Abstract: A boom point construction connects the for and aft mountings of a sheave swivel to the major structural elements of a boom. The boom point includes a framework of elongated members joined together to form a truss. The framework includes assemblies of at least three members joined together at one common point and extending in different directions from the point to define three different planes. Two of the assemblies extend from opposite sides of the front swivel support and another of the assemblies extends from the rear swivel support. A member of the assemblies from the front swivel support is connected to members of the assembly extending from the rear swivel support. The boom point is shown connecting the swivel to a boom having either three or four major longitudinal structural elements.

Abstract: A marine crane having an upper works rotatably mounted on a pedestal adapter, includes a retainer for limiting the extent to which the upper works can be tilted, such retainer having an arcuate member secured to the upper works that extends partially around the pedestal adapter and presents a lip beneath and out of contact with a stationary circumferential member forming a part of the pedestal adapter. The arcuate member has a series of vertical, plate-like buttresses spaced along its circumferential length that have outer ends facing a machinery deck of the upper works to brace the arcuate member, so as to retain the arcuate member in place in the event of abnormal forces being applied thereto.

Abstract: A hydrostatic winch having a hydraulic drive system with a dual control valve which adjusts pressure in control lines for varying the speed of lowering and hoisting a load and a brake for stopping the load has an overspeed control system which includes first valve means for relieving pressure in the control lines and first valve control means which opens the valve to automatically slow the speed of the winch when the load is moving too fast and a fail safe system for smoothly stopping the load, if necessary, which includes a braking system having a normally "off" brake which is biased towards an "on" position but which is held in the "off" position by a hydraulic cylinder.