Impact resistance was always my biggest concern with foam. Thank you for sharing your experiments. Now that I know the impact resistance is better with polyester fiber, I will not go back to plywood hulls. Can you share your layup schedule for this boat?
This boat have glass 450 gram 45°x45° Three layers on topsides up to 16 in bottom for ballast and strong bottom to take the ground when tide goes out. Inside will have one layer carbon 600 gram 45°x45°.
If I have understood, it acts like striking with a hammer a washer on a substrate: the wider the washer the less it penetrates. The fiberglass can break under an impact and the part of fibreglass that detatches from the skin of a sandwich construction penetrates into an underlying core and acts like a washer pushed on the substrate. In the case of polyester tissue being this one far more elastic, instead of breaking, it stretches and distributes on the adjacent tissue the force of the strike, acting like if this time the force of the hit is being on a much wider washer. At least it is like I imagine it works.
Information like this is super important. Thank you so much for sharing this. Experience and knowledge like this, gained by someone over time, is often just lost in time. Thank you for putting it in a video!
Yes, I like your new boat to be super strong,Sven! To be able to deal with super strong winds/ bad weather, and to survive hitting a stone sticking up! Like the perfect off grid boat!
That's incredibly interesting. I would also like to ask what resin you are using for glassing the boat? Epoxy resin is significantly stronger and water resistant than polyester resin. It's more expensive, too but I think it's worth the price.
A concrete boat with steel reinforcement is very strong and stiff. The Viking ships were flexible. War ships need to be both strong and flexible so that an impact from an explosion or impact of a bullet doesn't fracture the ship. The same is true for any ship or boat. They need to be strong and withstand impacts without fracturing. The energy form the impact of hitting a rock or a wavy breaking and then striking the ship must be distributed by flexure. The effective energy peak is lower but the total amount of energy isn't changed. So the ship will be lighter and cheaper typically to build if it is more flexible. But the bending of the hull will alter the position or pointing direction which will reduce steering. Steel cables on ships are used to stiffen up a mast that is too flexible and will deflect without steel to it's breaking point, however; the load on the mast increases as stiffness increases. So for racing ships the winches should have torque limiting clutches so that when the force on a sail exceeds the mast strength is never reached since the sail swings to point into the wind. A balance between strength and stiffness.
Or one could use an unstayed mast, allowing it to bend and distribute the forces onto the hull through its partners and step. It must be stronger than a stayed mast, but it's a simpler and safer rig. I really like gaff and balanced lug/junk rigs.
Thank You Sven ! Folks it time to get people to subscribe to these short little clips. His lifetime of mini cruising, boat building experience, and stories are priceless. REMEMBER, " Beyond All Things Is The Sea " SENECA
Hi Sven, thanks for the informative video!! Quick question, I'm totally new to composites so am not familiar with all the terminology. You mention the fabric is polyester fiber and say it is similar to something else and you mention a word that sounds like "tire iron" but I'm pretty sure you're referring to something else. Could you clarify what the polyester fiber is similar to? Thanks in advance and sorry for this novice question! 😅
I believe this foam will act as a fairly good insulator also. I don’t understand condensation very well in boat interiors and how insulation relates to this. Will the insulating properties of this foam result in any condensation inside the boat? Your body creates about 1watt of heat per kg at rest. A human exhales about 1dl per hour of water vapor at rest.
Condensations happens where there is a colder surface. Divinycell 70 mm thick is a very good insulator. Therefore the surface do not get cold when cold outside. Exlex windows I do not insulate with doubble or tripple glass. They get cold; they get the condensation. This means my windows drys the air in the boat. True a human body exhales water wapor, but it does so also in a warm climat and in a warm climat there is no condensation.
Definitely today. A friend of mine spend the summer with wife 2 children and a big dog in a boat 5.4 meter Monark many years ago and no one thought that was strange. Today they like 40-50 feet with shower bathroom and washing machine. Same humans different mindset
Hello! How does it cooperate with other core materials ( plywood for example ? ). You were speaking about compression part of the laminate - what do you suggest for the inside ( tension ) ? Maybe carbon fiber, but it will break at 1% of elongation and this polyester at 17% . This laminate elongation matching is really interesting and would love to hear your empirical opinion.
yes polyester fibre elongates to about 17% and glas to 4%. But if you use 2 times the material of polyester for the same load it will elongate about 8%. A small boat have no problems with global forces. local forces is the problem. Designing the outher skin with many layers of polyester increases the stiffness of the structure but not of the material at the same time makes it more resistant to local forces
interesting,, I wouldnt have thought it would be easy to wet out? and would have thought it behaved similarly to peel ply, not full adhesion? Btw, have you experimented with basalt fibre?? I read some good things about it.
