Alternatively, instead of doubling the weight of the counterweight, it could be moved further rearward from the center of rotation to compensate for the increase in the load. (figure 3)

Since adding counterweight is often neither practical nor, in some cases, recommended, true balance of a conventional "fixed counterweight" crane can only be achieved at one specific radius. Any variation caused by changing the radius at which the load is lifted destroys this equilibrium.
While a hydraulic machine is commonly thought to be faster and more positive for materials handling, the same condition exists. Like the conventional crane, the ability to achieve true balance is limited to one specific radius. Secondly, the extra weight of the box type boom structures reduces the crane's net capacity by a considerable amount. For example, a lattice boom crane with a two thousand pound capacity might be reduced to as little as a five hundred pound capacity at the same distance on a hydraulic machine. (figure 4)

And, thirdly, the present boom designs of excavator based material handlers generally include one or more hydraulic cylinders attaching at boom midpoints. The pressures and reactions exerted by the cylinders and loads at these points accelerate metal fatigue often resulting in premature structural failures of the boom. (figure 5)