Foam blocks on a roof rack?

Hey there, first time posting, and it is a bit of a silly question about canoe transportation.

My partner and I have been paddling recreationally (in kayaks) for a few years now and in the last year have gotten much more into canoeing - getting a dog started us down the canoe road and we’re loving it!

We have an 18 Subaru Outback with roof racks and recently added 2x4 wide racks so we can double carry. Now my question is, does anybody use foam blocks in addition to their rack system? I personally think it’s not necessary and we argue about it every time he demands we put the foam blocks on.

I’d love to hear what other folks do! I know foam blocks are great if you don’t have a rack, but I don’t see anyone else putting foam between the boat and the rack.

Thanks for your input!

Not clear

What is holding the weight of the canoe, the rack or the blocks on the roof of the car?

Are the blocks resting on the car roof or the rack?

What purpose are blocks serving?

Foam blocks on the rack will cushion the boat and reduce vibration but add height to loading and unloading.

I have used blocks on roof to carry the weight of boat and tied the boat to the rack for secure travel!

I have sometimes used foam blocks between the gunwales of a canoe and my rack crossbars.

Oiled gunwales on wood gunwaled canoes are often stained by the vinyl covering rack crossbars. A foam block or piece of pipe insulation placed between the gunwales and rack protects the gunwales.

Another reason to use foam blocks is that some highly-rockered canoes will hit the cab of a truck rack or a rack mounted on a truck cap and a foam block is necessary as a spacer to prevent this.

The foam reduces marks and scuffs, reduces sliding, and adds some compression. I dont think its an issue of safe/unsafe.

Cam straps should enable secure tie down without foam. What are you using, rope, ratchet strap, cam strap, etc

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I’d say the foam doesn’t do any harm and may add the advantages that rnsparky listed. So, in the interest of partnerly harmony, if partner likes to use the foam blocks why fight it?

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Yes, I use foam blocks between the gunwale and the crossbars with my wood gunwale canoes, firmly strapped down with cam webbing. Aluminum gunewale canoes are placed directly on the crossbars, but I also use gunwale stops that clamp to the crossbar, preventing side shifting of the canoe.

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This wood rack has removable hull profiles for the kayaks, with screwed and glued stop blocks at the ends of the “bars” that keep plywood sheet from sliding around (a C clamp works too). The end blocks are also tie down points for when we carry the canoe; consider adding them to yours. An eye bolt at the same location would also keep the boat from sliding sideways.

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Bungees are not good tie downs for a couple of reasons. They can stretch and fail in crosswinds and they can hurt you if they pop loose. A friend and his wife were replacing one that came loose on a trip. Her end was not secure when he pulled his end and the hook cut a gouge in his face.
Of course it was dark in the middle of nowhere Florida.
Use NRS straps or an equivalent.


No, it is not inherently unsafe to load boats directly onto the rack without foam between the boat and the rack.

I mentioned a couple of reasons why it might be advisable to do so.

I don’t use foam on gunwales. Mine are metal, if they were nicer I likely would.
I also don’t have the stoppers to avoid slide to side sliding. Might be worth tossing that in as an idea to add to the 2x4s.

However I DO add something that I haven’t see any one else do. I line up the one of the thwarts, front, over a cross bar and strap the thwart to the cross bar.
I happen to use a long enough strap to then run out back and daisy chain the end to use as my tail or flag.

I also put a knot in the middle of the bow line and run it to both sides of the car, so it is triangulated. But I honestly think strapping the thwart to the cross bar is the part that does most to reduce movement.

I use foam blocks on all my canoe gunnels.

Foam blocks or even split closed cell foam pipe insulation will help protect the gunnels and rack from scratches, but are not essential. They might also prevent any shifting from side to side. However, with cam straps the shape of the boat is enough to keep it safely secure. Cam straps don’t stretch and even with carrying several hundreds of pounds of 21’ two inch diameter steel pipe I’ve never had them fail.

Still, just for protection I’d always use some sort of padding.

Nope - goes right on the rack. I have a Thule square bar. If I was going to use something I’d probably use the gunnel blocks designed exclusively for canoes, but I don’t find them necessary.

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I use pieces of clear flexible plumbing tubing to protect the gunwales and to add friction; they definitely help the boat stick in place. I agree with others that they probably aren’t essential for safety if your bow and stern tie-downs are attached properly but if you are putting a boat on 2x4’s with no load stops it’s going to wiggle in the wind at highway speeds. I like the boat to be rock steady for peace of mind so I use padding even with load stops.

