Couldn't find oarstands for 1.05 OD frame tube (I'm building a superlight play frame with single side rails). Thought about drilling extra holes in the NRS towers. But instead I dug around in the bin of 6061 at the salvage yard and found some nice T-rail, flat, and square billet stock (about $2.50 for a boxful).
Shaped the parts with a hacksaw, drill press, and various files. The holes were already drilled in the T-rail so I cut that piece to use them. The two holes in the strut are for carabiners, rescue bag, etc. The bevels on the oarlock socket are to allow the welder to get a decent bead.
Definitely shop around for the welding job. $85
— think I got gouged, but the guy is a boater and I like his dogs.
Here's the end product, with two 1/4" x 1-1/8" u-bolts for grip on the single rail.
Here's the pair. Cost $98 plus 4 hours of my labor.
Just found out that Sawyer makes Mini-Cobra locks with 1/2" shanks that weigh about half what the full-size ones (with 5/8" shanks) do. So I'll look for a bushing I guess.
Anyhow, I like doing this trash-into-treasure thing.