27 June 2023. Plywood cruisers are only good for ignorant and sentimental people.

[@nathanahubbard1975]

I've seen you using divinycell for years now, and I never really thought about that aspect of it. I assumed it was easier to shape and better insulating than plywood, but I did not realize it could be so much stronger. Excellent video.

[@cornishhh]

Tim and Pauline Carr spent five years living year round in South Georgia; next to Antarctica. Their boat was 28ft and similar to the boats that the Pardeys sailed. The difference was the thick wooden hull was covered with a fairly thick layer of concrete. I don't know how they heated the boat beyond whatever they used for cooking but they obviously survived and stayed healthy. They cruised for over thirty years in the same boat. I agree 100% with the benefits of a thick foam hull, but for many people cost is an important factor.

[@SvenYrvindExlex]

I have read their book but it is many years ago. Letting a hundred flowers blossom and a hundred schools of thought contend is the policy for promoting the progress of the arts and the sciences as Chairman Mao says. I like to open peoples eyes to the good qualities of cored construction then they can make their choices. Still I belive that a 20 feet sandwich construction boat would have been even cheaper. I spent an winter on the Falkland islands with a girl in an 19 feet boat 1980. The boat was plenty big for us two.

[@cornishhh]

@@SvenYrvindExlex If I remember correctly Curlew the Carr's boat was built before the first world war and would have been a cheap boat when they started cruising around 1970. I believe the concrete skin was added partly to give the boat a bit more displacement but mainly to help hold the hull together. When they stopped sailing somebody bought the boat with the intention of restoring it. I think they removed the concrete, but that is the last thing I remember. I don't know what happened after. I used to live on a beamy 21ft boat ( a Hartley TS21) with a long cabin and small cockpit. I found that was plenty big enough for me.

[@braithmiller]

Good sermon. I am also known for sermons.

[@ralphwatten2426]

It's clear that building materials for houses and cars and boats have come a long way over the centuries. From straw to dug out trees to strips to to steel and aluminum and concrete fiberglass and all of that, boat building has changed over time. It's pretty clear that a stiff closed cell foam is the way of the present. What's in the future. It's still in the future. What I like about the Sven Yrvind KZbin channel is how the ideas for the use of the product modifies as time goes on. He uses his head to try to make things work. I don't agree with him some of the time but I'm not a boat builder and won't be floating around the world in something I've built. It's clear that the boats he's built in the past have worked. Kiwi ice cream. Sail on Sven-

[@alexd7466]

next step is probably graphene enforced materials, but it is still a bit expensive.

[@melinda5777]

I totally agree!

[@grantbratrud4949]

I think we can rule out rammed earth boats, or straw-bail construction....

[@LEGOWENTV]

Insulation is something most people won’t appreciate until they need it, I assume. Those pushing back probably haven’t need to deal with that. However…laminating both sides of plywood would dramatically increase durability if that is a concern, but yes…insulation is solved with foam.

[@calanmacleod3948]

All good information.

[@astrayalien]

Thankyou Sven, when you speak the smart men listen.

[@Philippe275]

Well, did you have any plywood boats sink or be damaged because of its 'weakness' ? maybe this composite material is stronger, but maybe it isn't needed and plywood is cheaper and natural.

[@liamstone3437]

So Sven. If I were to build a Goat Island Skiff with foam instead of 6mm plywood, how thick would the foam need to be do you think?

[@melinda5777]

Captain Sven, you amaze me!!

[@thomasduby728]

Good technical talk. I’ve been thinking of building a plywood sailboat because I’ve found proven DIY plans. I have been considering adding glass to reinforce it, but if I did that, I’d have to add it to the inside to Jeep the strength benefits. Are you aware of a good boat designer who has done DIY plans for foam and fiber composites. Note that I have also considered adding a 6mm layer of foam covered with epoxy and glass. I was thinking that would maintain the design intent structurally, and add the impact resistance to the exterior. I would have add add weight to compensate for the extra buoyancy which I could easily calculate with the software and models I have available.

[@SvenYrvindExlex]

I think that you can build a foam sheet boat on a plywood design. Do not make it complicated with many layers. I do not think a 6 mm foam layer will do much benefit.

[@thomasduby728]

I like your experiments. I could repeat them with the 6mm foam with glass and epoxy, over plywood. Might be interesting. I’ll think about that some more. You used pretty thick foam so your probably right about the added benefit of this.

[@superwag634]

Excellent info on materials. But the cost gap is very large. There are better materials than foam. It’s called aerogel but the cost is astronomical. But it is used in spacecraft. Next boat, aerogel exlex 😆

[@BlueChrome]

Err, yeah, but silica aerogel dissolves in water, so don't let it get wet, ever. 🤪

[@MicrophoneMichael]

Hi Sven, I’m looking for a good Divinycell supplier. Does $800 US sound pretty average for the 48x96x2 inch sheets?

