Harry, my Magnum wings have that support bar. (see picture)I also have anchor support plates at each hull & crossbar connection. I use the 1/4" ss bolts to lock them on. Just need to know if I should add the support bars to stop the fore and aft motion of the wings in large waves. (standard retrofit for the SX wings). Hobie said that they were not needed in magnum wings.

All Hobie 18 wings (Magnum and SX) bolt on any Hobie 18