DESIGN CONSIDERATIONS IN OFFSHORE CATHODIC PROTECTION APPLICATIONS. THE USE OF INTERNAL CATHODIC PROTECTION TO PREVENT INTERNAL CORROSION DUE TO CURRENT DISCHARGE TROUGH ISOLATION JOINTS. As the amount of production water increases as a sub product of the offshore oil extraction, some design considerations must be taken into account while designing cathodic protection systems. This paper outlines the problem of current discharge trough isolations joints by consequence of the highly conductive electrolyte that salt water presents to cathodic protection current. Computer modeling of the phenomena is presented as well as lab testing in real size pipelines with the use of a novel internal cathodic protection system in conjunction with internal coatings.