• Happy Winter Solstice! 🌇🌃

Cliff Jacobson: NO to skid plates!

Well, to all my non-binary Demi-paddlers of the single and double type persuasions, there is always this little gem to add to the discussion:
QG5aX2c.jpg

No good on your high tech rubberized bath-tubs, or your scary light composite contributors to global warming, but definitely a touch of class and durability on your wooden and stripper type paddling chariots.
 
Well, to all my non-binary Demi-paddlers of the single and double type persuasions, there is always this little gem to add to the discussion:

No good on your high tech rubberized bath-tubs, or your scary light composite contributors to global warming, but definitely a touch of class and durability on your wooden and stripper type paddling chariots.

and when the brass gets chewed up you can always put a skid plate over it
 
And plus I think kevlar felt is the wrong material for the application in most case!
I tried polar fleece last year for a client and so far so good.... I also did a bunch of skid plates for an outfitter friend of mine out of multiple layers of S glass... seems to old up ok

At least there is a general consensus that kevlar felt is a poor choice in material for skid plates. My guess is that it was (still is) included in skid plate kits because it doesn’t fray at the edges during application and kinda sorta conforms to simple curves, so even folks who have never done and epoxy and cloth work could install a skid plate of rudimentary sorts.

Why some manufacturers continue to offer kevlar felt skid plates as a ($100) factory installed option is a mystery. Ugly factory installed kevlar felt skid plates, not even pigmented. Come on guys, y’all know how to work with cloth and epoxy. Why still kevlar felt?

It's true that Kevlar fuzzed when sanded, but I discovered by experiment (wanting to smooth that fresh plate) that it can be milled down with a farrier's file, without leaving any fuzz. Be very careful around the edges!

It seems to me that it's the epoxy in the matrix that provides the abrasion resistance, more than the fabric.

In some kevlar felt skid plate kits I believe that the epoxy does add substantially to the abrasion resistance. Some skid plate kits; once upon a time most skid plate kits came with uber-stanky thick viscous urethane resin, which was tough stuff and probably shown to cause cancer in California. Today most kits (@ $100) come with what seems to be regular epoxy resin. Except for Old Town’s skid plate kits. See Goonstroke’s comment and link, and the $300 MSRP.

On DIY’ed Dynel skid plates I have been using a 50/50 mix of regular epoxy (West 105/206) and 650 G/flex. In odor and viscosity G/flex seems a lot like OT’s urethane resin, and on vinyl skinned Royalex using some sticks-to-anything G/flex in the mix can only help. On a poly hull I would use straight G/flex, and flame treat the surface first.

As in Steve’s technique I filed down the abrupt edge of a poorly installed felt skid plate on a friend’s Appalachian. An extraordinarily tall, abrupt and gurgly edge; he had used every ounce of skid plate epoxy in the kit, every kit I ever used (regret every one) came with way more epoxy than needed, and he continued to lay it on as it began to thicken in the pot.

P5260024 by Mike McCrea, on Flickr

A better solution - not that anyone should ever install a kevlar felt skid plate - is to wait until the epoxy has begun to set up and then use a tongue depressor to push down along the tall standing edges of the felt. The epoxy saturated felt will bevel down along the edges and hold that compressed shape. With the edges faired down it won’t gurgle as badly, and will be less likely to catch an abrupt skid plate edge on a rock and bust off chunks.

About skid plate material compression, any material will lie smoother and more flush if compressed under release treated peel ply. Someone on this board once remarked that Dynel “Swells like an old sweatshirt” with epoxy application. It does, but compressed under peel ply, by hand or hard roller, it practically vanishes in thickness and is still as abrasion resistant. Even multi-layer skid plates dang near disappear when peel ply hard roller compressed as the epoxy sets up.

I don’t know if peel ply compression works with polyester sweatshirt material or Polar Fleece, but photos of similar uncompressed materials lead me to believe that peel ply application would be a good idea on those thick swelled materials as well.

It doesn't take long to sand away epoxy. It takes very little extra time to sand away epoxy+carbon. It takes longer to sand away epoxy+E-glass. It takes longer than that to sand away epoxy+S-glass. I'm not quite sure how long it takes to sand away epoxy+dynel because I've always given up before I got that far.

Alan, yup. Exactly as demonstrated in the experimental skid plate materials impact and abrasion tests. And as demonstrated in the real world on three sea kayak that are client-used/abused in the most abrasive environment, Everglades trips involving limestone, worm rock and oyster bars. One kayak done with E-glass, one with S-glass, one with Dynel.

The E-glass and S-glass didn’t last a single season, the Dynel kept on going.

What is most interesting to me is that some paddlers, who I believe actually use their boats a lot, do not need skid plates for decades, and other’s need a skid plate within a year or two. Or, like Alan, in three weeks time.

