Foam Blocks for carrying a canoe on car roof

I may be taking about a six-hour trip and would like to take my canoe along.
I’ll be taking a vehicle without a rack and was planning to use foam blocks with slots for the gunwales.
Has anyone had any experience with using these?
Will they be safe on the freeway over long distances?

From long time ago experience: at 70 MPH they will be moving around on the roof.
Jack L

Foam blocks work fine, as long as you use them on a proper canoe rack.

That was my concern

Lots of variables. Speed, type of car, length of canoe, method of securing canoe, etc.

It is pretty hard to say you won’t have problems, but that is true of anytime you put a large object on top of a car.

The single largest thing I don’t care for not having a rack is the way you have to pass the hold down straps thru the door openings. It is hard to beat the double over the hull against a solid rail thing.

If I were going to haul a single canoe on foam blocks only I would rig two cam straps each bow and stern to form a triangle front and back and try and have the slopes looking from the sides so that they oppose. Meaning if it sees a force trying to move it forward or backwards these straps will be in tension resisting the movement.

Then during the trip each time I stopped I would check all 6 cam straps for tension.

I would also try and stay on the low end of highway speeds. The trip might take an extra 20 minutes. I always remember taking family trips down south and passing some slowpoke in an RV and leaving him in my dust. We would stop for gas or a rest stop and when we would get back on the highway sure enough that slowpoke was ahead of us once again.

Definitely doable. Prior to roof racks being common that’s what most folks did, though foam blocks may or may not have been in use. Last weekend I hauled my 15’ solo canoe for an hour at 65mph with a 40mph gusting crosswind on a car with foam blocks on the roof. Worked fine. Was honestly easier than using my pickup with it’s nice roof rack and folding J-racks (which I’d have had to remove to throw the canoe up there, which I didn’t want to take the time to do hence using the car).

Straps through the door openings aren’t ideal, but not a major issue. I used a couple of light duty ratchet straps (heresy I know) triangulated at the bow and stern, which kept it from moving too much in my case.

One thing that I’ve found that really works well when you don’t have an appropriate car with a roof rack, is to make a rectangular frame sized for your canoe/kayak and vehicle out of 3/4 in pvc plumbing with pipe insulation over the pvc tubing and between the four elbows. The pvc pipe is somewhat flexible and fits the curvature of the roof, protects both the canoe and the car, doesn’t move because of the integrity of the tubes and the foam insulation, and the canoe can be fastened through both doors with ratchet straps, and front and back with straps or poly/nylon lines. While you’re paddling, the frame can go in the trunk or interior of your vehicle. Sorry I don’t have a picture handy to show.


For a quick run pool noodles work fine and much cheaper. It is all about straps and getting it tied in well.

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You will probably experience some movement of the canoe but it will be minimized if you use triangulated bow and stern lines, two lines tied off independently to each end of the boat to anchors on the car spaced as far apart as possible.

It will scratch your roof up pretty good