page_title: Block-setting crane
section_title: Later jib cranes
hierarchical_section_title: Block-setting crane / Development / Later jib cranes
context_page_description: A block-setting crane is a form of crane. They were used for installing the large stone blocks used to build breakwaters, moles and stone piers.
  The mid-Victorian age was a time of great expansion in industry and shipping. Better protected harbours were needed, with man-made breakwaters extending beyond natural bays or coasts, in order to enclose safe harbours for the new generations of sailing ships and iron steamships being built. This time also coincided with the availability of large-scale ironworking with which to build cranes, and portable steam power with which to drive them. In contrast to the navvies who had built the earlier canals and the first railways mostly with human and animal muscle power, these new ports were built by powered engines as well.
context_section_description: By the 1920s, port cranes had developed to become much more powerful - particularly when electrically driven, for which Stothert & Pitt were again leaders. A port crane is required to make many lifts, as fast as possible, and so requires powerful motors even if their lifting capacity is not so great. Electric cranes, supplied by electricity from a single centralised generating station or prime mover, could offer a lot of power per crane, without requiring the high cost of an equivalent steam plant on each crane.
  Port cranes were almost all luffing jib cranes, often with a long reach. Their lifting capacity depended on how far they were reaching. Although not intended for lifting heavy loads, when the jib was raised high and the crane worked at a short radius, their capacity could become comparable to a block-setting crane.
  When an existing harbour was to be extended or maintained, it was now possible to use one of the existing port cranes for this work. This only required new lines to be laid along the breakwater and a longer cable supplied to power one of the existing cranes, moved into position for this work. Obviously this was far cheaper than obtaining another specialist crane just for this work.
caption: An electric port crane by Nagel & Kaemp [de] in Maputo, used for breakwater construction. Note the interlocking pre-cast concrete blocks.
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