| 摘要 |
A crane assembly mounted on a buoyant barge has a vertical column with a cross boom, the boom including outer extremities. A trolley is movably mounted on the boom, and has lift means for engagement with articles to be loaded and unloaded. A buoyant counterweight is attached to one of the extremities of the boom by a cable of fixed length, and the other extremity of the boom is secured to the loading and unloading site. The counterweight resists tilt moments on the boom responsive to movement of the weight of the lifted article along the boom, and overturn is prevented in other positions of the article weight by the attachment of the boom to the site.
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