Dave's kayak storage video yesterday gave me some inspiration. My house is on a river and always has kayaks littering the yard. I needed a rack to hold more than a few kayaks, and one that could be moved around as needed. I came up with a design that can hold 8 (or even 10) kayaks and paddleboards, and built it in a single morning.
I used whole 10' conduit sections as legs, with 3' bent for feet. The legs on each side are connected by 5' crossbars using t-connectors. For the racks themselves, I used 5' sections with a 15 degree bend about 3" off center on each side. These are connected to the legs about a foot apart vertically using cross over clamps. The leg-foot braces are 2.5' with 45 deg. connectors. Very simple, with minimal cutting and no waste since everything is 10'/5'/2.5'
