Clear keel strips?

Was searching around in older posts, which lead me to find online.

They claim to have a clear smooth formula of this stuff available now, and for sale by the quart. Has anyone ever applied anything similar to their boats themselves, and how involved would it be? Is it no more complex than clean, tape, and apply with a roller, or should I leave this to the experts?

I’m afraid I might get carried away with the stuff, and apply it to the whole hull. Am also tempted to go with a nutty color scheme for the bottom of my boat…

Non slip.
perhaps not the best thing underneath your boat.

Now the Kevlar under mine is rather rough so it may be fine.

Looks like another paint though.

I’m wondering about this stuff:

There was a thread awhile back but I can’t find it. Anyone used a paint-on truck bed liner for a keel strip material?

not just put a real keel strip on?

it’s not that hard…and if it’s worth doing, it’s worth doing right.

Best Wishes


Keel Strips

– Last Updated: Jan-23-08 1:51 PM EST –

Seakak, I found a thread somewhere (on a monster truck forum) that compared the herculiner to the Durabak, the main difference is supposedly the Durabak is more UV resistant, and smoother. The Durabak is available in a smooth formula, with no rubber granules in it, while the herculiner has the rubber granules in it. Seems like a smoother formula would be better.

I would also like to get some info from people who have done this, and see if it has any advantages over a conventional keel strip? Lighter, more protective, easier to apply?

look at where the wear is first
if it’s primarily a few square inches in the bow and stern it doesn’t make much sense to look a material suited for square feet of application.

Just a heavy paint
According to the maker, the recommended two coats of Durabak will leave a protective covering of only 25 mil in thickness, or 0.025 inch.

By contrast, a good DIY keelstrip of conventional resin and fiberglass cloth is considerably thicker, perhaps by as much as four or five times. I presume this would provide more durable and strong protection from impacts, etc., than the paint-like coating of the Durabak.

DIY keelstrip:

a friend applied an ablative layer using resin thickened with glass beads on the ends. I’d think a putty made of epoxy/fumed silica would applied to a 3/4"x8" strip at the ends would be sufficient for high wear. Applying something all the way along the keeline doesn’t make much sense because the wear spreads out towards the middle of the kayak. It would make more sense for the manufacturer to simply make the gel coat thicker there,and heavy, or add a layer of s-glass in the ‘football’ area below the waterline where it would add actuall durability for abrasion AND impacts.

maybe nigel could do it for me

Durabak here
Keel strips don’t really cover much. I use Durabak on the entire bottom of the hull. Pros: This is a very durable material (for truck bed). No abrasion can touch the epoxy layer, let alone the Kevlar or fiberglass layer. Cons: You will not be able to glide your boat over a rack, such as Thule’s Hydroglide. In addition, this is not a self leveling paint. Brush works better than roller. The remedy to the nonskid problem is to apply a coat of glossy marine paint over Durabak. If you want to use Durabak, I suggest that you cover your hull with Scotch 375 clear packaging tape and apply Durabak over the tape. You will end up with a truly sacrificial layer. If you don’t like it, you can always peel everything off.

that’s the thickness of four heavyweight garbage bags. I’d rather have a layer of 4oz s-glass under the gel coat and not bother trying to protect soft sacrificial gel coat.

That’s what I use
Plain old epoxy and fumed silica. Lasts a good long time, and is easily sanded and re-applied when needed. I only use it where I need it, which is along the keel from the skeg box rearward.

This spring I’ll be putting some on the keel up towards the bow. The gelcoat there is starting to get thin.

Keel Guard
Try looking at Megaware Keel Guard made by 3M. It is made for boats and PWC’s but you can get a kit and cut it down to the size you want, and sand the edges to suit. It’s a heavy duty rubber like you would see on some car doors and works great.

what’s “right”?
That sounds like doctrine to me. If something works as an alternative, why is that not also right?

Durabak on the keel

– Last Updated: Jan-28-08 11:47 AM EST –

I can speak directly to your question, as I applied Durabak as a keel strip on my Nova Craft Bob Special late last summer. It is not a quick process, but you can certainly do it yourself.

