Corrosion Monitors – AC DC Marine Inc. Metal parts underwater are subjected to two basic types of corrosion: galvanic corrosion & stray current corrosion. Your boat, propeller, & motor may be harmed if not correctly monitored with AC DC Inc. instruments and avoided. Galvanic corrosion caused by nearby grounded steel structures may occur when you dock your boat & use shorepower. Marine Corrosion Meter – AC DC Marine Inc. The AC DC Inc. Marine Electrolysis Monitor is designed to detect galvanic corrosion in fiberglass pleasure boats. The system can be used to test all electrical equipment, battery chargers and on board appliance for increasing galvanic electrolysis.