A LABORATORY SIMULATION OF THE GALVANIC CORROSION OF A SHIP HULL PLATE BY SHAFT GROUNDING SYSTEMS

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Authors
  1. Huber, T.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
The use of modern impressed current cathodic protection and shaft grounding systems have substantially reduced the corrosion of the underwater hull and propellers of HMC Ships. However, there have been circumstances in which the shaft grounding system has been left on while the cathodic protection system has been turned off. This has led to increased corrosion of the hull plate, both because of the inherent difference in potential between the steel hull and bronze propellers and because of the differences in the rates of delivery of oxygen to these surfaces. A laboratory simulation has been developed in an effort to determine the extent of galvanic corrosion that occurs under these circumstances. The effects of different relative velocities of impinging natural sea water on the galvanic corrosion of hull steel (350WT) coupled to a bronze propeller were quantified with a zero resistance ammeter data acquisition system. The effects of relative surface area and different propeller materials were also measured. The results were extrapolated to estimate the length of time the cathodic protection system could be shut off before hull perforation could occur.
Report Number
DREA-SR-97-002-PAP-13 — CONTAINED IN 98-00986
Date of publication
01 Oct 1997
Number of Pages
16
DSTKIM No
98-00999
CANDIS No
507216
Format(s):
Hardcopy;Document Image stored on Optical Disk

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