How many layers wood be needed to achieve that strength Sven ? There wouldn't be many production boats built that way they would last too long. LOL Thanks Sven for sharing your thoughts with another video.
Polyester resin lm lead to believe is much more harder or brital than epoxy ? Would using polyester resin on the polyester fibre have given you a different response with the ballpoint hammer ? thanks again Sven for another good one.
Hi Yrvind thank you for another informative video, is this Diolene not the same as used in building very durable Kayaks. In there construction Diolen at 300 gsm can be used instead of Kevlar, is this what you used in the test samples? or thicker perhaps maybe more layers even?. Slainte Tariq
Diolen the poor mans Kevlar. We did use a product from a Swedish company. This was before internet. But I belive its essentially the same. The weaving pattern was different I think. It is used in white water kayaks often combined glass
@@SvenYrvindExlex Thanks for the response yes in Kayaks it is sandwiched between chopped strand mat fiberglass, much cheaper than Kevlar if you do not mind the extra weight. So you only used a single layer? Slainte Tariq Edit: I see you answered elsewhere that you used 10-15 layers, would that be enough for a bluewater boat?
@@TariqKhan-77 Again it depends on the boat and intended use. But I say 10-15 layers on outside is very strong combined with 50 -70 mm Divinycell. If you build that way there is not much you have to worry about except the future of humanity.
I am not sure to understand everything... 10 to 15 layers of Diolen fabric are supposed to replace the glass on top of the foam? Or is it supposed to be combined with glass, as we see on kayaks? Thanks a lot for your answer Mr. Yrvind! Amitiés de France.
If you want an even stronger hull you can use Diolen as outer layer insted of glassfibre. In an sandwich construction you do not need to mix it with glass as the foam core gives the desired stiffness
You have used glass fibre instead of polyester fibre for your last few boats. Would you explain the reason for the switch (perhaps in another video at some point)? Also, I think you mentioned in your book that the epoxy needs similar maximal elongation before breaking as the fibre. But if that greater maximal elongation of the epoxy comes with less stiffness, does the stiffness of the laminate depend on the stiffness of the resin as well as the fibre? Is it possible for the epoxy to be too elastic?
I say my use of glass fibre nowadays is mostly lazyness combined with that the thick Divinycell makes it very strong. Now I think polyester fibre is a bit of overkill. The greater the elongation the better if it is combined with stiffness. Sometimes it is difficult to get the different materials to fit well. One have to do with what is obtainable. My boats are not perfect
So Yrvind, concluding, what do you recommend for the 'strong boat' from inside to outside: carbon (locally) + Dyvinicel + epoxi + polyester fibre + epoxi (2x)? So, 6 layers.
I didn't completely understand what you said, Sven. Were those boats built with polyester fiber exclusively on both the inside and outside of the sandwich, or was it applied over or under layers of fiberglass? If you were to use it today, would you use carbon fiber on the inside of the sandwich and polyester on the outside over the fiberglass?
Those boats built in the 80-s and 90-s had polyester fibre on outside and glass fibre on inside. With so thick foam 50 - 70 mm you do not have to worry about the inside laminate glass and carbon fibre will be ample.
Back in the 80-it was polyester fiber made to be coated with PVC for tarpulin for lorrys. Not the brand Diolen. Glass on the other hand the type I am used is sized for epoxy. I it was not a big problem also I think it was 240 gram rather thin and we had to use many layers. Not a big problem
Yes, he will have carbon fiber/epoxy inside, then divinycel, then glass/epoxy outside. It's quite a good combination for strength, stiffness, impact resistance, thermal insulation, sound insulation. He also has numerous layers of glass/epoxy on the bottom at ground impact points.
The beam test showed that the sandwich was more than twice as strong. I am home now and have the numbers in workshop. Impact strenght here the foam with polyester fibre showed many times the strenght of the other. No comparison In a class by itself.
