Abstract: A drill mast has two tubular side chords and a central chord equally spaced from the side chords. The central chord is joined to the side chords by transverse and diagonal tubular lacing members. Space frames formed of tubular members extending from spheres are connected to each of the chords. The spheres are aligned along a line equidistant from the chords.

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.