Its “mast” consisted of two giant pieces of wood in the form of Λ. Its articulation was ensured by two dents in the underside crossbar. Its stabilisation in various inclinations was achieved by two balancing ropes that were tautened with block and tackles and the rear winch (via removable levers). The load was lifted or lowered with the help of two lifting ropes , the “trispaston” pulley and a winch with a horizontal axle, the “reel”, (where the rope for the lifting of the load was wrapped) and rotated (around special bearings, “tortoise – like cases” which were fitted on the mast) with the help of fixed radial levers.

The rear winch was also essential for the lifting and lowering of the mast itself at the beginning and the end of work. The friction between the ends of the axles of the winches and points on the bases ensured their easy stabilisation.

The crane was mounted on rollers for its sideward shifting.

SOURCES: Vitrouvius, On architecture, X.