Here is my 2 cents on the subject and my logic runs a little contrary to some of my friends here and I’m more in agreement with your no foam approach. I also use attached 2x4s to widen the platform for two canoes and use cam straps for tie down and also for bow and stern safety straps. I see this as wearing two belts and two suspenders to keep your pants up or in this case keep the boat with the car in the case of something really going wrong.

Foam will protect the boats gunwales if that is an item of concern for you. In my case with plastic gunwales against wood I have no concern about that.

Cam straps do stretch albeit a small amount as does the hull of the boat and that stretch and deflection is what holds the boat tight. The straps are designed to work that way with the materials used. They are a good match with the strength of the hull for accepting the force as well as the 2x4 being slightly compressed. Foam introduces a new variable and when placing foam in there the max holding force is a function of the type foam you use and how far you compress it and it for the most part negates the way the straps were designed to stretch and hold. To get to the full tension of the straps without the foam say a pool noodle you would likely really be squeezing the noodle down to nothing.

The thing I don’t like about foam is I don’t know how it will react over time. If it rains will it produce less force or if it warms up during the day. I know straps can do the same thing but IMO it is less and is a factored in amount that is more constant.

If the foam is intended to cushion the load like a spring and the canoe weight is say 50# then pulling down on the canoe would make the straps go slack.

Side block I thought about adding to my 2x4s and they would be a good thing, but I didn’t add them as they hinder sliding the boat across the 2x4s and once strapped down using the over and under method with two strong people pushing and pulling on the canoe it is clear the whole car is rocking and the canoe is not moving.

So put me down as no foam, but if you want foam find something really thin and really hard to compress like a strip cut from an inner tube.

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I use gunnel blocks.

Thinking about my above post over breakfast I would like to add something to settle the dispute one way or the other for you.

The solution is to mount the canoe with and without foam blocks and after it is strapped down grab the gunwale and push and pull the boat as hard as you can and look for boat movement relative to the car. When I strap mine without any foam the canoe feels like it was solidly part of the car if I move the canoe an inch the car moves an inch. I haven’t tried it with foam so I can’t say how that will feel but I have a suspicion it will feel different.

One tip on the straps and getting them tight is to position them so you are pulling down rather than up. Much easier to put a constant force on them. Another trick I learned here is I open the back doors and put the extra strap over the door and slam it shut to get the tails under control.

With foam blocks it doesn’t budge either with the cam straps tight.

I also use bow and stern lines tied to the four corners of the car. Coming back from WW canoeing the Natahala River I had the stern and bow tied in this fashion with the foam blocks attached to the gunnels of the canoe and the face of the block compressed by just the ropes down onto the round Yakima cross bars. I was called away to photograph a couple we paddled with run the falls at the takeout. Coming back to the car I got in and drove away over winding mountain roads up and over the high pass (5,000 feet) near Wayah Bald and back down to Franklin then all the way back home in Central SC. It is about a 6-hour trip. The next morning, I realized I had not put the cam straps on. The boat was rock solid without them. The ropes a resulting compression and friction of the foam held the canoe in place.

No, I haven’t use that as an excuse to forgo the cam straps. I like a belts and suspender approach so use straps, four corner rope tie downs, and foam blocks. This in no way implies others need to do the same.

So are you using foam blocks made for snapping over the gunwales of the canoe?

I see people talking about pool noodles with a slit cut in them and pipe insulating foam tube. There are a million types of foam some open and some close celled. The density of close cell foam is a pound per cubic foot number and rubber like products give a durometer shore rating scale. I really don’t know enough about the friction and force to tell if one setup is better than another. So doing a side by side comparison of whatever foam you want to use is likely the best way to tell if it is helping, harming or doing nothing.

I just see it as another step in the process.

They are dense closed cell foam blocks that sort of snap over the gunnels. Quality stuff. However, what is best are the ladder or canoe brackets. I have two pair on a set of bars I use on my car rack for carrying a canoe. Found them used for $30 and use them now when car topping a canoe. I use the foam on the cross bars of my trailer when hauling multiple boats. Blocks for canoes and cradles for kayaks. Boats on trailers ride rougher than boats on the car. Foam provides some give when the trailer bounces.

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