Boats & electric fields?

[garyk]

I thought awhile back there had been a thread here on the topic of boats, electric fields, measurements, and cures like 'black boxes'?

I couldn't find anything in the archives.

Does anyone know the keyword to search on?

If I'm wrong about the prior thread, does anyone have thoughts to share on the subject?

[Jeffhead]

I have one and in the salt wouldn't fish without it. For more info follow this link http://www.scotty.com/scotty_blackbox.htm Haven't done much research on how it works in freshwater as I don't run the riggers' in the rivers. I have heard that thet are used over in the reach for the fall nooks'.
Good luck and tight lines, Jeff [img]images/icons/grin.gif[/img] [img]images/icons/grin.gif[/img]

[Pilar]

I can't find it either. There was something I posted a few months ago about this subject.

Feel free to spend $$$ for the commercial unit. There is a way to do this if you can use a solder iron and read a simple circuit diagram. The result is not adjustable and does not flash on and off but it costs less than $10. I can't imagine dragging downriggers without it.


The last time we did this a few people gave me their fax # and I sent out a hand drawn sketch and parts list. I dont have a net ready version. This stuff can be had at Radio shack off the shelf. Homemade is good!

Anyone interested?

[Threemuch]

I would be interested in the diagram. I agree, homemade is good!

I usually fished downriggers in the salt for salmon, but never with a black box. I always made sure my cable was isolated from the weight and the cable had a zinc on it.

On days where everyone gets their fish, a black box means nothing. On days where no one gets their fish, a black box means nothing. But on those days where it is scratch fishing, and only the skilled and lucky go home bloody, I would rather have it. Especially if I can make it for 10 bucks.

[Slow Roll]

Count me in too Pilar, never hurts to be prepared when the time comes. Besides I love building little gadgets, gizmos and whatnots. [img]images/icons/cool.gif[/img]

Paul

[garyk]

I am certainly interested in seeing the plan.

Where I was coming from though, was not about fishing downriggers but just plain trolling in the salt -- South Jetty style.

Our relatively new aluminum boat fishes well in fresh water, but in the salt it seems to have a 'fish exclusion zone' surrounding it.

I know one well repected guide has some sort of box on his sled, even while fishing upper Tillamook Bay.

The possible fact that we simply suck at salmon fishing seems too simple an answer -- the Truth must be out there!?

[DK]

pilar, count me in please, dk

[Pilar]

GaryK. I have one of those plastic boats. The black box is attached to a stainless steel electrode that is wet all the time. I also connect it to the downrigger wires whenever they are wet. You would need to fashion an insulated electrode and do the same thing to put a positive electric 'field' around your boat.

This technique works in any conductive water. Just realize that fresh (IE: river) water is much less conductive than salt. You still get a field it is just smaller.

I'm still searching for the original post. It happened around mid June.

Found it! http://www.ifish.net/cgi-local/ultim...c&f=1&t=005067

BTW the last time I checked the voltage on my downrigger wires it was + 0.67 volts DC in the Pacific ocean at the Rockpile. The ball was at 100' depth and the Ocean was 54 degrees F. It varies and depends on water conditions and current flow through the device.

[ 10-02-2001: Message edited by: Fishin Dude ]

[ 10-02-2001: Message edited by: Pilar ]

[garyk]

Thanks for the link to that past thread.

It's the enhanced conductivity of sea water that got me thinking about this potential problem.

To measure the voltage of the hull or surrounding it, do you just put a voltmeter on the hull?

Looks like quite a few would like to see the plans for your black box. Thanks for the info?

[Pilar]

If you can wait till tomorrow, Threemuch is going to digitize the sketch and post it. If not, E-mail me and give me your fax #.

It works! this ain't no *****.

The voltage check is between the negative post of your battery and the item you wish to test. Ideally the hull of your aluminum boat should be at the same potential as the negative side of your battery. At the very least the engine and related parts should be at this level.

You have to figure that Aluminum is a good enough conductor to make this especially true on a beer-can boat.

Important point! The electrode you use for your field generator (black box) should be of stainless steel and insulated from the hull.

[ 10-03-2001: Message edited by: Pilar ]

[Kerry]

I sure would like to look at the diagram also, Thanks

[garyk]

Thanks for clarifying that the test is made between the neg. side of the battery and the object in question.

We'll be on Tillamook Bay tomorrow and the voltmeter will be along for the ride. I'm
interested in seeing what the measurements are.

Look forward to seeing your sketch when we get back -- thanks again!

