Rich, Quoting: "You get a silver/silver chloride cell like this https://boatzincs.com/corrosion-reference-electrode-specs.html <https://boatzincs.com/corrosion-reference-electrode-specs.html> and connect it to your DMM. One side to ground and the cell in the water." This is the procedure for testing for DC Galvanic currents. It will expose DC Stray currents, but it's not really the test for that. This does nothing to detect for AC leaks like the ones that cause Electric Shock Drownings. Quoting: "Even 10 milliamps can paralyze you and cause drowning. Just because you test one minute and find nothing and jump in the marina waters the next minute does not mean that somebody nearby has not energized an AC circuit with a fault the second you were done. Just stay out of freshwater marina waters (at least 50 yards), and don't dive off your own boat with ac power energized. There is a thing on Amazon called shockalarm you could look into." AGREE! NEVER SWIM IN ANY MARINA, FRESH WATER OR SALT WATER! The risk is less in salt water, but not zero. Divers need to be especially alert in fresh water (if anyone dives their own boat). Shock alarms are useful for homeowners and for marina operators. They are not all that practical for individual boat owners. Hope this helps. Jim Peg and Jim Healy, living aboard Sanctuary http://gilwellbear.wordpress.com <http://gilwellbear.wordpress.com/> Monk 36 Hull #132 MMSI #367042570 AGLCA #3767 MTOA #3436