Skid plate suggestions

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Hulls with shallow or deep V contours are prone to wear down the keel line.

Pete, I’ve seen your boat repair and outfitting work for some years now. Seriously well done boatwork, and I’ve learned a bunch. I’m still learning and hope you will photo document the Mohawk XL 13 and share it here.

I’ve laid full length keel strips on a couple or four Mad River or composite sea kayaks vee bottoms. In that application, if the wear area is narrow enough, Dynel sleeve from Sweet Composites is much easier than cutting a narrow strip of Dynel fabric, and lays down tough as nails two layers at once. That sleeve may have been a Pblanc suggestion, and has proven useful in several applications beyond vee bottoms or skid plates.

Dynel sleeve here (scroll part way down)

https://www.sweetcomposites.com/Polyester.html

The “lightweight” sleeve is 1 ½” wide, the “standard weight” is 1 ¾” wide. The actually fabric “weight” seems the same, or at least I can’t tell the difference. Cutting a 16’ long strip of narrow Dynel from yards off fabric, with edge frays and my kindergarten-wobbly scissor work? Thanks, but no.

Wider Dynel sleeve or, better still, single layer Dynel in wider rolls, something like 3” or 4” wide, would be really useful, were there such a thing. I’m still searching.

With fabric and peel ply already in rolls the rest gets simpler and easier.

Boat taped and papered, bottom coat of epoxy painted on, cut-to-length Dynel sleeve unrolled on the epoxy, epoxy topcoat, let sit a while to fully saturate the fabric, maybe add a little leftover epoxy from the pot where needed, then covered and roller compressed release treated peel ply. Release treated peel ply in rolls!

Bless Glenn MacGrady for finding release treated peel ply in rolls, available in 1” wide to 6” wide. So freaking handy, not just for long narrow strips. A lot of the fabric repairs I do are long narrow cracks or linear slices. Cut me off a piece of that peel ply roll.

https://www.aircraftspruce.com/catal...es/peelply.php

That keel strip may sound like a lot of work, but the sleeve and roll peel is simple as measure to length and make a single cut. Snip, snip, fabric and peel ply both ready to go.

I want the peel ply roll 2” wider than the keel strip epoxy width, so if I get a little catawampus unrolling it over the epoxy it will still cover the area side-to-side. When unrolling a long assed peel ply keel strip it really pays to have a helper standing at one stem, eyeing along the keel line and calling out slight peel ply alignment adjustments as you unroll; it is hard to gauge the center line while standing alongside the hull, and better to keep true along the full length.

Peel ply in rolls is much easier than cutting long thin strips of release treated peel ply. BTW, the white peel ply that looks too much like 4oz glass (mark it as peel ply somehow, it’s hard to tell later) is easier to cut cleanly than the thinner blue stuff.

Whitewater canoes will often wear through at the center before they do at the stems. That is where the hull draws the most water in a highly rockered design, and is also where the paddler's weight is concentrated. That creates a lot of abrasion as the canoe goes over rocky ledges and shelves.

I have needed to install an exterior “football” of fabric on two old WW canoes worn near through at center, a kevlar Starburst freebie (thanks Pete Staehling), and a friend’s WW solo, worn scary thin under the saddle; not a lot of hull flexibility when grinding over rocks with paddler weight on a floor mounted saddle.

Said friend provided the fabric, something then new to me called “Dynel”. I used some thick 6oz S-glass on the first; coulda shoulda woulda used Dynel, but didn’t know there was such a thing as Dynel

Dang, this is making me long for another beater to rebuild.
 
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I do not like the big chunky kevlar and dynel pads at all. They are clunky and can really slow down a fast canoe like a Canadienne or a Sawyer Cruiser. I use fiberglass tape and epoxy. Often a 3 inch roll of tape and then a roll of 2 inch. Then I sand and paint. Works well and maintains the speed and lines of a beautiful canoe.
 
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I do not like the big chunky kevlar and dynel pads at all. They are clunky and can really slow down a fast canoe like a Canadienne or a Sawyer Cruiser. I use fiberglass tape and epoxy. Often a 3 inch roll of tape and then a roll of 2 inch. Then I sand and paint. Works well and maintains the speed and lines of a beautiful canoe.
A skid plate made of 5 ounce/square yard Dynel fabric is not very thick at all, especially if you use peel ply to limit resin uptake by the fibers.

Most fiberglass tapes are made of 6 ounce/square yard fabric although some are as heavy as 10 ounce/square yard. A skid plate made out of two layers of 6 ounce/square yard.fiberglass tape is going to be much thicker than one made of 5 ounce/square yard Dynel.
 
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I do not like the big chunky kevlar and dynel pads at all. They are clunky and can really slow down a fast canoe like a Canadienne or a Sawyer Cruiser. I use fiberglass tape and epoxy. Often a 3 inch roll of tape and then a roll of 2 inch. Then I sand and paint. Works well and maintains the speed and lines of a beautiful canoe.

