GB1039178A - Improvements in derricks for ships - Google Patents

Abstract

1,039,178. Ships' derricks. A. E. HALLEN. Oct. 3, 1963 [Nov. 9, 1962], No. 39047/63. Heading B8B. Arms 5, 6, Fig. 2, which carry topping-lift guide-pulleys are universally pivoted to an athwartships beam 4 of a ship's derrick and restrained in their pivotal movements by cables 8, 9 and 10, 11 respectively. The lengths of the arms and cables are such that the boom can always be swung back from a position over the side i.e. the arms do not swing further inwards than the position of arm 5 in Fig. 2. The topping lifts 13, 14 are wound on winches 15, 16, Fig. 1 (not shown), and a load fall 29 is wound on a winch 32. Alternatively, the topping lifts may pass from one winch to the other and be wound in the same way on one and opposite ways on the other so that one winch luffs and the other slews the boom. Fig. 5 shows an arrangement with a shorter athwartships beam in which arms 5, 6 are supported by two cables and two rigid arms 43, 44. These latter arms are attached to arms 5, 6 by sliders 45 to permit limited movement as before. The arms 43, 44 may be telescopic. Fig. 6 shows an arrangement for heavy loads in which each topping lift comprises two parts, e.g. three runs 14<SP>1</SP> between the boom head 12 and the arm 5, one of these passing to a winch, and two runs 14<SP>11</SP> between the boom head and the midpoint of a beam 4. During slewing the length of the parts 14<SP>1</SP> only is changed. For use with lighter loads operation can be speeded up by detaching the parts 13<SP>11</SP> (not shown) and 14<SP>11</SP> from the beam 4 and attaching them to the base of the boom. The swinging arms may be used with dual masts or attached directly to the ship's superstructure.