Trolling Wire Voltage Drop

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Seafoam
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Trolling Wire Voltage Drop

Post by Seafoam »

I have a Russell Electronics black box on my 50 foot steel power troller. I use the black box mostly to monitor my natural voltage. I've noticed lately (in the winter when I'm not catching many kings and I obsess over this stuff) that my trolling wire voltage gets lower when I increase engine rpm's. For example, I'm trolling along at 600rpm and my wire voltage is at 0.680 volts. Now it starts getting shallow and I'm going over a pinnacle. I rev the engine up to 900rpm and the black box shows the wire voltage gradually dropping to 0.640 volts. The voltage stays there until I slow down to 600rpm, then the voltage gradually comes back up and settles at 0.680 volts again. Anyone else ever notice this? It's not much of a difference but it doesn't seem to me that it should happen at all unless I have a short circuit somewhere.

I've tried dialing in the voltage on my black box, but the best fishing I've ever had were on days when I forgot to turn it on. So I just use it to monitor my voltage now. I would appreciate any input from you on this mysterious subject. Thanks.
Trnaround
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Re: Trolling Wire Voltage Drop

Post by Trnaround »

Sounds like you are putting out voltage from your alternator somewhere. Maybe a short to your ground.
Not good.
Trnaround
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Re: Trolling Wire Voltage Drop

Post by Trnaround »

Does it happen if you take it out of gear and rev the engine without changing the boat speed? That small amount of change in voltage could be from less wire in contact with the water when you speed up. I am no expert but If it still fluctuates when you rev it out of gear it seems like it would point to an electrical problem.
Seafoam
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Re: Trolling Wire Voltage Drop

Post by Seafoam »

Thanks for the suggestion. I'm heading back out tomorrow and I'll try checking the trolling wire voltage while I rev up the engine out of gear. Maybe you're right, less trolling wire in the water would make less voltage. I'll post the results here. Meanwhile, I'll keep looking for a short circuit. Hundreds of wires on this boat, driving me nuts! I've tried turning off all the breaker switches on the switch panel while trolling, didn't make any difference. Trolling wire beads and floatbag hardware turn pink after being in the water for a while. Could this indicate a short too?
Homeshore
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Re: Trolling Wire Voltage Drop

Post by Homeshore »

The drop in voltage may have something to do with the speed of the seawater going past the wire and your hull & prop.
Certain Ford cars had issues with severe electrolysis eating holes in the heater core. One of the fixes (from Ford Motor Co) was putting a restrictor in the heater hose to slow down the coolant flow.

Part of the diagnostic process was hooking the volt meter to ground, and placing the positive lead in coolant while revving the engine.
Problem vehicles would produce over .4v with the engine revved up.

The voltage produced by your trolling wire vs the voltage produced by your prop and hull must change with different speeds through the water.

Just a guess.
curmudgeon
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Re: Trolling Wire Voltage Drop

Post by curmudgeon »

I'm wondering if your gurdies, blocks, etc are well isolated. Maybe something metal making a bridge to your troll-wire, or from your hydraulics to the valves? From your hayrack to the gurdy spools? When you say that the wire stops are turning pink it makes me think poor isolation.
Your leads are separated from the wire by halibut gangion or something non-conductive, yes?
Was talking to another old timer who parks in the slip opposite mine and he told me about a trip he made with his brother right after they'd done a huge bunch of work to the boat and the trolling wire stops would start to fall apart after just a few days. He said they doubled the catch of the other boats around but it was sure hard on the wire! The fix was to bond everything metal on the hull and make sure the zincs were good. With your steel boat, bonding isn't an issue!
I have the same experience you do with the Black Box. Doesn't seem to make much difference if it's turned on or not. Use it to monitor voltage and play with it once and a while when it's slow. Never noticed a difference in catch rate. Have noticed that fish are a lot crazier at the surface if the voltage is much higher than .70 or so.
Seafoam
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Re: Trolling Wire Voltage Drop

Post by Seafoam »

Thanks for the comments and ideas. Homeshore, interesting about the electrolysis in the Fords because of coolant velocity, and I will check my wire voltage next time at different rpms without increasing my boat speed. Curmudgeon, I've been careful to isolate my gurdies, they are mounted up off the deck on insulators and non-conducting pads. There are non-conducting hydraulic hoses going to them. The trolling blocks are nylon and I have gangions connecting the cannonballs to the trolling wire. I have a lot of zinc below the waterline and I dove under the boat recently to check them and scrub them with a stainless brush. I'm really puzzled about the beads and the floatbag hardware turning pink and degrading after a couple of hours in the water, even though the black box is showing only 0.68 volts. It hasn't always done that. I wonder if it indicates a hot wire grounding out somewhere. I spent all day today re-doing electrical terminals, pulling out unused wires and looking for worn insulation or bad connections. Going to get my gear back in the water tomorrow or Tuesday and try it all again. I am happy to hear from all who commented here and I welcome more thoughts, ideas and suggestions. I will post here again when I have some more news on this subject. Sometimes I think this black box is like voodoo or black magic, it only works if you believe!
Trnaround
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Re: Trolling Wire Voltage Drop

Post by Trnaround »

A thought on the pink discoloration, have you been grinding metal or paint near your gurdies? Is there a chance of another metal contaminating your gear? Neighbor grinding? Sometimes haul out yards have some interesting dust in the air.
Salty
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Re: Trolling Wire Voltage Drop

Post by Salty »

I have not used gangions in about 20 years. Absorb salt, wear, break. I use spectra now. Doesn't absorb salt, doesn't break, doesn't wear.
Seafoam
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Re: Trolling Wire Voltage Drop

Post by Seafoam »

Just back from my latest shakedown trip. Trnaround and Homeshore were on the right track. My trolling wire voltage was dropping when I increased rpms because of the increase in speed through the water. I tested this by trolling downwind. taking the boat out of gear, and revving up the engine. When I did this there was no change in trolling wire voltage. Then I deliberately sped the boat up and the voltage would drop proportionately with the increase in speed. This happened every time I tested it, and by the same amount. When I first noticed this I was worried that the drop in voltage indicated a short somewhere: now I can find something else to worry about.

The discoloration and electrolysis of my floatbag hardware and trolling wire beads was unrelated. I solved that problem but I'm not sure how. I re-did all the battery terminals by disconnecting them and brushing them all with a wire brush and sandpaper. I replaced a solenoid that was acting up. I tightened all the terminal screws on the breaker switches in the switch panel. Went all over the boat with a screwdriver and tightened any electrical connections I could find. I removed a bunch of un-used wires that were no longer connected to anything. I replaced the breaking strap gangions on my cannonballs. I don't know which of these tasks made the difference, but after 4 days of trolling I didn't see any discoloration or degradation of my trolling gear. Did the boat fish better? I don't know, there weren't many fish around, and I was catching about the same amount as a friend who was fishing nearby. At least it helped my confidence. Now I will concentrate on finding the fish and quit fretting about voltage. Thanks to all who added to this thread.
Trnaround
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Re: Trolling Wire Voltage Drop

Post by Trnaround »

Seafoam, that is good that you don't have electrical problems and the good news is your box is working properly. Whether it helps you catch fish is the other question. I turn mine on every time we go fishing when I remember so I won't have to blame not having it on for my not catching fish. I am always confused when I discover it isn't on and we are catching but I turn it on right away so that I won't have missed opportunities from not having it on. That keeps me from driving myself crazy not at all related to catching fish. Good fishing.
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