First, about my boat and why I felt I needed to do what I did. My Bob is a pre-production prototype, one of the first of their Blue Steel hulls. Like all composite Bobs (until the last couple of years), it was produced with a “shoe keel,” about 3”-4” wide, 3/4 inch deep and covering the center 80% of the hull. This keel was put there for stiffness, but was eventually found to be unnecessary. The boat is now produced without it, though the shoe keel is available on special order.

This being a boat meant to test the strength and durability of Blue Steel, it was really put through its paces. It did lots of class 3 work and time up in the Shield. It was “Rode Hard and Put Away Wet” and used by many different paddlers. As we’ve learned since those early days, it is easy to scratch up Blue Steel, but very, very difficult to actually damage it. The one place where my boat did show real wear was right along the edges of the shoe keel, where repeated rock strikes cracked the clear gel-coat and eventually broke it up, delaminating small sections. The Blue Steel fabric itself was never broached (not even worn), but it didn’t look good on what is, to my eye, an otherwise beautiful boat.

I spent about a year looking at the options and eventually decided to try a coating. I tried out a Mad River Explorer 16 that had used the Herculon (Herculiner) treatment over Royalex and found (to no great surprise) that the non-skid nature of the product made it useless over rocks. Remember how those old Grummans would come to a halt against a rock? This was worse!

Eventually, I found Durabak, which, as pointed out in an earlier post, comes in a smooth version and in a wide variety of colors (not all of them are available in the smooth formula.) It is made by Cote-L Industries ( and they are a real industrial solvents and coatings company, not a spray-on bedliner company. This means they have real engineers there to talk to. However, it also means that you talk to real engineers, who pretty much expect you to be a real engineer, too! Eventually I found someone who had experience with using Durabak around water. It was a little like what having a conversation with Fat Elmo must be like, “Vee haf Durabak on dere docks in Gdansk for seven-eight years, no problems!”

They did tell me (both from the engineer and in their on-line instructions on using this product on fiberglass) that you should absolutely use a primer, which pretty much negates your idea of using their clear formula. I chose a dark gray to use on the Blue Steel, having seen this color combination on a Nova Craft PAL at Canoecopia; the combination looks great.

I ordered the Durabak, and “accelerator” and their MetCote primer and started the prep work, including fiberglass patches, faired-in, over the worst of the damage. Like most projects of this type, prep is critical. I taped it up so that the Bob would have combination skid plates and keel plate, bow to stern. The gel-coat was sanded down with 40/60 grit paper and cleaned with xylene. The UPS guy arrived, I opened the box, took out the primer, and read that it was, “Not to be used in or near water.” Hmmmm. Another engineer at Durabak questioned the parentage of the first and then told me to get “any epoxy primer that is compatible with moisture cured polyurethanes (which is what Durabak is).” And did they sell such an animal? No! And did he have any suggestions as to where one would get such an item? Sure, he said. “Any place that specializes in those types of applications.” I began calling paint stores and, after ½ a dozen calls, was pointed toward Body Shop Supply Company, where they knew exactly what I needed. It is called Omni MP-170 epoxy primer and hardener. It worked great.

The Durabak can be brushed (as pointed out in a post above) but is much easier applied using a 3/16” nap mohair varnish roller (hard to find, but can be ordered from West Marine.) I applied mine on the hottest, most humid day of 2007, and the drying time suffered. I’m not actually sure that it was completely dry until two weeks later. It uses an accelerator and starts bubbling up as soon as that is mixed in. You cannot plan on saving any left over; when you are done, so is the product!

This stuff is very tough, certainly way more than the “two coats of heavy paint” theorized in an earlier post. It won’t be clear just how good it is until the end of this (or maybe the next) season. After ½ a dozen times out, I think it is great. You do lose some slickness over rocks, and you can’t take it out before you are absolutely sure the curing is finished (I have a little sand embedded in one spot because I was in too much of a hurry.)

I hope this helps. It is NOT a quick and easy fix, but it may be a really good (and, to my eye, good-looking) fix. It takes time and attention to detail, but I’m happy so far.

Good info
Thanks mckennaroad

You are most welcome. I know the person who did the keel strip in the article posted by Delphinius (he’s one of the experienced paddlers/craftsmen at Rutabaga); his work came out beautifully and would certainly be something to consider copying. I might be tempted to replace the gelcoat step with one of the Durabak colors and perhaps end up with the best of both worlds.

Now my canoe

I would have used clear Durabak if I knew.

Thanks again
both of you guys…