Black Boxing

[Brewcrafter]

Subject came up in another thread, and since it was something I am unfamiliar with (but some of the very experienced Ohana were singing the praises of) I figuered I would explore a little bit.  I immediately ended up at the website for the company that sells and promote the systems, and they had a LOT of information.  I also hit some other independant studies and so far this is where I am at:  Many fish can be sensitive to minute electronic currents and voltages.  How this manifests itself into a bite reflex I am still not sure I understand.  Now I do understand (after having replaced enough sacrificial anodes) that the solution we are playing in (saltwater) is electrolytic.  Where I get confused is that one paper said that while gamefish can easily detect currents, the distance for this is Centimeters, NOT meters (so they would have to be right on top of the bait) and also, while these systems seem to tout being able to ensure a fixed voltage is being sent through the water, I know that the medium (saltwater) varies in salinity, density, and temperature; all factors which would change the voltage requirements in my mind (I have done some electroplating).  Also reflecting on the Degaussing station down in San Diego just past the bait receiver 9of course the goal there being to eliminate any electronic/magnetic signiture - key in a warship).  Anybody care to weigh in with their experience and why it should work? - john

[Swami805]

There were some big marlin trolling lure that used some kind of electric pulse, the name EAL maybe?  I remember they were expensive but I don't think they were a game changer

[Dominick]

The "Rotary Salmon Killer" lure had a chip on it that supposedly gave off the electrical current of a distressed fish, thus resulting in an electrical attraction.  In my experience it did not get bit anymore than the salmon killer without the chip. For those of you who are not familiar with the salmon killer go to (https://www.protroll.com/the-orig-rot-salmon-killer)  I think attaching an anchovy to the clip is what does the trick.  Also the lure rotates and slightly zigs and zags, this combination seems to do the trick.  BTW the lure comes in different colors so back to rods and cones  . Dominick

[Brewcrafter]

Dominick - You're a little too young to remember this  , but back in the "pre-interwebby" days on some of the really marginal channels on TV (Channel 11 and 13, mostly) I remember seeing commercials marketing bass lures that used what at the time we called a "watch battery" (and now that everyone has a phone, nobody wears a watch, and we are older we call "hearing aid batteries") with the thought being it transmitted a tiny charge of current to make bass strike.  Haven't seen anything like that in years.
I read everything I could find about Black Boxing (some of the manufacturer information was pretty detailed, but then again they are the folks SELLING the idea), then read a bunch of various "non AT" forums and pretty much summarized this as "does it hurt, no, does it work, maybe, so do it".  Like a lot of other stuff we fisherman do.  Then I went and ran the question past my fishing buddy who is both a top-notch boat owner and also has had a long career in electronics.  His first thought was a prevailing belief that a large majority of folks that have issues with boats boil down to having improper, inadequate, or poorly maintained grounding.  He pointed out to me that the harshness of the environment, coupled with constant vibration, pounding, etc, make it virtually mandatory to go through regularly and check the entire boat to insure connections are solid, clean, and tight on a regular basis.  Since 99% of what we do is fish down here, black boxing really wouldn't apply to anything we do but still nice to try and understand anyway.  As such, he has a pretty high end multimeter so next time we go out when the fishing is slow the plan is to play around a little and see what we can learn. - john

[Keta]

His first thought was a prevailing belief that a large majority of folks that have issues with boats boil down to having improper, inadequate, or poorly maintained grounding. 

Yup, a hot boat does not fish well.  I have fixed a few boats FACTORY wiring that were grounded through the hull.  Proper grounding and zinks are not that hard to do.

[jurelometer]

Glad that this topic got its own thread so it can stretch out a bit.  Hope to hear more from the salmon trolling folks here.

Here is the only study that I could find.  It was mentioned in a manufacturer's website.

https://open.library.ubc.ca/media/download/pdf/831/1.0094748/1

The results were a bit all over the place. The paper claimed some statistically significant increases and decreases in catch rates depending on before/after voltage levels, species, and size/age.  If I remember correctly, they claimed that school density did not matter.

The construction of the experiment was a bit curious in that two different voltages were tested at the same time, one on each side of the boat. I don't know anything about electrical fields in water, but if the fields are not extremely small, the experiment was compromised, as one side was affecting the other.  And if the fields were tiny enough not to affect each other, then any black box effect would only occur when the salmon was touching or  extremely close to the lure.  Which implies how conductive the lure is, leader length, etc, might also play a role in BB effectiveness.

It would be nice to see some other studies.  This is the sort of thing that could actually be tested in a way that yields useful data.

A question: At least in this experiment, the results were most dramatic when there was a decent sized swing in between negative and positive voltage — consistent with Lee's point about proper grounding being a big part of the battle.  And with spectra becoming a more common replacement for stainless cable for downrigger line, I assume that there is no voltage on the downrigger line, so no opportunity to use a black box, and maybe less of a need as well?

-J

[Keta]

There is a high probability of some curent passing through the electrolyte (salt water)  between a lead downrigger ball and a aluminum hull with semi non conducting braid  "cable" and braid absorbs water making it somewhat conductive.  A SS attachment to the ball might "short circuit" the loop but SS and aluminum are not close on the nobility scale and could add to the potential problem.  This is just a semi educated guess though as I know far more about active cathotic protection and zink on stationary structures (AMHS steel docks and other related infrastructure) though, similar but not the same.

[jurelometer]

Wet PE braid in the air - OK- as that would be the path with the highest electrical potential. But underwater, wouldn't the greatest potential be from all of the water?  Braid in this environment would simply be a bunch of non-conductive PE fibers dipped in a conductive liquid.  Why would electrical current travel down the least conductive component? 

I am confused (again )

-J

[whalebreath]

Wet PE braid in the air - OK- as that would be the path with the highest electrical potential. But underwater, wouldn't the greatest potential be from all of the water?  Braid in this environment would simply be a bunch of non-conductive PE fibers dipped in a conductive liquid.  Why would electrical current travel down the least conductive component? 

FWIW-Commercial Salmon trollers Do Not use spectra fiber cable-ever.

[Patudo]

What do they use, and what's the reasoning for it? 

[Keta]

Stainless steel  cable.