opposite sides is provided with fixed backstops 37 engageable with coacting backstops 38 on the rear of the jib 13 near its base these contacting backstops positively limit the rearward or upward swing of the jib 13 to the position shown in full lines in fig1 in this fully raised position of the jib the axis of the jib assumes an angle of approximately 0 u00b0 5 u00b0 above the axis of the boom 10 as shown in broken lines in fig1 this invention enables offsetting the jib 13 to two angular positions below the position shown in full lines namely to positions 15 u00b0 and 30 u00b0 below the full line position in fig1 in accordance with the invention these offset positions of the jib are obtained merely by relocating the cable loop guide 21 on the inclined plane bracket 17 utilizing the several pairs of apertures 20 in the bracket as stated the three illustrated positions of the jib 13 are obtained with the use of the one fixed length cable loop 32 and the described simple adjustment of the guide 21 the upper face of the bracket 17 defines the plane in which the cable loop lies and defines the angle of convergence of the cable loop forwardly with the axis of the jib 13 which angle of convergence remains constant in all adjusted positions of the jib the angle of convergence defined by the top face of the inclined plane bracket 17 is preferably about 71 2 u00b0 as illustrated the operation of the invention can be briefly summarized as follows the crane boom 10 is depressed to the lowermost.