[@theresnobodyhere5778]

i dont think using plywood is an issue ,but for safety it requires multiple air watertight compartments all separated to limit the flood volume of water ingress,so the boat would never sink when holed and the others would give buoyancy but you loose storage space and yes there is still no insulation in this method

[@markgamble7699]

Curious if marine plywood would even be ok… Boats all around here though it’s lakes and not oceans seem to love this plywood… Great to see the learning on your wood choices Sven…

[@danno1111]

Marine plywood uses materials (ie wood and glue) that are rot/water resistant, not stronger than high quality plywood.

[@markgamble7699]

@@danno1111 makes sense thank you

[@markgamble7699]

@@skaraborgcraft true

[@funkmunk28]

​@skaraborgcraft material selection should come down to where and what the boat is used for. If you want maximum strength, carbon on foam in a vacuum infusion system is the way to do it.

[@keithweaver7984]

Sven, please can you tell me when you think your boat will be on the water?

[@SvenYrvindExlex]

With some luck next year.

[@boooshes]

It's good to pay attention to people who have real experience like Sven. Designs are the best when they are purpose-driven. Here, Sven has come to some strong preferences on hull construction for his intended use (global cruising). Specific design and construction can't usually be universally applied. If you will only cruise in temperate areas or seasons, thermal insulation is not a design driver. On the other hand, if your construction skill is low, the foam composite may be easier. There is also the danger of misappropriation of techniques and materials - fir instance, there are many foams out there that are incomparable to the divinycell and should not be substituted for it.

[@roanjovitaro9013]

Dejligt med kort god info om materialer 😊men hvor i Danmark købes divinycell

[@roanjovitaro9013]

Tak for din gode råd om styrke .

[@anthonyferreira9059]

Sven new method of fiberglass + foam + carbon fiber is the best method. NEVERTHELESS, many don't have access to it. That is why plywood can be a solution to make a boat vs not making a boat, even if of inferior quality

[@SvenYrvindExlex]

If there is a will there is a way. Many may not have acces to it. But meting cruising boats in the ocean cross roads most are 40 -50 feet long. Most of them could afford a sandwich constructed boat built. But life is like that I have myself sailed wooden boats for decades before using sandwich. In the 90-s I sold drawings collobarating with Rolf Eliasson 10 - 20 boats where built using this method. A few of them sailed to the Carrabian. The where definitely not rich people. One was a taxi driver in Brussels one was a house painter one a jazz musician and his tram driver wife.

[@bockerbob6137]

What about chemical toxicity? I head that some plywood has Formaldehyde. Are there any similar downsides to using foam core?

[@SvenYrvindExlex]

Poison is everywhere but as Paracelsus: It is the dose that makes it a poison. Even some wood is poisinous.

[@JanMeerbeek0304196]

In one of your previous videos you explained that you experimented with Polyester fiber cloth and epoxy! You mentioned that this polyester fiber was used in decksails and was very strong. You also mentioned that is was not easy to handle with expoxy and you changed to glasfiber again. I have some questions , under what name can I buy polyester fiber cloth what weight and what braiding do you siuggest for a bat like yours ( only outside I understand) And last but not least, where do I have to pay attention to when I use polyester fiber cloth and epoxy with foam core.

[@SvenYrvindExlex]

I got mine from Dalsjöfors Väverier here in Sweden. That was in the 1990-s I do not think they have it anymore. It was great as it came in 240 cm with. I recently noticed that North Sails do 3D-sails glued with polyester, Dynema and other fibers. May be the can sell polyester suiteble for gluing. Also builders of white water canoes sometimes use polyester fibers in the layup Try them also. The fibers was easy to put on and drape smothly with no cutting but they had spin oil in them making it difficult to wet out.

[@JanMeerbeek0304196]

Thanks, this will help! When I get a solution for the spin oil I will give polyester cloth/epoxy outside, foam and glasfiber epoxy inside a try! ( and do some tests with it!)

[@NA-su3jk]

How does divinicell ( no extra glass/epoxy) react to a nail being pushed in? Just curious how pourous or hard it is to pressure on a very small point vs wood? Can you push a fine nail into it with no effort by hand - or is a hammer needed? Tx

[@SvenYrvindExlex]

Divinycell comes in many different densities, from 60 kilo/cubic meter to 400. 80 kilo I use for hull and deck. In that density no problem . I use 200 kilo for the rub rail then I use a hammer. 400 kilo/cubic meter is tugh as some wood. Great stuff.

[@cornishhh]

Does anyone know what sort of foam Yann Quenet is using for his rebuild of Baluchon?

[@nasseemmuttur778]

I think he is using plywood.

[@cornishhh]

@@nasseemmuttur778 He put some foam on the cabin sides to cover where the windows used to be. I'll have to keep looking at his videos to see what he uses elsewhere. Unfortunately I don't speak French very well.

[@nasseemmuttur778]

@@cornishhh, he put expanded polystyrene to cover the cavity of the window. On the inside he used plywood. Glassfibre on top the polystyrene.

[@cornishhh]

@@nasseemmuttur778 Ah...thanks.

[@pozorene8772]

Bonjour Sven, Que pensez vous de la construction de Perry Eubank, qui utilise une epaisseur bien moindre que vous. Pensez vous que l'epaisseur qu'il a choisi est plus solide qu'un contreplaqué de même epaisseur ? C'est à dire 10 à 15mm.

