The protective properties of inorganic zinc rich paints were tested over 18 items, and the following results were obtained.
The consumption rate of film thickness of these coatings is estimated to be 10μ per year in sea water. Active paint has a high protective ability by virtue of high loading of zinc, but zinc consumption rate is high, and accordingly it is inadequate as primer to be applied under paint of poor alkali resistance. Inactive paint consists of zinc and other inactive pigments such as aluminum, talc or iron oxide and its zinc consumption rate is lower than that of active paint, and so its service life is rather long. In addition, with application of this inactive zinc primer, the service life of organic anti-corrosion coating system can be prolonged. On account of their inorganic characteristics, these paints are gifted with excellent performance in high temperature and can be good choice where solvent resistance is required.

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The customary cathodic protection systems applied to the submerged or buried steel structures which face to frequent change of corrosive environment, show sometimes unsatisfactory results.
For example, in the ship hull protected by cathodic protection and coating, current requirement varies in wide range corresponding to the conditions of coating, and the current fluctuate widely by navigation, stop and the change of conditions with the lapse of time.
The customary cathodic protection system cannot follow the demand for variation of current requirement, and therefore the automatically controlled cathodic protection system is required.
In the two examples given in this report, the automatic control system, composed of zinc reference electrode, A. C. or D. C. amplifier, and S. C. R. power controller, was applied to the hull of a ship and the ballast compartments of another ship, and its good operation result was shown.
In the case of a 6, 600 DWT lumber carrier, to keep the hull at the protective potential of-850mV, 40 amperes was needed on one side at the time of maiden voyage. After one month, the current decreased to 10 amperes during navigation and a few amperes was sufficient during anchorage.

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