110 and the side chord 114 the supports 128 and 130 are coupled to the inside surfaces of the chords the supports 128 and 130 help prevent the chords 110 and 114 from deflecting due to lacing forces that is those forces occurring during both at rest due to gravity and also by movement of the boom when material is loaded and unloaded the supports 128 and 130 also limit twist and buckling of the chord 110 and 114 fig8 depicts attachment relationships between chords 110 114 and lacings 116 120 and 164 of an exemplary boom 106 the mounting surface 142 of chord 110 defines a first plane the mounting surface 150 of the chord 114 defines a second plane the chords 110 and 114 are arranged so that the first and second plane are generally parallel therefore a perpendicular inter chord lacing 116 attached to the mounting surfaces 142 and 150 will be perpendicular to both chord mounting surfaces 142 and 150 similarly an inter chord lacing 120 will be perpendicular to both mounting surfaces 152 and 162 of the side chords 112 and 114 a lacing 164 connecting mounting surfaces 144 and 160 will also be perpendicular to the plane defined by those mounting.