[@SvenYrvindExlex]

Diffecile a dire. Sulement test avec une grande marteu donne le correct repons. Je pense que la construction du Perry est asse solide mais ju aime une plus grand marge du erreur Moi choisir 30 mm plutout pour insulation ce important pour moi parsque que je aime navige tout les saison aussi dans les froids mais aussi parsque je aime le bateux costeu.

[@pozorene8772]

@@SvenYrvindExlex merci pour la réponse, nous avons bien compris que la sécurité a une grande importance pour vous. Soignez vous bien, et encore merci pour toutes vos vidéos. 👍

[@mattiasolofsson654]

How strong is the divinycel in the joints?

[@SvenYrvindExlex]

Joints is not a weak point on a sandwich construction. The core is just like a spacer of the skins.

[@NA-su3jk]

Are you building w polyester fiber on current boat? I think i recall you're using glass fiber now? If so - why not polyester as this video argues? Ty for clRifying

[@SvenYrvindExlex]

It is now mostly 450 gram/ square meter biaxial glass

[@AaronBrand]

Darn. I guess I can’t use plywood on my next boat. Although I am a sentimental fool who probably won’t go out in the ocean.

[@AM-es5up]

😎🤘

[@troyboyd3100]

Great video! For all the haters, please keep in mind that Yrvind is not speaking in his native language. I'm sure he did not mean to offend, and was just referring to people who might not be aware of the load testing and science behind his suggestions. How would you do, if speaking in a language that is not your first?

[@gregknipe8772]

what's the difference between ignorance and indifference? I dont know, and I dont care.

[@cortical1]

That title! I love the spunkiness. Keep on keeping on, Sven Yrvind. We support you.

[@borys2767]

I think people forget you are building a sailboat not a submarine.😅

[@NA-su3jk]

I think this is the key video related to using this foam vs plywood, in case anyone not well versed is seriously thinking of switching from ply to sammich: kzbin.info/www/bejne/m5vNpaNoq6tqodk

[@viddywatchin]

maybe it’s just me but seems like your english was better today. in either case, more sermons please. 🙏

[@lorenzom7237]

Pity that there are too many rules attached to build a boat like yours following the law. That is absurd to me. Thank you for sharing your experience.

[@SvenYrvindExlex]

I am not aware of any rules for a home built boat

[@alricmarchand2877]

Yrvind, I respect your work a lot but I must say I was a bit pissed off by your opinion on plywood. There is a place for plywood in boat building. The design envelope is definitely not the same as what you are trying to achieve with a high latitude invincible cruiser but some have successfully designed superb boats for other types of navigation. One of my favorite design is the Corsaire by frenchman Herbulot. I am a designer and I would like to remind that a design is the fruit of an economical context as much as (most times more!) the right technological solution to an intended use. Furthermore, one thing that I never see you mention is the life cycle of your boats. How in the world do you think your boats could ever be recycled? Composites are a superb material, as you rightfully proved, except when we look at the big picture. A material that ends up as landfill, as strong and amazing as it is, is not a good material. So, we can agree that, for your economical context (budget+building time+facility) and if we don't look at the pollution your boat will produce down the line for hundreds of years, yes, composite is the best. Plywood is not just for ignorant, is a design choice. And by the way, being sentimental is not a bad thing :)

[@SvenYrvindExlex]

I know of the Corsaire and I think it a good boat for its purpose. However I do not think it is suitible for a sail through the roaring forties. I am developing a new design. The Idea is that it will not have a short life span and end up in a landfill. The video is is for a high latitude all season small cruiser. Thats needs insulation. If you use the insulation as a sandwich core it will be much better for the envirenment then using plywood and adding insulation. This method makes it possible to use a small boat. In total the damage to the environment is only a fraction of the plywood version

[@grunwode]

Sweden builds for war.

[@Antipodean33]

Plywood was what enabled this bricklayer who had zero wood working experience to build his first kayak. Because of it's price I could take a chance, in case I didn't have the skills I wouldn't be too much out of pocket. Id never done lofting, scarf joints, or worked with glass and epoxy, but I learnt a lot and am on my 3rd boat now. Although my kayak and boats, which are just 14 foot open dinghies for fishing in our rivers and coast line) plywood with glass and epoxy and perfectly strong enough for those boats. Then you talk about things that are not good for the environment, I'm unsure how or what Divinycell is made of but i'm fairly sure it wouldn't be environmentally friendly, in fact it's probably bad for the environment. Insulting people by calling them ignorant, when you seem to be a hypocrite yourself talking about the environment, when you've built boats and are building another boat that is full of shit that is bad for the environment is the height of ignorance

[@SvenYrvindExlex]

The video is not about kayaks for fishing in rivers. It is for a high latitude all season small cruiser. Thats needs insulation. If you use the insulation as a sandwich core it will be much better for the envirenment then using plywood and adding insulation. This method makes it possible to use a small boat. In total the damage to the environment is only a fraction of the plywood version

[@Antipodean33]

@@SvenYrvindExlex plywood grown for the purpose of making plywood is good for the planet, much better than Divinycell