@@SvenYrvindExlex Ok, thx Sven it is compleetly clear to me and it looks actualy as a verry smart hull bilding. A lot of people forget that the oceans have more and more rubish that floats, like wooden beams and barrels for instance, that can be verry deadly on impact on a stormy wave. Verry smart bild Sven, also as a good isolation material.
@@KleinDuimpje878 From the 2nd Sep video when the foamcore arrived it is H80 -70mm, you can pause and see it on side of box written, though Yrvind has mentioned it a few times also.
Your a great teacher! Love today's lecture! Thank you!
I love the data/experimental approach!
This is knowledge and experience for future generations. Thanks Sven
The best video by far. A true Engineer ! Nice work Sven. Nice indeed ! yes, I agree...you would make a great teacher ! Thank you Sven!
Thank you Mr Sven for share so much facts colected along a lifetime span, not really often now!!
Impact resistance was always my biggest concern with foam. Thank you for sharing your experiments. Now that I know the impact resistance is better with polyester fiber, I will not go back to plywood hulls. Can you share your layup schedule for this boat?
This boat have glass 450 gram 45°x45° Three layers on topsides up to 16 in bottom for ballast and strong bottom to take the ground when tide goes out. Inside will have one layer carbon 600 gram 45°x45°.
If I have understood, it acts like striking with a hammer a washer on a substrate: the wider the washer the less it penetrates.
The fiberglass can break under an impact and the part of fibreglass that detatches from the skin of a sandwich construction penetrates into an underlying core and acts like a washer pushed on the substrate. In the case of polyester tissue being this one far more elastic, instead of breaking, it stretches and distributes on the adjacent tissue the force of the strike, acting like if this time the force of the hit is being on a much wider washer. At least it is like I imagine it works.
Information like this is super important. Thank you so much for sharing this. Experience and knowledge like this, gained by someone over time, is often just lost in time.
Thank you for putting it in a video!
Thank you Sven. You are a great teacher. Your experience is invaluable.
His works need to be documented, building something to withstand a force like that in a garage is amazing.
Yes, I like your new boat to be super strong,Sven! To be able to deal with super strong winds/ bad weather, and to survive hitting a stone sticking up! Like the perfect off grid boat!
Sven you are a great teacher ⛵️⛵️👍💕
Thank you Sven. Valuable information sir.
That's incredibly interesting. I would also like to ask what resin you are using for glassing the boat? Epoxy resin is significantly stronger and water resistant than polyester resin. It's more expensive, too but I think it's worth the price.
Very interesting! But you could also use kevlar or a mix, fiberglass and kevlar I think!
A concrete boat with steel reinforcement is very strong and stiff. The Viking ships were flexible. War ships need to be both strong and flexible so that an impact from an explosion or impact of a bullet doesn't fracture the ship. The same is true for any ship or boat. They need to be strong and withstand impacts without fracturing. The energy form the impact of hitting a rock or a wavy breaking and then striking the ship must be distributed by flexure. The effective energy peak is lower but the total amount of energy isn't changed. So the ship will be lighter and cheaper typically to build if it is more flexible. But the bending of the hull will alter the position or pointing direction which will reduce steering. Steel cables on ships are used to stiffen up a mast that is too flexible and will deflect without steel to it's breaking point, however; the load on the mast increases as stiffness increases. So for racing ships the winches should have torque limiting clutches so that when the force on a sail exceeds the mast strength is never reached since the sail swings to point into the wind. A balance between strength and stiffness.
Or one could use an unstayed mast, allowing it to bend and distribute the forces onto the hull through its partners and step. It must be stronger than a stayed mast, but it's a simpler and safer rig. I really like gaff and balanced lug/junk rigs.
Thank you Sven.
Thank You Sven !
Folks it time to get people to subscribe to these short little clips. His lifetime of mini cruising, boat building experience, and stories are priceless.
REMEMBER,
" Beyond All Things Is The Sea "
SENECA
Diolen - thanks for passing on this very useful information!
Thanks again for the very useful information
Hallo Sven, really like the boat and the video's, nicely done, keep it up👍
Yrvind knows his stuff!
Great video, thanks 👍
Hi Sven, thanks for the informative video!! Quick question, I'm totally new to composites so am not familiar with all the terminology. You mention the fabric is polyester fiber and say it is similar to something else and you mention a word that sounds like "tire iron" but I'm pretty sure you're referring to something else. Could you clarify what the polyester fiber is similar to? Thanks in advance and sorry for this novice question! 😅
Glad to hang out for a bit thanks for uploading ✌️😎✌️
Breaking a strong boots make strong muscle
Words of wisdom.
