Galvanic anodes for submergible ferrous metal structures

A submerged, ferrous metal structure supported on the floor of an ocean or other body of water, and having a system to provide galvanic protection to the ferrous metal which system comprises a substantially vertically oriented, rigid string of anode units, each anode unit comprising a rigid core and a body of sacrificial anode material surrounding and supported by said rigid core, wherein the ends of said rigid core extend beyond the ends of the body of sacrificial anode material, and are each adapted to be coupled to the end of another similar sacrificial anode unit to provide said rigid string, and said string being electrically connected at at least one end to said structure in a manner to provide galvanic protection to said structure and further comprising a plurality of string guides, affixed to said ferrous metal structure, each of said string guides comprising a tube having an inner diameter greater than the diameter of said body of sacrificial anode material and having a length substantially less than the length of said string of anode units and, within said string, one or more insulating spacers, said insulating spacer comprising insulating material, having a cross sectional dimension substantially similar to the cross sectional dimension of said sacrificial anode material, and cast or molded on a rigid core that is capable of providing electrical conductivity between the portions of the string above and below said insulating spacer, said string of anode units extending through said string guides.