Kayak Roof Rack Idea

Roof Rack 3D Model

This is my idea for a roof attachment for my new kayak… I’m seeking feedback before building it.

The artwork is crude, but hopefully it conveys the overall idea. The four central fore-aft boards (2×4) sandwich down over the factory roof rails (’05 Subaru Outback, shown in black) with a rubber strip between them using eight hex head bolts. The entire assembly can be removed by removing these bolts.

The lateral crossbars support the load of the kayak and are bolted to the top two fore-aft rails that hold the assembly to the roofrack.

Two more (longer) fore-aft supports run 6 or 8 feet along the length of the car and support numerous tie-downs illustrated near the front of the rack. These would be held in place on the port side by passing them through a hole drilled in the 2×4 and tying a simple knot (not shown). The starboard side would have cam buckles for each strap so that each one can be custom fit to make equal contact with the boat.

This would, I hope, create a hammock that would cradle the boat, while evenly distributing its weight over a large surface area, reducing the likelihood of oil canning. I suspect that the entire cost of the assembly would be around $30 and be superior in performance to more expensive saddle systems which often dent the bottom of the boat. The design only needs to be able to support the weight of the boat since the ripping forces of the wind are supported by the heavier duty straps going over the top of the boat.

Any opinions? Suggestions? Warnings?

15 thoughts on “Kayak Roof Rack Idea”

  1. If you haven’t already done this, I’d make a few changes. I wouldn’t use the four 2×4 sandwich to grab the factory bars. While you could make it tight front to back, it would likely wiggle side to side quite a bit. Also, it would be pretty easy to crush you factory crossbar tubes with that making them very weak. I’d get a set of Yakima MightyMounts #24H(Part # 8003524) that fit your factory crossbars. These will give tight grip on the bars and still allow only a 4 bolt installation. They look like this (http://www.yakima.com/Product.aspx?id=90). Also, I’d skip the 2×4 framing and use 1/2″ or 3/4″ baltic birch plywood (or another veneer core hardwood plywood). You’ll have thinner, stronger, lighter and more aerodynamic pieces. If a particular piece needs to be stronger then double up the wood with waterproof epoxy. If you want to get all fancy use single thickness plywood and wrap in fiberglass cloth coated with epoxy. Sand and paint and it’ll be completely weatherproof and super strong. Also, don’t use a knot in the straps. It’ll eventually come apart. Stitch a loop in the end and pass a piece of flat steel or aluminum through it that can be screwed to the board. Remember to sand down all corners and coat the boards in a good polyurethane. No matter how tight the straps they’ll wiggle a little and will abrade through if rubbing on wood.

    I’ve used and built several racks both homemade and bought. My current is some homemade steel brackets to mount my old Yakima towers and crossbars on the bed of my truck while still allowing use of my soft tonneau cover under the bars. I just lugged a big Yakima cargo box and jogging stroller 400 miles each way on vacation.

    E-mail me if you’d like some help or what I said here was not clear.


  2. Oh, one more thing, remember to design it with the crossbars spaced as far apart as you can for mounting a kayak. It’ll give you the best support possible. And don’t skip the bow/stern straps to the bumpers. They’ll make it more secure than anything else you can do.

    Ok, that was two things, and here’s a third. NO BUNGEES. They are not for securing things on a roof.

  3. Wow… thanks for the feedback! I’ve been debating now. One person responded elsewhere saying that they’d be worried about liability. Even if the rack didn’t contribute to the problem, considering how people will sue for anything. It’s a good point that has me thinking. The bike trailer doesn’t worry me so much since it’s not going 65 or 70 MPH down the freeway!

    As for bungees, yeah, I agree. 🙂

  4. Ah, don’t worry about that. My dad and gpa built a cargo box that was wider and longer than the roof of the old fullsize gm wagons. It was built of 3/8″ marine plywood with steel feet and a canvas cover. We used to haul a 15hp outboard motor (130#+) in there along with everything else. My test is if you can rock the vehicle by shaking the rack and have no slop in the rack, it’s not going to go anywhere. Besides, have you seen what some people strap on top of the cars? We’ve got the junk/garbage collectors around here that stack shit 10′ tall in their trucks with maybe a couple 1″ straps. They’re not on the highway, but they’re still doing 50-60 down city streets.

  5. I now exactly what you’re going through. I own a Subaru Baja and I’m thinking about buying a tandem kayak. I hate to spend so much on a rack when I have the skills to build something custom. My suggestions would be to mount some wheels maybe from some old inline skates or something on the rear of the frame to help you in loading the kayak from the back of the vehicle assuming it’s real heavy for one person. Also, definitely don’t use 2 x 4’s. They usually have knots (Not always visible)and are not really a good choice for something that will receive constant flexing stress. Go with something stronger than pine and be sure to pre drill any holes if any that will get screws. Definetely poly or waterproof it. One weekend trip out in the elements plus salt water is all it will take to start fading. I may sound over cautious, but the last thing you need is to have a small crack turn into a big one and invent the worlds first flying Kayak!

  6. Liability concerns worried me… so I went out and bought a Yakima Hullraise Aero at REI. Not even 5 miles down the road the mounting bracket and bolts bent over and my kayak was hanging perilously off the side of my car at 65 MPH on the freeway!!! Yikes! The rack said that it was good for up to 150 lbs, and my boat is only 80!

  7. Rex, I would just like to say that I just purchased a kayak and was looking for an inexpensive way to mount it to the roof of my Explorer. I really liked your design posted on this page so I went ahead and made a mount very similar to yours. I just made a few changes, but for the most part it is the same. I must say that the roof mount works great. The kayak dosnt go anywhere and the mount dosnt slide at all. It is a great design. So i would like to say, thank you for the help.

  8. I am of the same mind to build my own roof racks. Using the same concept except using some slightly differant materials. My car will accept u-bolts to secure the cross support. I located the rectangular type which fit better and require less clearance. Secondly, I am looking at using two fore/aft supports which would support the hull port/starbord for a measured distance. The tie downs are then over a longer distance and less chance for movement.

    Yea, bungee cords are really a no no. They can be fine to help stabilize but not your primary support. Go gorilla to hold everything on the roof.

  9. Looks incredibly heavy, and totally unnecessary. If you have a factory roof rack simply slap your boat on it upside down and strap it down with ratchet straps from your local hardware store.

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