Hi David, I don't really visualize your process, but it sounds like it could be a cool idea. Only way to find out is to give it a try.

Cost-glass is about one quarter of the price.

Carbon/Kevlar is significantly tougher than glass, but I also use it because it looks cool.

western red cedar, fiberglass, epoxy, carbon/Kevlar cloth, and a lot of time.

Kevlar is only strong in tension, it's really bad in compression. Carbon is good all round, especially in compression.

I get mine from Composite Envisions. They have a lot of colors and options.

Great tunes BTW.

+Cheeky Monkees Running across the boat is more efficient with the cloth. It wastes less of the expensive material.

+Nick Schade Thank you for the reply. Does the over lap of mat also create a structural element as well, somewhat like a partial bulkhead or is the result negligible?

Cheeky Monkees theoretically, the overlap creates a slightly stiffer section like a rib.

+Nick Schade "newbie" That sounds logical. Thank you for responding and sharing your knowledge. You've been very helpful. BTW: You have a great website.

Carbon is much, much stronger for a given cross section. So, you can either reduce the weight of your cloth for the same strength of glass, or keep it the same and have a much stronger hull. Remember, most of the weight of a laminate is the resin, so if you can use a thinner cloth for the same strength, you make a lighter structure.

Carbon is marginally stronger, it's just stiffer.

While "most of the time" the kevlar may be in compression, when you hit a rock it is in tension, that is when you care. The boat will be finished bright, so you can see the wood. Kevlar is not transparent. For this application, it would not work on the exterior.

As I said, totally pointless to put on the inside of the hull. Another KZfaqr with no idea on how to apply composites pretending to be an expert.....

I'm glad we have your expertise to set us youtubers straight. The data and cogent arguments you brought to the subject of kayak failure modes are most enlightening. After 30 years of using and building kayaks, I am consistently amazed at how much I can learn from one pithy line from an expert such as yourself.

Nick Schade I'm guessing you've used expert in the traditional sense for this case remembering the origin of the word. "Ex" as in has been and "spurt" as in drip of water under pressure. Appropriate for this "expert". A has-been drip. ;-)

So, Carbon for stiffening, Kevlar for splinterprevention?

sweetcomposites.com/Kevlar.html look at the: Style 94905 or 94956

@@NickSchade thankyou Sir

@@NickSchade what about using this cloth on a Skin and skeleton type of design?

The polyester or nylon fabric used on Skin on Frame boats works differently from fiberglass and carbon/Kevlar. It is not appropriate for this application.

"I Thought About You" by Ron Carter, off Mr. Bow Tie

thank you! love your videos! please make more!

Thank you for your comment. In the process of building these kayaks there are a lot of different decisions the need to be made. While strength is obviously a concern, there are tradeoffs with weight and appearance that must also be considered. As a practical matter, these kayaks are built with a huge safety margin. In order for the weakest link to fail, the kayak has to be exposed to loads and forces way beyond what most paddlers would ever risk. The situations where these kayaks are at risk of catastrophic failure are dangerous to the paddler regardless of the strength of the kayak. I.e. large waves crashing into hard rocks. In this layup we are not using just fiberglass, Kevlar and Carbon, it is all in a stack with wood in the middle, the fiberglass at the opposite end of the stack from the Carbon/Kevlar. The failure mode for the layup is one sided: a hard/sharp object impacting from outside the kayak. In this scenario, the fact that glass and CF have different tensile strengths is not that relevant, as only the CF is in tension, the glass is hard against the rock, in compression. In this layup, the glass adds waterproofing, abrasion protections, surface hardening and tensile strength while being transparent. The wood adds thickness for stiffness as well as its own tensile and compression strength while being light weight and beautiful. Of course the wood has different properties depending on grain orientation. The carbon fiber adds cross grain stiffness. The cloth being used here has the CF running across the width of the boat where it provides the most reinforcement to the wood grain. While the wood needs little reinforcement along the grain, the Kevlar serves to add toughness. If everything else should fail, the Kevlar can hold the bits together while you paddle to safety. Given the strength, weight and aesthetic tradeoffs involved I think this layup works efficiently. My practical experience through 30 years of using these boats hard, bares out that conclusion. While there is certainly room for improvement, there are a lot of tradeoffs involved, and it is not as simple as "don't mix materials with different tensile strengths". If you are interested in more information about the strength of sheathed wood strip construction, please see my pages where I put various layups in an Instron machine: www.guillemot-kayaks.com/Building/Testing/index.html

If it is such a big problem to mix different fibres then why is that the most expensive motorcycle helmets is fabricated with a combination of the three fibres? I need to replace my boats transom and was thinking of using 4 pieces of 9mm marine ply and insert a cloth of kevlar, carbon and fibreglass between them and bond it as a unit to get the best properties of all three in one assembly. But i`m not sure about my plan hence my research on KZfaq before i start using the material. should i just use the fibreglass and go for two 21mm bonded marine ply instead (already got all the materials)

Composite design is not as simple as Mr. Dawes would suggest. There are valid reasons to mix various materials together because each material contributes something different to the final product. You want to be fairly knowledgeable about both the loading and the potential failure modes of what you are building. Since you would be going with a sheathed wood core, the interior and exterior will react in different ways to various loading scenarios. You want to design your layup to account for how your boat will be used.

I would encourage Graham to look at how recurve bow limbs are made. Materials with different properties deliberately combined to create a laminate that is intended to be repeatedly subjected to extreme loads and shocks. It's a whole industry built around mixing materials in a composite lol.

The kevlar is a great fabric when building certain things. Besides the abrasion and puncture qualities its not as rigid as cf.