We prefer these simple nylon covered foam pads to expensive roof rack cradles or rollers. They slip over Yakima, Thule, and most narrow factory racks. Velcro tabs and tie-downs are sewn in, so they won’t blow off.
At 18" in length, two pair will fit side by side on a 50" cross bar. For wider factory-type roof racks order the Aero Roof Rack Pads.
Available in a 30" inch pad for your wider boats.