MARINE CATHODIC PROTECTION
Long-term corrosion tests of steel specimens continuously submerged in sea water show that the average corrosion rate closely approaches 0.005 in. per year, while pitting rate is 0.94 in. per year for descaled steel and 9.1 in. per year for steel covered with mill scale or some types of fouling. In very aggressive marine environments pitting is reported to be four times these rates. Failure occurs rapidly at welded seams. Initial perforation of 3/8-in. thick sheet piling must be suspect 15 to 20 years after construction. Structural strength of bearing piles reaches a critical condition long before perforation. The elimination of petroleum pollution in harbours will have adverse efects on harbour facilities as spillage of these petroleum products frequently resutls in float-coating of metal surfaces in the tidal zone thus increasing their protection. A combination of methods is usually required for the control of any single corrosion problem, but cathodic protection is the one method by which virtually complete corrosion protection can be achieved on new or existing subsurface steel structures with prior treatment. It is common practice to provide cathodic protection for many types of marine structures, such as pipelines, hulls, ballast tanks, buoys, offshore platforms, docks, etc.
- Presented by the Pacific Northwest Section of SNAME, April 7, 1977.
Society of Naval Architects and Marine Engineers601 Pavonia Avenue
Jersey City, NJ USA 07306-2907
- Lehmann, J A
- Publication Date: 1977-4
- Pagination: 24 p.
- TRT Terms: Antifouling coatings; Cathodic protection; Corrosion; Corrosion protection; Pitting; Structural steel
- Old TRIS Terms: Fouling protection
- Subject Areas: Construction; Marine Transportation;
- Accession Number: 00170886
- Record Type: Publication
- Source Agency: British Ship Research Association
- Files: TRIS
- Created Date: Mar 14 1978 12:00AM