Abstract: An improved clamping mechanism for clamping a dock support frame having a hollow recess and a U-shaped cut-out to a vertical support member has an anvil clamping member comprised of extruded aluminum. The anvil clamping member has an arc-shaped clamping surface and is fixedly disposed inside the hollow recess in the support frame. A hammer clamping member comprised of extruded aluminum and having a corresponding arc-shaped clamping surface is adjustably attached to the anvil clamping member such that the vertical support member can pass between the hammer clamping member and the anvil clamping member and through the U-shaped cut-out of the support frame.