I don’t think it is necessarily bad boating habits; different trips and locales and environments play a part. A couple of our decked canoes are used almost entirely on shallow sand-bottomed bays. So shallow that grounding out the boat in 3” of water passing over an extensive sandbar is pushing/wading/dragging routine. No limestone, no worm rock and dang few shells, mostly just coarse sand. Even that minor but frequent abrasion wore away at the stems.

Another reason to wait to see where the abrasion wear areas occur; our more blunt stemmed Royalex canoe showed abrasion wear over a wider but sometimes shorter area. Those skid plates were installed, an inch or two beyond the demonstrated high wear areas, as need. Some on blunt stemmed RX hulls were short and fat.

PB180020 by Mike McCrea, on Flickr

And some were longer and skinnier

PB180015 by Mike McCrea, on Flickr

Canoes have different stem shapes, and one size does not fit all.

Our sharp vee stemmed decked canoes that suffer coarse sand abraded stems needed only a couple inch wide strip, but three feet long.

PB180018 by Mike McCrea, on Flickr

Gawd bless Dynel sleeve for that application. Several of the aforementioned client abused sea kayaks have full length vee bottoms. Extremely worn vee bottoms, they will soon be getting a full keel length run of Dynel sleeve, compressed under peel ply. Still wish I could find peel ply tape; rolls of pre-cut 3 or 4 inch wide peel ply.

Yeah, yeah, too many dang words. I estimate I have installed 50 or 60 skid plates, including (I regret every one) kevlar felt, E-glass, multi-layer S-glass, thick kevlar tape, thick bias woven Twaron tape, Dynel fabric and Dynel sleeve. I believe in the value of a proper size/shape/material skid plate, and remain fascinated by best-practice skid plate application.

The best, or at least funnest, of the kevlar felt skid plates came at the end of (for me) that era. We put skid plate kits on two canoes owned by a pair of paddling sisters, Patty and Theresa, aka (self named) “The Squatters”. They bought two OT skid plate kits and brought their boats up to the shop. They were most delightful shop partners, and quick to pick up “Watch me do one, help with one, do the rest on your own while I watch” shop practices.

As we were finishing up in the shop Patty mentioned how she “Likes bright shiny things”. I handed her a vial of gold glitter and she sprinkled it over the still wet epoxy on both her and her sister’s canoes.

Their concocted story, if anyone noticed their flashy skid plates, was to exclaim surprise and mention, in an offhand way, that they had recently been paddling Yukon rivers that ran through old gold mine claims.
 
The tree hugging illusion aside I'd say the brass stem band looks much more alluring than those black skid marks on the plastic boat underpants. lol
 
I've installed my share of skid plates over the years. After sanding, applying a small amount of epoxy with a flexible blade hardens up that fuzzy felt into a nice smooth, dimpled, hard surface. I wait until the epoxy gets tacky and smooth it out. I ran over a rock the other day with the wind at my back, boat loaded and trimmed - stupid muddy water and my bad memory. Anyway, I got a few long gouges down the hull, one right down the stem. Gonna fill em soon as I finish another project. The skid plate I installed had a barely noticeable scratch that mostly wiped off. The Kevlar was gouged along that same line. I'm also refinishing another boat I carried across the WCPP. Wind caught it and blew it across the rocks when I forgot to tie it down. Lots of scratches and a few deeper gouges. Internal factory skids protected got a couple small chips that I sanded off and filled, nowhere near as serious. I believe in Kevlar skid plates, even on Royalex they've proven durable if installed properly. I sanded on the gouges below, preparing to fill. I've not had too much damage to repair over the years so I'm kinda glad I hit that rock during the quarantine.

I use generic resin and a MEKP hardener with good luck, although Northwest has a 1:1 mix that seems good too.
 

Attachments

  • 07B5D989-5699-4838-B80A-038294F85296.jpeg
    07B5D989-5699-4838-B80A-038294F85296.jpeg
    377.3 KB · Views: 4
  • 9BD91F6F-6730-4B5C-85EA-56D95E5D8A9F.jpeg
    9BD91F6F-6730-4B5C-85EA-56D95E5D8A9F.jpeg
    500.5 KB · Views: 4
  • 268F62AC-B498-4767-9EEE-12EB6CD88553.jpeg
    268F62AC-B498-4767-9EEE-12EB6CD88553.jpeg
    519.9 KB · Views: 4
Last edited:
The tree hugging illusion aside I'd say the brass stem band looks much more alluring than those black skid marks on the plastic boat underpants. lol

That brass stem band is far more elegant on a stripper than the black skid plates on my Royalex canoes. I could probably add something similar to the blunt stemmed RX hulls, maybe a curved piece of chrome bumper from a ’56 Chevy Bel Air.

