Off shore structures

Claim 1

A tower structure adapted to be supported on a bed beneath a body of water with the upper end of the tower structure above the surface of the water, said tower structure comprising a rigid top frame, an even number greater than four of straight tubular columns, an annular polygonal base support member for resting on said bed having the same number of sides as the number of said tubular columns, said columns sloping downwardly and outwardly from said top frame to said base member, said columns being secured at their lower ends to respective apexes of said base member and at their upper ends to said top frame and having a length predetermined to extend adjacent or above the surface of the water, and an even number of similar sets of coplanar tubular bracing members respectively interconnecting each pair of adjacent columns, the bracing members of each set being arranged in a zig-zag pattern without intersecting each other but with adjacent ends of adjacent bracing members of each set secured to the respective column of the pair at the same anchor point, with the axes of said bracing members substantially intersecting the axis of said respective column at each said anchor point, not more than two bracing members of each set meeting a column at any anchor point, one such bracing member being inclined above the horizontal and the other below the horizontal, the anchor points on each column for the two sets of bracing members connected to the column being in register.