[HOGTIDE]

I believe I read an article , not too long ago, in F&S, about Great Lakes downrigger fisherman intentionally transmittting an electric field from their downrigger cables to improve the 'bite'. The premise was that certain levels of current actually catch the fishes interest. They spoke of commercial 'boxes' that sent the proper 'pulses' down the cable.

.....don't think I dreamed this up. Have you heard of it?

I assume this discussion has been about neutralizing the current???
[img]images/icons/confused.gif[/img]

[ 10-02-2001: Message edited by: HOGTIDE ]

[Pilar]

Hogtide, the desired field is Positive in polarity and from 0.4 volts DC to 0.9 volts DC. The dissimilar metals present in most boats cause a variety of electric fields of either polarity. These can be conducted onto your downrigger wires and give your gear the wrong 'flavor'. The effect noticed by the fish is electrical potential or charge.

The whole point of the 'Black Box' is to force the wire to have a slight + charge. Research shows that the Salmonid fishes are sensitive to electric fields and use them to locate prey. Sharks also do this as do some other fishes. It is one of the senses fish have in their lateral lines. The electric fields can attract or repel depending on polarity and magnitude.

Schooled bait fish give off a slight + charge and so the preffered setting is about positive 0.6 volts DC. Luckily for us a simple and rugged diode (1N4001 or equivalent) maintains this voltage across its terminals when it passes current. Add a resistor, alligator clip, electrode, switch and a fuse to limit and control the current draw and wa la you have a black box.

The commercial versions use a BJT (transistor) and can vary the voltage of the field with a rheostat control. They also often include a meter so you can see what it is set at. I went for simple (cheap) and used the diode junction voltage to hold the electric field potential at between positive 0.5V AND 0.7V, depending on conditions.

One of the long time top guides, Bob Toman, was the first I know of to use something similar in T-Bay; as far back as the early 80's. It usually has enough salinity to use what he did back then.

More recently I've learned more about this from my friend and saltwater fishing effectionado Jeff Whitehead (Jeffhead). He is a firm believer in the Scotty black box we used in Puget waters succesfully. However, I am not convinced about the freshwater version Scotty has trumpted up on it's website. Anyone in the know about freshwater use willing to share with us? Thank you.

RT

[Threemuch]

Here is pilar's black box!



I am definitely going to build one. I may monkey with the resistor value or even put in a potentiometer for adjustable voltage.

Thanks John!

OOPs! turn the diode around or it wont work! Sorry for the bum dope.

[ 10-09-2001: Message edited by: Pilar ]

[Pilar]

I'll see if I can get it into CAD, convert it to a bit map and post that. This one is a bit dark and hard to read.

You could use a potentiometer but it will have little effect on the voltage. That Diode will maintain about 0.6v across it's terminals no matter what, until it smokes. Just a property of the device and very hard to overcome.

The parts list

3 amp fuse and holder
1 pole, 2 throw lighted switch w/ bracket
200 ohm, 2 watt resistor
1N4001 (or equivalent) diode
10' of 14ga. wire
alligator clip


Build it just like shown. Use heat shrink and liquid tape if you know how. Saltwater plays **** with electrical things that are unprotected. Don't forget the resistor to limit current flow or you are building a fire. The Diode will pass current with wild abandon without the resistor. If you use a permanent stainless electrode, connect it where the alligator clip is hooked up.

One last tip. Leave this thing off unless you are fishing. It will use up your zincs at a pretty fast pace. I'm thinking of what would happen if you were moored and left it on. For a few hours a trip while trolling the electroysis effect is not noticeable.

[Jeffhead]

I am a firm beliver in the box. Having some voltage control is better than nothing, but if you could/would add the reostat to the ones you are building and get total control it will be more effective. Lot's of variables but I have found that nooks' like the setting around .625 and that silvers around .675. Less than that and there really is no attraction for the fish, more than that and you will "blow them off" and push them away. If you are going deep you will need to jump up the voltage about .5 for every 100 ft of rigger cable out due to line loss.
Good luck and tight lines, Jeff [img]images/icons/grin.gif[/img] [img]images/icons/grin.gif[/img]

[FallRiverGuy]

RT,

A few guides I know that target Kokanee will not fish without the black box. I have another friend that was fishing with one of the guides, and being a skeptic, did not believe in the black box. The guide played around with voltages and affected the bite and the number of fish passing under the boat as seen by the fish finder. Needless to say, but my friend became a firm believe in the unit for Kokanee.

I do not have one because the electric field on my downrigger cable is at 0.7 V and I figure that is close enough not to justify the $ Scotty wants. I am, however, interested in making my own and giving that a try.

