I recently bought a home-built kevlar canoe.
The builder did a few things in less-conventional ways, but I am confident in the hull nevertheless.
He didn’t put on the ugly kevlar felt skid plates to the outside of the stems,but he did put them in on the inside.
This seemed like a great idea, much like a kayak end-pour. It doesn’t rob efficiency, but strengthens the stem.
Any thoughts?
If they’re on the inside
I wouldn’t want to think of them as skid plates. As for the compressive strength of kevlar felt … I would think extra cloth on the inside would be a better choice.
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– Last Updated: Apr-19-10 11:29 AM EST –
Bell tried integral Kevlar felt skid plates in the mid 90's but whether we wet then out with the hull or let them set up prior and installed the solid parts when laying the hull up, we got outgas bubbles along the edges.
Vacuum Infusion would have eliminated those bubbles.
We always intended to do integral Kev pads in Placid boats, but the cosmetics with the tan waterline patch never looked right. So, we threw 11 layers of fabric, 3 carbon, 8 Kevlar into the stems. No problems, ever.
External skid plates create turbulence which increases hull drag and slows progress trhough the water. They also deepen the stems in the water, compromising handling. That is two wrongs; external plates are contra-indicated until the hull is wearing through. Then put 'em on, sell the boat to a fisherman and get a new canoe!
Truin
Yeah, I’d rather not have a "skid plate"
internal insert. Seems like it couldn’t be as strong as just using a rational sequence of cloth layers like you describe, CE.
Bell’s doing it now
Internal is the key word. In today’s Bell boats, there is a single layer of cloth laid down covering the outside of the hull, then the felt skid plate, then the rest of the boat.
With ultralight boats, the problem I see is wearing through the stems of the boat from abrasion. In Bell’s method, on layer, the layer that keeps a clean hull appearance is the only layer affected prior to wear taken to the felt.
Wenonah will build a boat by putting skid plates in the mold first, then building the boat. Many outfitters choose this option for their ultra light boats. There are some issues with bubbles around the edge of the skid plate as the cloth can’t make the transition from behind the felt to flush with the hull quite smoothly. But for an outfitter boat that’s going to be used, not important.
What is less known is that Wenonah has a similar method that is quite popular in Europe. Again, the skid plate is put in the mold first, but then they spray gel coat, followed by the cloth. The gel coat creates a clean perimeter around the skid plate and cloth is hidden. Europe likes flashy, and exposed skid plates are definitely different. I’m also told that lime green, yellow, and orange are popular canoe colors in Europe.
If your builder created the boat, then used the felt skid plates as the final layer on the inside, I don’t see any advantage other than a slight increase in stiffness but at the cost of significant weight increase. To utilize the durability of the felt, you would have to abrade through every layer of the hull. Surely the rest of the hull would have significant wear also at this point.
There will never be a good reason to
use Kevlar felt for a built-in skid plate. It is a structurally inferior material. The only reason to use Kevlar felt outside is that Kevlar felt sticks together, sops up resin, and can be applied by almost any dufus.
Two S-glass outer layers stiffen a boat and provide a hard, smooth wearing, surface.
If Bell or anyone else are using Kevlar felt for inside skid plates, they must be doing it for the sole purpose of advertisiing to customers. They might as well use interior layers of S-glass.
a test then
We’ll take two layers of S-Glass and a standard thickness of Kevlar felt and put them to the test. 1st one to be removed by a belt sander looses. Right there’s the reason for Kevlar felt. It’s not structural, it’s abrasive resistant.
Where in Europe?
not in the Netherlands and Germany afaik
What is less known is that Wenonah has a similar method that is quite
popular in Europe. […] Europe likes flashy, and exposed skid plates
are definitely different. I’m also told that lime green, yellow, and
orange are popular canoe colors in Europe.
Internal skid plate
is an oxymoron.
Keep the Open Side Up!
Pagayeur
Who you callin’ an oxymoron?
Good points.
Seems, though, that the stiffness would be good in preventing the hull from deforming in a rock collision.
I expect that extra thickness and strength would be much better than not having it, should a sharp rock ledge be the nature of the impact.
Agreed, though, that there are likely better ways.