Those black skid plates on my boats don’t bother me. The canoes all have black gunwales, deck plates and seat webbing, and the decked boats have black seam trim, carry handles and etc, so my panty stains are color coordinated ;-)

PB180013 by Mike McCrea, on Flickr

Those Dynel skid plates are black for a couple reasons. Dynel wets out kind of milky white, so some pigment in the epoxy mix helps. I could have pigmented the skid plate epoxy red or green to match the RX hull color, and have used white pigment on white bottomed boats; those white on white skid plates are essentially invisible.

Black works for me because I add graphite powder to the epoxy mix. Adding graphite powder to the epoxy mix produces (per West System) “a low-friction coating with increased scuff resistance and durability”. Kind of like Alan adding Dynel skid plates when he builds a canoe, adding a spoonful of graphite powder to the epoxy mix only takes a second and provides beneficial protection.

When the boat is in the water not much of those black skid plates is visible anyway, and no one I paddle with seems to have their knickers in a bunch about it.
 
I use a couple of pieces of fiberglass tape and epoxy and try to stay out of rock gardens at low flows.
It is good to see so many boats getting used.
 
No added weight in the stems there.

I love the four flat head screws on each piece holding them in place.

Pretty work, better than using an ester resin and neglecting to add the MEKP catalyst ;-)
 
As we were finishing up in the shop Patty mentioned how she “Likes bright shiny things”. I handed her a vial of gold glitter and she sprinkled it over the still wet epoxy on both her and her sister’s canoes.

Their concocted story, if anyone noticed their flashy skid plates, was to exclaim surprise and mention, in an offhand way, that they had recently been paddling Yukon rivers that ran through old gold mine claims.

Mike, I am so going to use that on my next skid plates! The glitter will be pretty obvious, on the black background.

So...maybe my thoughts on epoxy abrasion resistance are based on the fact that I've been adding graphite too. Y'all convinced me on dynel though. Yeah....basic black goes with everything, but add a little gold glitter for class!
 
Down to bare wood after 3 weeks:
20150905_001 by Alan, on Flickr

Didn't wear through the dynel after 6 weeks:
20161017_002 by Alan, on Flickr

20161017_001 by Alan, on Flickr

Alan, I recall that the black hull was the one you used on one of your marathon (Bloodvein?) trips. Those pictures show more hull scratches and end damage than I have accumuated on any of my 15 canoes/kayaks, including all my 30-40 year old whitewater hulls. Was there actually any WATER in the places you were paddling?

I put the later-to-be-discovered-unnecessary Kevlar felt skid plates on my first canoe, a yellow Royalex Mad River Explorer. Never again, on any of the next 14 boats, for the reasons stated by Jacobson and me. However, I cannot believe that a couple layers of ugly black Dynel are more effective against abrasion or collisions than ugly yellow Kevlar felt. The felt at least has the virtue of doing the job, if the job needs doing. I'm with those who say that a properly designed, properly manufactured, properly paddled and properly treated canoe will not suffer end damage under normal conditions. There has never been any significant abrasion on the skid plates of that 40 year old Explorer. One of them is curling and peeling off, however.

If end damage does happen for whatever reason, then of course it makes sense to repair it after the fact. That's not Jacobson's issue and has never been mine.

I can see logic in preemptively beefing up the ends (and all other parts) of a composite hull that will be used on long river trips in true wilderness. Some composite canoes like my SRT have internal skid plates, whatever that's supposed to mean. I have no idea why that's any different than extra layers of fabric in the ends. And, in any event, something internal isn't going to stop abrasion of the gel coat and outer fabric layers if the canoe is so abused. If I hadn't bought the SRT used, I'd never order a new one with internal skid plates. The canoe is already too heavy.

As to Chip's question about wear underneath a whitewater saddle or pedestal, it's been my experience that the method of attaching saddle or pedestal affects the hull abrasion under it. Saddles that are secured under two thwarts, one at each end, such as early long foam saddles and the Perception saddle, make the bottom more rigid and less flexible, thereby promoting more hull abrasion under the saddle. Saddles and pedestals that are glued or strapped to the bottom of the hull without any thwart support allow the hull to flex more and result in less abrasion under the hull. However, there is a downside: The free-standing saddles are more likely to result in oil canning and perhaps more permanent flex damage to the Royalex in the middle of the hull.

Overall and to be Freudian, methinks many skid plates are the product of the irresistible compulsion, common to addicts of any hobby, to buy gear and gadgets, add widgets, and tinker with their toys. Cripes, I bought a $300, 300 pound, custom made spray cover for that Explorer. And three double paddles. And and outboard motor. And made a rowing rig. Installing skid plates was the least of my frivolous and expensive behaviors with ultimately useless canoe doodads. (Actually, I like to row and miss that rig, which is somewhere in my cathedral of entropy.)
 
