Armor unit

An armor unit for stabilizing rubble mound structures such as coastal revetments, breakwaters, and the like, comprising:

• a central configuration having a length, a width and a depth, dimensions of which said length, said width and said depth are established by dimensions of right frusta of identical dimensions, each said right frusta having at least sides and a distal base said distal base having an area defined by an angle, α, of uniform taper of the sides of each said right frustum from said central configuration and a height, d, of each said right frustum and a square proximal base establishing both said width and said depth of said central configuration, said square proximal bases of two abutting said identical right frusta establishing said length, said central configuration having two ends established by said width and said depth and four sides established by said length and said depth, a first pair of parallel said sides established as top and bottom, respectively, and a second pair of parallel said sides established as the sides of said central configuration, said top and said second pair of parallel sides incorporating two said identical right frusta on said top and each side of said second pair of sides, said ends incorporating one said identical right frusta on each said end of said central configuration;
• and
• fillets of depth, t, applied as inverted triangles coming to a point where said proximal bases intersect for each said pair of right frusta, said t<said d, said right frusta cast integrally with said fillets and said central configuration in a first casting,
• wherein, said fillets minimize internal stress levels of said armor unit;
• and
• at least one extrusion incorporated on said bottom of said armor unit, wherein said at least one extrusion is cast separately from said first casting, and wherein said separate casting permits said first casting to be cast on a flat surface thereby reducing internal stress levels on said armor unit, and
• wherein said uniform taper facilitates removal of a mold for casting said armor unit.