The Figure shows a new design for retractable boom. This so-called crane with luffing jib D.R.P. pend. has a hoist in connection with a rope balancing, whereby upon adjustment of the boom, the load remains the same height. When operating at each stroke of the boom is retracted and designed. The boom is almost balanced in order to lower energy consumption. The advantage of this rocker design is that fast each time lifting a smaller turning radius is possible to turn better at passing ships masts can.