[jorluivil]

OK, all kidding aside. If you're planning on heading out in open water hanging them off the side regardless of whether you use aluminum or not will cause to much of a strain on the rack and the boat. I was a private boater for roughly six years, I know what it's like to be on a boat that is constantly pounding waves, crossing the Catalina Channel at 2pm is no joke. If my feet and boat took a beating from the constant pounding of the boat I can't imagine what kind of strain you would be putting on a rack that hangs over the side. I would recommend you just strap them to the bow, tow them or lean them on either side of the boat.