Abstract: In a corrosion monitoring system for an offshore marine platform which includes a deck positioned above the water's surface and a jacket fixed to the ocean floor to support said deck, said monitoring system including cable means extending from the deck to the ocean floor and carrying corrosion monitoring instruments for generating an electrical signal, said carriage being fabricated of such a material to allow generation of said electrical signals without interference or distortion of the latter.

Abstract: Apparatus in an offshore fixed structure for monitoring the effectiveness of an under water cathodic protection system. Said system includes a guide cable, both ends of which are adjustably positioned at the structure's upper end. The cable is retained on a turning spool at the structure lower end to define parallel guide segments upon which a carriage is operably mounted. Monitoring instrumentation carried on the carriage is caused to scan the structure, thereby providing a series of readings which report on the effectiveness of the cathodic protection system.