[Pilar]

Sureset, ignore the extra post. For some reason a small single pole, single throw is hard to find in the parts store. Use the center post and either side.

[SureSet]

It's been a while, but looking at that diagram I belive that's a Single Pole/Single Throw (SPST) switch not a Single Pole/Double Throw (SPDT) switch. Some might wonder what to do with the extra lug on the switch they bought. [img]images/icons/wink.gif[/img]

SureSet

[jcarufo]

I was surfing E-Bay about 6 months ago and found a gentleman locally (in Oregon) selling a 'Black Box' that was origanilly designed for commercial trollers. It's called 'Electrocatch' and is a sealed waterproof polymer unit with a built in meter. It isn't adjustable, but is designed to put out .6 volts. It seems to work great. Included in the package was most all the wiring required and a report by the OSU Sea Grant Program done in 1975 about the "Bonding of Boats and the Adjustment of Trolling Wire Voltages". Very informative. No spam intended as I don't even know the seller, but I know there are more, so if anybody's interested I'd be glad to provide his E-Mail address to you and/or copy the report if you'd like. The unit was cheap! My e-mail address is jcarufo@pacifier.com. Have a Great Day! Tight Lines,
jean

[garyk]

Jean, you say your Ebay box works great. Are you using it with downriggers? Or just to put a charge around your boat?

[Jeffhead]

Gary,
You need to be running riggers' with stainless steel cable. It is the difference in the nobility of the disemilar metals that creates the electrolisys field. Stainless has a nobility of .24, where zinc has a nobility of 1.04. If ya do the math 1.04 - .24 you have the potential for a .8 positive voltage between the 2. Using the same formula aluminum alloys have a nobility of .71 so 1.04 - .71, so just using your boat the available field will only be .3 positive voltage. The Scotty black box let's you know when you turn it on what the natural field is around your boat, if it's below .7 either you need more zincs or you didn't wire brush the zincs (with a SS wire brush) you have before you went out that day. If it above .9 volts you probably have some sort of leakage out the hull and will be blowing off the fish. I would not hesitate to go and buy the black box, it gives you the most flexability do dial in for any given spicies of salmon or trout that you will be fishing for. And no I don't work for Scotty, I just know they work. There are days on Puget Sound that the fish checker has 4 fish for 50 boats and 2 of those fish were in our fish box. Like what was said earlier in this thread it dosen't matter when everyone is catching, but it sure does help when things are slow.
Good luck and tight lines, Jeff [img]images/icons/grin.gif[/img] [img]images/icons/grin.gif[/img]

[StorminN]

A number of years ago, a friend lent me a book called "Fishing With Electricity" by Ollie Rod (sp?) he's a Canadian author from the Victoria area.

Most of this "positive voltage attraction" stuff was originally developed in the Canadian commercial power troll fleet, maybe as early as the late 60's. I've heard that from a couple of sources, one of whom was a troller out of Westport in the 70's.

Anyway, this book was published in the early 80's and the subject was using positive electrical fields to attract fish, with downriggers or even just lures. He said the reason brass, and to a greater extent, gold-plated spoons catch more fish than painted lures is because they are noble metals, and give off positive ions as they are dragged through the water. He said if you want to increase the voltage that a spoon like this gives off, then you should electrically connect it to a less noble metal, like zinc. He gave examples of trolling (without downriggers) zinc crescent weights (instead of lead) using an insulated wire leader, attached to the gold plated spoon.

He talked about separating the positive and negative nodes with insulated wire to increase the size of the attractive field. He said that ideally, if you were using a downrigger, the best setup would be to have an insulated downrigger cable, with the last few feet near the ball having the insulation stripped off. This makes the positive field much bigger, and ensures that the field does not dissipate at all if you're fishing 100' deep. Of course, the biggest problem with this is putting the voltage on your cable at your boat... you can't use the normal American Black Box or Scotty-style voltage pickups that the cable runs through, because the cable is now insulated... I tried to overcome this problem by machining a rotary pickup that fit inside the lid of my Scotty electric, but I lacked the time to really mess with it, and also, I couldn't find a source of thin insulated wire. I found some commercial downrigger wire that was insulated, but it had a thick insulated coating that made the cable too thick overall, and even with a 15lb. downrigger ball, it had too much drag in the water. I guess the commercial guys used 60lb balls, so it didn't matter to them. If anyone knows a source of some stainless wire 130lb-150lb test with a tough, thin, electrically insulated coating (maybe Kevlar?) let me know, email me if you like.

