DIY Truck box kayak carrier

Recently we purchased some Canadian Tire special kayaks. High end right? Most of the summer we have been pulling them around on the utility trailer or in the back of the truck. This has worked fine until we had to head to a family reunion and decided to stop for a weekend in beautiful Jasper Alberta. We wanted to take the kayaks with us but we are also pulling a travel trailer thus necessitating alternative arrangements for carrying the kayaks. After some online research I discovered that most truck box racks clamp to the bed rail but my truck has a tonneau cover which I really like having. I found one that uses an adapter to put into the stake pockets but the total cost of it was something in the neighborhood of $1600. I felt stupid about forking over 3 times as much money to carry them as the kayaks cost in the first place so I decided to build one instead. So for $30 of wood (eight foot two by fours) and $50 worth of u-bolts and carriage bolts I built this.  
Originally I had intended to put the back level with the front but I had cut all the risers to the same length, not thinking that the various bits of hardware holding the tonneau cover on would interfere. In the end the back bar ends up about 3 inches lower than the front. This meant I had to do some tricky compound miters to get the cross braces to fit but it actually turned out better that way because it lifts the front end of the kayak a bit more and gives it better clearance over the truck cab.

All in all it took me about 5 hours with pretty basic tools. I used my circular saw, hand saw, chisel and drill. I used a miter saw to do the complex angles but I could have done it with my hand saw. I bolted most of it together to provide some ability to tighten it up as the wood shrinks. 

It works but if I was to do it again I’d add another 4-6 inches on the front rail. As it is it’ll be easy to replace if I decide to. Tomorrow I’ll post a couple more pictures with a close up of the joints and with the kayaks on for perspective.