Boat Electrical Potential

Jeff Betts: How does a Super Betsy flasher set up an electric charge that salmon prefer?

A: A Super Betsy works on the same principle as a Black Box. It has two metals in its construction and one donates electrons to the other, setting up an electrical potential in the medium – salt water – surrounding the flasher. The potential is set at the level that attracts fish to the area. They follow along and when they see the lure, they whack it. Do note that the Super Betsy will start to look tarnished. This is just evidence that it is functioning properly and should not be replaced.

I was posed this question while my column was in the Times Colonist newspaper, and it is below. Currently, I use braided ‘cloth’ downrigger cables rather than stainless steel. There is no electric potential in this set-up, so for me a Black Box no longer works, unless the lines are within 25 feet of the boat, and its electricity leaks. Add more mono before the clip and you can get the tackle farther from the boat.

Reader Ken Evans: I have caught my share of salmon over the years, but since acquiring my new Trophy can’t catch much. Is boat electrical potential the problem?

Answer: The two likely possibilities are: boat electrical potential; and, engine noise.

I had the same problem after changing engines. I put one line on a downrigger at 50 feet and with the other, went with mono line and a two-pound ball, achieving the same depth with 100 feet of mainline. The results were 4- to 5-fish per mono line versus 1 for the downrigger, indicating a problem.

You can check boat electrical potential without leaving the dock. Attach a cannonball and run the downrigger cable down beside the boat. Using a one-volt voltmeter, attach the positive lead to the cable and the negative lead to the engine. If the reading is outside the range of .7- to .9-volts, boat electrical potential is the problem. (This as well as engine noise can be mitigated to some extent by running more mono out before attaching the mainline to a downrigger release clip).

Boat electrical potential results from boat metal leaking electrons into the water, particularly saltwater which is essentially a battery. Electrons flow from the least noble metal – the zincs – through the more noble metals – the reason for using stainless steel - and into the water. This bathes the area around the boat with electricity.

All fish from sharks through halibut through salmon and trout, react strongly to electricity. A shark, for instance can detect the electrical potential of a flashlight battery connected to a lead set 3,200 kilometres apart, an ability difficult to believe, yet true.

Though less acute, salmon respond to the ion bath that extends from one downrigger, the boat itself and around to include all other downriggers where it passes down and out. Commercial fishermen have used the electrical sensitivity of salmon for decades. Their depthsounders register increasing schools of fish. The fish connect visually with the lures and the writing is on the wall. But, change the voltage from the preferred range and the school is ‘blown’ away from the gear, the problem Ken is experiencing.

One’s first chore is to check for electrical leakage from the boat. This includes operating all electric units separately and checking leakage between the off and on position. Even a .05 volt differential presents an electrical leak and can come from something as insignificant as a screw holding down a bilge pump.

Once leaks have been detected and bonding wires installed, other things need checking. Zincs must be new (more than 50% remaining) and clean. Downrigger cable should be less than two years old as it can be etched by minerals and thus electrically fatigued. Cannonballs need to be pure lead; and, among other things, the downrigger spool isolated from boat metal (true for only some brands of downrigger).

Finally, add an electrical device that when connected to downrigger lines, establishes the best electrical potential for each species of fish. Turn the dial and dial in the fish. Chinook prefer .6 volts; coho, .65, sockeye, .75; and halibut, .45. These are recommended starting points. Local conditions may dictate variations.

The sport-fishing product is typified by the Black Box from Scott Plastics. The downrigger cable maintains a fish-attracting positive electric potential because the unit draws electrons from the downrigger cable faster than electrons are donated through the water from boat metals.

Is this just snake oil or something worth investigating? A scientifically sound experiment is not possible, as an electric potential unit will extend electrons around unconnected downriggers. I compared my logbook records before repowering and after, adding a Black Box. After 7 months of testing – from summer into winter - I had caught 134 salmon in 33 trips, a 20% improvement.

My conclusion is that provided a person knows how to catch salmon, and that includes Ken, he or she can look forward to catching 20% more fish. An electric potential unit will not catch fish for a person who does not know how to catch them. The best application is for a guide, whose livelihood depends on putting fish on the line for clients.