I've got the "American Black Box", I bought it a few years ago, at the time, the Scotty's didn't pulse their voltage, and the American did. Ollie Rod talked about how important the pulsing was, as it mimics the panics of baitfish being fed upon, so I bought the American. It looks different than the Scotty, it's got an analog meter. I don't think I'd fish without it anymore.

I agree, when the fishing is good (like this year at Sekiu) I don't think you need it, but there were many days in the past few years fishing the Seattle area when our boat was catching a few fish and most everone else wasn't catching any.

I think some fish are more succeptable to this "positive attraction" than others. I think sockeye are super attracted by this, they are gear hounds as it is, and yes, these boxes work in fresh water, just not as well... last year in the Lake Washington sockeye fishery, my friend and I would troll next to each other in formation, put as much gear down as we both could, and turn both our black boxes on, many mornings our boats were limited before other guys had two fish, once we got in a school, I think the school followed us around.

I've watched coho swim right behind my downrigger cable before, just about three feet back and two feet deep... made me think that if you have your voltage dialed in, you might want to fish closer to your rigger cables than normal.

Most important thing for you guys without black boxes to remember is to tune your boat, and make sure you're not giving off a negative charge. You can do this by adding or subtracting zincs. If you can get your boat to read somewhere from 0.4V+ to 0.7V+, you're golden. (remember, some say bigger fish like lower voltages, like .45V+ for big kings... I haven't been able to confirm this for sure.) Eliminate any stray voltages, make sure everything is grounded properly, and if you're using downriggers, make sure your downrigger cables are insulated from your boat hull (they normally are) Also, when you're out there trying to take your voltage readings, don't try to do it in the marina or around other boats, their stray voltages can throw off your reading. Just go fishing, and a couple of times that day, while your gear's in the water, put your negative probe on your battery terminal, and your positive probe on your downrigger cable.

Now I've got one question for you "electrically concious" fishermen... I'm curious as to whether you guys prefer to insulate your downrigger balls from your cable (with a snubber, plastic clip, etc) or if you use balls dipped in rubber (as to give off no negative ions) or, if you have a black box, does it matter, and can you use a metal clip and electrically bond the ball to the cable, thereby making the ball a part of the positive system? (or would this bring the overall voltage down?) Just curious what you guys think.

-N.

[ 10-07-2001: Message edited by: StorminN ]

[fishineer]

Pilar,
In your circuit diagram, it looks like the diode is shown backwards. To get the 0.6 volts you want, you want to forward bias the diode. To forward bias the diode, you want the positive supply on the anode and the negative supply (or ground) on the cathode. For the diode symbol, the straight line portion is the cathode and the triangular shape of the symbol is the anode. So, I think if you flipped the symbol in your diagram the polarities should be right. Also, as you pointed out, on the physical diode, the end with the marking (usually painted or marked with a line around the body of the diode) is the cathode.
Thanks for the interesting post.
Dave

[Pilar]

Wrong!

How did I get through school?

[ 10-09-2001: Message edited by: Pilar ]

[Pilar]

SSHHEEAAATTT!!

You don't go to the proctologist to have your foot removed from your mouth. If you want solid state circuit design dont go to an EE (me) that writes computer code.

Fishineer is right! I crawled under the dashboard of 'Pilar' last night and the damn diode is pointing the other way!! Sorry buddy, thanks for being persistant. I just built it down in the shop and I've got it crossed up.

If you are building this contraption make sure the diode points the opposite way from what I showed in my sketch.

I'll edit that post with the correction. Fishineer, the beer is on me.

BTW what is the correct seasoning for raisin pie?

[Jeffhead]

Yes,
I use the plastic coated balls and isolate them by using parachute cord to attach them to the clip on the rigger' wire. Uncoated ones create thier own electrical field.
Good luck and tight lines, Jeff [img]images/icons/grin.gif[/img] [img]images/icons/grin.gif[/img]

[Pilar]

Hmmmm. never thought about it before. All of the downrigger balls I've bought are plastic coated. I just clip the downrigger wire terminator to the ball and go.

Jeffhead is right about the bare lead ball. Any dissimilar metals( lead, stainless ) in an electrolyte ( seawater ), make a battery. This will result in stray electric fields.

One thing is for sure, there is a lot more to know about this whole subject. Or maybe the fishing is slow and we are bored.

[StorminN]

OK, guys, what do you think about downrigger balls? Should they be insulated from the cable, should they be covered in rubber, whaddya think??

-N.