WORKER WAS ON TOP OF A DUST COLLECTOR SETTING A 90 DEG HOOD IN PLACE. WORKER WAS TIED OFF TO VESSEL. WHILE SETTING THE HOOD, IT SHIFTED & PUSHEDTHE WORKER OFF THE SIDE. HIS HARNESS SWUNG HIM I NTO THE SIDE OF THE VESSEL CAUSING BRUISES. THE HARNESS STOPPED HIM FROM FALLING TO THE GROUND HOLDING HIM ABOUT 3 FT OFF THE GROUND