I agree about big, clunky kevlar felt. But I don’t see a properly installed Dynel slid plate as clunky, or slowing down even a fast, sharp stemmed composite canoe.

Most of the fiberglass tapes I have found have been plain weave E-glass, and there are better materials. Even thick bias woven Twaron.

But Dynel? This is too thick?

PC060024 by Mike McCrea, on Flickr

There are single layer (no pigment or graphite powder) Dynel skid plates on both the stems below, top coated white when I painted the bottom. You would have to get mighty close to tell they were there. Not clunky, not slow, damn near invisible.

P4170001 by Mike McCrea, on Flickr

P4170002 by Mike McCrea, on Flickr

Weeks of experimenting with laying up various fabrics and epoxies showed that Dynel has by far the best abrasion resistance, and if additional impact resistance was desired a second layer of anything – even E-glass – laid underneath made for an abrasion and impact proof skid/bang plate

https://www.canoetripping.net/forums...stance-results

All that experimental work, which continued with Dynel sleeve and various epoxy mixes, and this guy’s simple test was more revealing; Dynel vs 6oz S-glass, abrading the fiberglass and Dynel using the corner of a fire brick (copied from the Glen-L site)


“A 6 pound fire brick held on a 45 degree angle
The test with 6oz fiberglass cloth took 52 strokes to cut through to the wood
The 5.5oz Dynel has more than 250 strokes and is still not through to the wood

Nothing wrong with a multi-layer glass skid plate, especially if one layer is laid on the bias. But it won’t be as abrasion resistant as Dynel. If I am adding “skid” plates I want Dynel, and some graphite powder for a tougher, slippery skid.

I’d like to hear more from Recped; IIRC his canoe had multi layers (like 5 or 6, applied at different times?) of S-glass, wearing through, when he put on a layer of Dynel. I know Recped uses his boats hard, and wonder how his Dynel top layer has fared.
 
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Okay thanks for update on Dynel. Kevlar pads do not get it.

PPine, if you have the opportunity on some canoe in need, give 5oz Dynel fabric, or on a narrow wear area sharp vee stem, Dynel sleeve, a try. A single layer of 5oz Dynel fabric, compressed under peel ply, can be as little as 1/32” think, or 1/16” if you top coat it with a G/flex and graphite powder mix.

On most of the more blunt-stemmed canoes a strip of 3” E-glass tape wouldn’t have come close to covering the worn areas width-wise, so those got a shaped and sized skid plate of Dynel fabric (see photos above).

Cover the epoxied Dynel with release treated peel ply and push down by hand or roller, so the epoxied Dynel doesn’t “swell like an old sweatshirt”. Epoxy/Gflex/graphite powder top coat as you wish.

If you want additional impact resistance on a more WW-ish canoe adding a layer of anything under the Dynel increases the rock slamming performance appreciably, and is still thinner, and far more abrasion-resistant, than two layers of glass tape.

Every boat we own has Dynel skid plates, and I don’t regret installing a single seemingly seamless one.
 
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I attempted to patch that gouge and I'm not sure if I was successful or not. The sides of the tear did not want to lay flat so I don't know if I need to start over or if this will be fine as the skid plate will be going over top of it anyway. I used about a gumball size glob of g/flex and then covered with release tape and used a seem roller to compress. If this looks ok, I think I'll start prepping for the skids tonight
 

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If you don't like the contour of the hull as it is just apply some more thickened G Flex over it and sand it fair and flush when cured. If you are just applying G Flex to fill a crack I really don't see the need to apply release fabric over it. Any epoxy that stands proud of the adjacent hull can just be sanded off when cured. Sort of like overfilling a crack in a wood board with putty then sanding off the excess.

Peel ply is most useful when bonding fabrics. It will limit the resin uptake of Dynel and on any fabric it will result in a smoother edge of a patch. The fibers at the edge of a patch tend to swell up when wetted out resulting in a raised edge. So the peel ply will limit the amount of feathering you need to do at the edge of a patch to get a smooth result. This is especially beneficial when bonding aramid patches since aramid really doesn't like to be sanded much.
 
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Just pulled the peel ply off and I must say I'm pretty happy with the results. I was initially worried I was not going to have enough g/flex to finish the job so I only did one layer of dynel, but I think I still have at least half remaining. For anyone who is nervous about undertaking this project, I'll say as someone who has never done anything like this before that it's honestly not that difficult. The long cure time of the g/flex really eliminates a lot of stress and the dynel cloth is just that, cloth, so it's very easy to handle and cut, even after I drank all the beers I was supposed to be saving for Mike and Pete. Now I just have to do a little cosmetic maintenance and I think the old girl will be ready for the water tomorrow.
 

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Looks good. The peel ply tends to leave a matte texture. If you want a really smooth abrasion plate you may need another application of G Flex. It won't take that much to fill in the texture. Then wet sand with fine paper, say around 600 grit.
 
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