Critical Design Issues on the Cathodic Protection Systems of Ships

  • 발행 : 2007.06.01

초록

Cathodic protection technology has been widely used on ship's outer hull and inner side of ballast water tanks as a supplementary corrosion protection measure in combination with protective organic coatings. Impressed current cathodic protection system is typically opted for the ship's hull and, sacrificial anode system, for ballast water tanks. The anticipation and interest in cathodic protection system for ships has been surprisingly low-eyed to date in comparison with protective coatings. Computational analysis for the verification of cathodic protection design has been tried sometimes for offshore marine structures, however, in commercial shipbuilding section, decades old design practice is still applied, and no systematic or analytical verification work has been done for that. In this respect, over-rotection from un-erified initial design protocol has been also concerned by several experts. Especially, it was frequently reported in sacrificial anode system that even after full design life time, anode was remaining nearly intact. Another issue for impressed current system, for example, is that the anode shield area design for ship's outer hull should be compromised with actual application situation, because the state-of-the-art design equation is quite impractical from the applicator's stand. Besides that, in this study, some other critical design issues for sacrificial anode and impressed current cathodic protection system were discussed.

키워드

참고문헌

  1. S.Evans, Material Performance, 27(2), 9 (1998)
  2. J.C. Cochran, Proc. of Offshore Technology Confernece., Paper OTC 3858, Houston, USA, May 5-8 (1980)
  3. M.W. Mateer, CORROSION/93, Paper No. 526, Houston, USA (1993)
  4. J.H. Kiefer, CORROSION/98, Paper No. 735, Houston, USA (1998)
  5. W.H. Hartt, Corrosion, 52(6), pp. 419-427 (1996) https://doi.org/10.5006/1.3292129
  6. W.H. Hartt, Corrosion, 54(4), pp. 317-322 (1998) https://doi.org/10.5006/1.3284858
  7. Recommended Practice, DNV RP B401, Det Norske Veritas (2005)
  8. Recommended Practice, NACE RP 0176, NACE International (2003)
  9. Recommended Practice, DNV RP B401, Det Norske Veritas (1993)
  10. Recommended Practice, NACE RP 0176, NACE International (1994)
  11. Guidelines for Ballast Tank Coating Systems, The Tanker Structure Co-operative Forum (2000)
  12. O. Knudsen and U. Steinsmo, CORROSION/200l, Paper No. 01512, Houston, USA (2001)
  13. S.Chen and W.H. Hartt, Corrosion, 58(1), pp. 38-48 (2002) https://doi.org/10.5006/1.3277302
  14. Recommended Practice, NR-423-DTO-R00-E, Bureau Veritas (1996)
  15. Code of Practice for Land and Marine Applications, BS 7361, British Standard (1991)