THE PROBLEM of hull corrosion on steel vessels operating in sea water has always been a major one. The best known procedure has been to apply paint coatings ; however, this remedy has not been altogether satisfactory due to the infrequent intervals at which a ship may be dry-docked for painting and to the difficulty encountered in obtaining paint adherence.
In recent months, work has been directed toward providing a more effective solution to the problem through the use of supplementary protection supplied by galvanic magnesium anodes.
The equipment on which experimentation was conducted was a Chrysler Marine Tractor (Sea Mule) operating in the sea water of the Freeport harbor. This equipment could be dry-docked at convenient intervals for inspection and its construction was such that magnesium anode attachments could be made readily to the hull as shown by Figure 1.
Underwater surface protection consisted of three coats of...