does the thickness for fittings come into it like hatches ? Great video and wish you would explain how you got those curves perfect for your shelter build infact a video on that would be really good. I guess you used a jig of some sort.
If your boat was designed with a solid glass deck then that’s great. Trying to convert a cored deck to a solid one is not really practical since I would need to add 3/4” of solid glass. It would be way too much topside weight (and cost a fortune). The shed frames were built on a jig on the ground. I have some video of it that I may put together at some point but I was in a mad rush since the birds were already flying south and the storms were coming!!
@@livingforsail I reckon mine is only about 3/8” 10mm thick and it’s so solid, it also has a fibreglass inner mould for the interior which is perfect gelcoat..Sadler 26 UK boat , twin skin hull closed cell foam fill so it’s unsinkable I don’t like these cored decks especially wood or similar in there , it’s always going to hold water
Very nice presentation, thank you. If you choose to use G-10 on your project, I highly recommend that you invest in diamond blades for your tools. G-10 will destroy carbide tipped blades in short order but diamond blades work great. They are readily available at your local box store for table saws, circular saws, and jig saws.
@@livingforsail I learned that one the hard way making a 12” long table saw cut in a 1” think piece of G-10 with a brand new carbide tipped blade. That was all it took to dull the blade completely. The diamond blade will make clean cuts all day.
I'm planning on building a lightweight 12 foot tender and putting a 20 hp outboard on the transom. I was thinking of using foam sandwich between carbon fiber. What would you recommend?
A lot of people use Coosa for transoms. It’s still reasonably light. Carbon and 10lb foam would certainly be lighter. I think you’d really need to get your design reviewed to make sure it’s stiff/strong enough if you’re going for “as light as possible” Good luck!
@@livingforsail I've got the design. It's strong enough to handle rough chop while pushing it with a 20 hp at full throttle for hours on end. That Coosa sounds like the perfect material for the transom and foam for the rest. Would you recommend using foam with little holes in it so that the resin flows through connecting both sides or would that not be a good idea?
@@robertlaird6746 The holes in the foam are primarily there for allowing resin and air movement if you are doing a vacuum wet layup (some holes) or infusion (many holes). If you are just doing a traditional wet layup then you don't need any perforations but if you have some, it will still work fine. That is my understanding from the manufacturer of the foam that I am using.
@@livingforsail Will the manufacturer guide me in the direction I need to go as I have never tried vacuum wet layup or infusion. I'm thinking of doing vacuum wet for the hull itself and then for everything else, traditional wet for the most part anyways. Also, what size of holes should I use or drill out and what spacing? Also, what thickness of foam for the hull?
@@robertlaird6746 I would put a call into the folks at DIAB (makes or Divinycell). They have some tech experts that can likely help guide you. I have also found good help from the folks at Coosa on the phone.
Well thank you kindly for the feedback! 🙏🙏 This video is a bit more “dry” compared to the usual refit videos. I do plan to make some more “tech talks” like this as I progress through the refit. I hope that you find something enjoyable about all of the videos. 👍🙌
Corecell has been around at least since the early 90s. I'm buying a boat made by Cabo Rico in 1993 built with Corecell. This is very good stuff. It has a high resistance to impact.
Thank you! 🙏 XPS doesn’t fair so well with peel strength. Not something that I explicitly scored. It would probably work (with epoxy). I haven’t heard of too many structural components built with it though… great for the ice box though!! 🙌👍
In Denmark we tend to use Okume plywood - also called Marine Plywood. It is not common in "regular" stores, and many "regular" stores tend to misinterpret the difference of another material named "oesten" plywood, but there is a world of difference. If you do not want to go with Plywood for the deck, the light foam is in Europe name Davinycell, and is extremely easy to work with as it is very flexible, and holds no water.
Hi. Thanks for the feedback. We have a few varieties of marine ply in my area (mostly imported from overseas). You’re right that some “marine” ply’s are deceptive. Best to look for the official stamp! I actually did decide to go with Divinycell H100 for most of the deck and you are right about it. Great stuff!!
I just found your channel and subscribed. I took a look at your first video and I'm blown away by how much your story mirrors mine. Like you, when I was a kid, I had a dream to sail the world but I got sidetracked with the corporate world - I am a lawyer, and raising a family. When covid hit all the courts closed and I was basically ideal for the first time in my life. That gave me time to reevaluate my life choices and I found I wasn't very happy with how things were going. At that time I stumbled upon a project boat, a '72 Formosa ketch, and to my surprise my wife "ordered" me to buy it. 3 years later, I have a full beard, long hair and I haven't worn a tie since 2020. I've replaced the entire deck, restored the wooden masts and rigging, and basically gone through the entire boat inch by inch. This next spring I'm sailing her for the first time, from Oregon to her home in California. BYW, your video was very helpful.
I LOVE IT!!! Well done sir, and hats off to your wife as well for encouraging (or ordering) you to go for it. This makes my day. Thanks for saying hi and for the feedback. Cheers! 🙏👍🙌
Fantastic video! Your breakdown (and graphics) of the material options and their qualities are really helpful. And you prove the cosmic principle that there are no perfect solutions only variables and trade-offs. Thank you!!
Thank you. 🙏 I’ve seen the videos where people drill a bunch of holes and “dry” the deck before injecting a bunch of epoxy into old rotten decks. It might provide more stiffness but it is not a REPAIR in my opinion. I recently saw some pictures of a deck being replaced after a previous owner attempted this “fix” and he was removing all these little clumps of epoxy barely stuck to rotten balsa. It would probably take 10 years for a deck to dry out naturally with a bunch of holes drilled and even if the balsa/ply dries, if it’s started to soften and rot, it’s not much good anyway… Yes, it takes longer to replace the deck core but it is the only true repair (my opinion 😉) Cheers!
I’m not a if fan of MDF in general but this is an interesting product that I didn’t know about yet. They don’t report shear or compressive strength and I’d be suspect about the ability to resist shear in particular. Also a bit heavy… have you tried it in this application?
I have it build in my transom in a Phantom 21 with a Merc 275 Verado Supercharged behind. 3 layers of 18mm that is very strong and not superheavy. And because i wanted the boat to be as light as possible that was important too. Love your info. Keep on sharing please.
Insects...yes. Termites got into my boat that was parked on land for 8 years and completely made the wood in the transom disappear except for a small handful of hard flakes. They built mud-tunnels behind the cabin-liner and my fiberglass decks are springy so I assume they ate the wood core there too. But it's fun to rebuild it all better than new so I'm happy.
It’s a great question. Unfortunately the diatium power source was depleted during the last test and I can’t seem to find a compatible charge cable… before I try a backyard hack, does anyone out there by chance have one?? I don’t want to void the warranty… 😜
Haha 😂 Whatever core is used it will out last him.Probably be under the building for 10 years at the rate he’s going.putting all this back together takes way longer then taking it apart.Choice do a good job and go sailing or do it the very best and going sailing in 5 years or longer.even marine plywood would last longer then he will live.I don’t think insulation is important especially with no Ac.Cost is always important and availability is important.The heavier the core is the strong it is,Coosa is the best!Coosa is lighter then plywood but heavier then some cores.3/4 Coosa is $350 for 4x8 sheet.Very nasty to cut and sand but very strong.Coosa by a mile on that heavy bluewater sailboat
Ha. I appreciate what you intended but like Jon’s sister and being his father, you will learn that there are some people you never say ‘never’ to. Jon L. Congo is one. You WILL see.
Fantastic review! We went with Nidaplast on our recore for cost purposes, we haven't noticed any compression issues with the sections we have already replaced, the deck feels 100% more firm than the old balsa we had.