Just wondering... what will be weight of the boat when finished? Empty and Provisioned(travel ready).
This video, is one of the best, yet.
I am wondering to. Time will tell. I am hoping for 600 kg empty and 1000 kilo for 6000 mile range 1200 kilo for 10 000 mile range just guessing.
@@SvenYrvindExlex I like the way you plan meticulously but also allow that the boat is a work of art and will inform too.
I believe this foam will act as a fairly good insulator also. I don’t understand condensation very well in boat interiors and how insulation relates to this. Will the insulating properties of this foam result in any condensation inside the boat? Your body creates about 1watt of heat per kg at rest. A human exhales about 1dl per hour of water vapor at rest.
Condensations happens where there is a colder surface. Divinycell 70 mm thick is a very good insulator. Therefore the surface do not get cold when cold outside. Exlex windows I do not insulate with doubble or tripple glass. They get cold; they get the condensation. This means my windows drys the air in the boat. True a human body exhales water wapor, but it does so also in a warm climat and in a warm climat there is no condensation.
Mastrr🎉
7meter long - for a family :D that is thinking outside the box! Great video.
Definitely today. A friend of mine spend the summer with wife 2 children and a big dog in a boat 5.4 meter Monark many years ago and no one thought that was strange. Today they like 40-50 feet with shower bathroom and washing machine. Same humans different mindset
Go to the library. Look at pictures from the 60-s in yachting magazines. You see a lot of happy faces in small boats
@@SvenYrvindExlex
Agree! Big boat= bigger expense and potential for bigger problems!
Do you want own your boat, or have your boat own you?
@@kenwalter867 I have maxi racer 26ft. 7 people is the maximum I have been sailing with :)
@@SvenYrvindExlex Well this only proves my point :) Mind shifted
Were your tests of just polyester fabric and epoxy, or polyester fabric over fiberglass fabric all epoxied together?
The test was on only polyester fabric
Strong is good.
You appreciate it most when a thousand miles from land and angry grey beards do their best to destroy you.
Very interesting! Thx
Hello! How does it cooperate with other core materials ( plywood for example ? ). You were speaking about compression part of the laminate - what do you suggest for the inside ( tension ) ? Maybe carbon fiber, but it will break at 1% of elongation and this polyester at 17% . This laminate elongation matching is really interesting and would love to hear your empirical opinion.
yes polyester fibre elongates to about 17% and glas to 4%. But if you use 2 times the material of polyester for the same load it will elongate about 8%.
A small boat have no problems with global forces. local forces is the problem. Designing the outher skin with many layers of polyester increases the stiffness of the structure but not of the material at the same time makes it more resistant to local forces
@@SvenYrvindExlex Thank You!
Fantastiskt! Är kommer du att lägga ett till lager med laminat ovanpå glasfibret, med polyester?
interesting,, I wouldnt have thought it would be easy to wet out? and would have thought it behaved similarly to peel ply, not full adhesion? Btw, have you experimented with basalt fibre?? I read some good things about it.
No basalt fibre, but one hae to keep ones eyes open
How many layers wood be needed to achieve that strength Sven ? There wouldn't be many production boats built that way they would last too long. LOL Thanks Sven for sharing your thoughts with another video.
It was like 25 years ago so I do not remember but 10 - 15 maybe. Much depends on the boat and what kind of sailing intended
Polyester resin lm lead to believe is much more harder or brital than epoxy ? Would using polyester resin on the polyester fibre have given you a different response with the ballpoint hammer ? thanks again Sven for another good one.
Hi Yrvind thank you for another informative video, is this Diolene not the same as used in building very durable Kayaks.
In there construction Diolen at 300 gsm can be used instead of Kevlar, is this what you used in the test samples? or thicker perhaps maybe more layers even?.
Slainte
Tariq
Diolen the poor mans Kevlar. We did use a product from a Swedish company. This was before internet. But I belive its essentially the same. The weaving pattern was different I think. It is used in white water kayaks often combined glass
@@SvenYrvindExlex Thanks for the response yes in Kayaks it is sandwiched between chopped strand mat fiberglass, much cheaper than Kevlar if you do not mind the extra weight. So you only used a single layer?