Mike, I am so going to use that on my next skid plates! The glitter will be pretty obvious, on the black background.

So...maybe my thoughts on epoxy abrasion resistance are based on the fact that I've been adding graphite too. Y'all convinced me on dynel though. Yeah....basic black goes with everything, but add a little gold glitter for class!

Steve, little black panties with glitter always get my heart racing, even when I’m on the river and not at Café Risque (I-75, exit 374 south of Micanopy FL)

When we had the Squatter’s OT Pack, Wenonah Sandpiper and OT Camper in the shop for (regrettably) kev felt skid plate installation we also had my skid plate-less Mohawk Odyssey awaiting the dregs of the kit resin. We were using up every (too many) ounces of the OT skid plate kit urethane resin, and had some leftover shop stock kevlar felt, so we tackled four boats at once.

Patty mostly ran out of gold glitter by the time she got around to sprinkling it on my Odyssey, but the few flakes she had left were still eye catching on that skid plate, even after it had worn down years later.

Yes, Dynel cloth. Or, if you need a long skinny 1” wide skid plate or vee bottom keel strip, Dynel sleeve (Sweet Composites). Not open mesh woven Dominatrix-stocking Xynole, which does afford similar abrasion resistance, but doesn’t cut to shape without frayed edges very well. 5oz Dynel holds a cut edge, even when wetting it out.

https://www.jamestowndistributors.com/userportal/show_product.do?pid=4214

You definitely need to compress Dynel under peel ply, it swells like crazy otherwise, and sets up 60-grit epidermis-scraping rough without peel ply. But once you go Dynel you’ll never go back, the abrasion resistance is incredible.

A single layer of Dynel seems to resist most impacts.

I too use a thin layer of Dynel which is treated with G-Flex and West System resin, barely visible when treated with Peel Ply. A Dynel SP weighs next to nothing
And yes I trip, I do WW, I have bounced of rocks at a furious pace and ground out on sand more times than I can count and any boat with the Dynel on it has shown next to zero wear and tear.

My experience has been much the same. That said, after cogitating on the results of the skid plate impact and abrasion experiment, I’ll add an under-layer of something bias cut, fiberglass or Twaron tape or etc, epoxied below an overlapping outer layer of abrasion resistant Dynel from now on.

http://www.canoetripping.net/forums...late-test-materials-impact-resistance-results

With the materials and peel ply cut to fit adding a bias “impact layer” under the Dynel doesn’t take much extra time and, if you use a hard roller atop the peel ply as the epoxy sets up, multi-layer skid plates are not much thicker than a single 1/16” thick layer of Dynel.

Even 8.5 oz, 16 ml thick bias woven Twaron tape (Sweet Composites) essentially vanished bumpless under a Dynel top cover when hard roller compressed as the epoxy set up under peel ply.

Anything underneath, even plain woven E-glass tape, is better than nothing. Once the hours of sanding and cleaning, taping and papering prep work are done, I want two layers laid down for my finished efforts; one for abrasion, one for impact. It is worth spending the extra minutes required to lay down multiple layers.

And yes, add some black Graphite powder in the epoxy mix. I add a little dab of black pigment as well, to make certain than the fabric is colored through and through; even fine grained Graphite powder seems to rest mostly atop the fabric without penetrating, the color agent pigment completely saturates the cloth.
 
Alan, I recall that the black hull was the one you used on one of your marathon (Bloodvein?) trips. Those pictures show more hull scratches and end damage than I have accumuated on any of my 15 canoes/kayaks, including all my 30-40 year old whitewater hulls. Was there actually any WATER in the places you were paddling?

The white hull was from the Bloodvein trip. The black hull was the following year, a 6 week nearly 600 mile trip starting and returning to Wollaston Lake. Most of the scratches on the black hull are superficial and wouldn't be so visible on a lighter colored hull. Only a couple actually got to the cloth. These were not highly rockered boats so if I found a rock, which happened regularly, the stems usually took the first hit. The rocks, especially on the Bloodvein, seemed particularly abrasive and jagged. Much of the damage occurred paddling upstream when I'd tuck in close to shore or close to rocks trying to avoid current. Sometimes the current would push the bow into those rocks at fairly high speed when I wasn't expecting it. There were also a lot of poor landings where I chose to abuse the boat by dragging it up or over rocks rather than risking walking over those rocks with the canoe on my head. I had enough close calls with falls on slippery boulders without carrying anything.

I've paddled thousands more miles locally and on less strenuous trips and my hulls never looked anything close to what those two did so I do know how to treat a boat properly. I've also found that since I started building canoes I'm more likely to be hard on them. Either because I have confidence in how they were made or because I know that it will be a simple job to repair any damage.

Alan
 
Back
Top