Slainte
Tariq
Edit: I see you answered elsewhere that you used 10-15 layers, would that be enough for a bluewater boat?
@@TariqKhan-77 Again it depends on the boat and intended use. But I say 10-15 layers on outside is very strong combined with 50 -70 mm Divinycell. If you build that way there is not much you have to worry about except the future of humanity.
@@SvenYrvindExlex yeah, future of humanity would need some more layers
I am not sure to understand everything... 10 to 15 layers of Diolen fabric are supposed to replace the glass on top of the foam? Or is it supposed to be combined with glass, as we see on kayaks? Thanks a lot for your answer Mr. Yrvind! Amitiés de France.
If you want an even stronger hull you can use Diolen as outer layer insted of glassfibre. In an sandwich construction you do not need to mix it with glass as the foam core gives the desired stiffness
You have used glass fibre instead of polyester fibre for your last few boats. Would you explain the reason for the switch (perhaps in another video at some point)?
Also, I think you mentioned in your book that the epoxy needs similar maximal elongation before breaking as the fibre. But if that greater maximal elongation of the epoxy comes with less stiffness, does the stiffness of the laminate depend on the stiffness of the resin as well as the fibre? Is it possible for the epoxy to be too elastic?
I say my use of glass fibre nowadays is mostly lazyness combined with that the thick Divinycell makes it very strong. Now I think polyester fibre is a bit of overkill. The greater the elongation the better if it is combined with stiffness. Sometimes it is difficult to get the different materials to fit well. One have to do with what is obtainable. My boats are not perfect
So Yrvind, concluding, what do you recommend for the 'strong boat' from inside to outside: carbon (locally) + Dyvinicel + epoxi + polyester fibre + epoxi (2x)? So, 6 layers.
Depends on the boat and the sailing intended, but If I remember we used 10 - 15 lyaers of polyester fibre. It was a Swedish brand similar to Diolen.
Plus the foam core
The fabric is polyester dyneem ? Is that what it's called ?
I didn't completely understand what you said, Sven. Were those boats built with polyester fiber exclusively on both the inside and outside of the sandwich, or was it applied over or under layers of fiberglass? If you were to use it today, would you use carbon fiber on the inside of the sandwich and polyester on the outside over the fiberglass?
I believe he said the inside will be carbon fiber in a video a day or two ago
Those boats built in the 80-s and 90-s had polyester fibre on outside and glass fibre on inside. With so thick foam 50 - 70 mm you do not have to worry about the inside laminate glass and carbon fibre will be ample.
Why is laminating Diolen more work than fiberglass?
Back in the 80-it was polyester fiber made to be coated with PVC for tarpulin for lorrys. Not the brand Diolen. Glass on the other hand the type I am used is sized for epoxy. I it was not a big problem also I think it was 240 gram rather thin and we had to use many layers. Not a big problem
👍👍
Is it polyester fibre ?
Yes polyester fibre like Diolen
stronger than Carbon fiber?
More impact resistance
So i'ff i have it right.. That foam is between your fiberglass and it is 2,5 times as strong as plywood???
Yes, he will have carbon fiber/epoxy inside, then divinycel, then glass/epoxy outside. It's quite a good combination for strength, stiffness, impact resistance, thermal insulation, sound insulation. He also has numerous layers of glass/epoxy on the bottom at ground impact points.
The beam test showed that the sandwich was more than twice as strong. I am home now and have the numbers in workshop. Impact strenght here the foam with polyester fibre showed many times the strenght of the other. No comparison In a class by itself.
@@SvenYrvindExlex Ok, thx Sven it is compleetly clear to me and it looks actualy as a verry smart hull bilding. A lot of people forget that the oceans have more and more rubish that floats, like wooden beams and barrels for instance, that can be verry deadly on impact on a stormy wave. Verry smart bild Sven, also as a good isolation material.
@@SvenYrvindExlex what kind of Divinycell foam you use Sven? H, HP, HM, HT, HCP or Matrix?
@@KleinDuimpje878 From the 2nd Sep video when the foamcore arrived it is H80 -70mm, you can pause and see it on side of box written, though Yrvind has mentioned it a few times also.
hur djupa spår såga du?
Different half sometimes more sometimes less