Scotty Black Box
https://scotty.com/wp-content/uploads/2015/12/Black-Box-Booklet.pdf
The Scotty Black Box - How & Why There has been much research into the concept of using electricity to catch fish. Commercial fishing vessels have been using Black Box technology for years and now recreational fishermen are tapping into this resource. The Black Box has proven to be very effective in trolling, mooching, jigging and more. The purpose of this publication is to explain why. Fish & Electricity Russian scientists first discovered that bony and cartilaginous fish respond to the presence of electricity in the water. Many species use electric signals to communicate, some repel predators with it and others use electricity to navigate. Salmon, among others, are attracted to a positive charge and repelled by a negative charge. By maintaining a steady and appropriate positive charge on your downrigger wire, it is possible to attract fish and keep them interested in your lures. The Black Box does this in both salt and fresh water. Electrolysis To understand the Black Box, one must first understand the principle of electrolysis. This process is also known as galvanic action. Metals are ranked according to how strongly they react with other metals. The lower they are on the galvanic scale (or the less "noble") the more strongly they react. When dissimilar metals are placed in an electrolytic solution, electricity flows between them (basically: a battery) and corrosion occurs. The difference in nobility, or ranking, of metals determines how much electricity will be generated. Zinc, which is very low in nobility, is used in sacrificial anodes on boats to prevent corrosion of metal parts because it will corrode long before other metals. The Black Box The electricity generated in electrolysis puts a natural charge on your vessel. When using a downrigger, the reaction between your wire and your zinc anodes will normally generate about .8 volts (in saltwater). This positive charge on your downrigger wire has been known to attract fish. However, fish are extremely sensitive to changes in this charge. The Black Box is designed to regulate and monitor that charge through a metal contact sleeve over the downrigger wire. It also has a pulse mode which can be used to trigger strikes during slow times. Electrons flow from the boat metals, typically the less noble zincs, across the electrolytic solution (fresh or saltwater) to the downrigger cable. They then migrate into the Black Box drawn by the red battery post (anode). The black post (cathode) donates electrons to power the Black Box and is connected by a bonding wire to all metal parts in contact with the electrolytic solution. Page 1 No. 1201 Black Box 20 foot Load Line & Connector Sleeve The downrigger cable maintains a fish-attracting positive electric potential because the Black Box draws electrons from the downrigger line faster than electrons are donated through the water from boat metals. D.C.Reid, BC Outdoors Sport Fishing, JuneAugust 2002. The charge from the zinc to the downrigger line runs negative to positive because stainless steel attracts and sheds electrons faster than water can transmit them from the boat's zinc. This creates a relative absence of electrons, or relative positive charge around the downrigger line. A sleeve over the downrigger wire is connected to a wire which runs to the Black Box. By altering the rate at which electrons are transmitted from the surface of the downrigger line to the Box, the Black Box modifies the charge around the entire length of the cable. The circuit is completed as electricity is attracted by the positive or red battery terminal, passes through the battery to the negative post whereupon one lead powers the black box and the other connects through the bonding wire to the engine or outdrive. At this point, the circle begins again with the electrons being attracted back toward the downrigger line. The Black Box is most effective when connected to all the downriggers on the boat, providing a uniform positive charge around the hull. Up to 6 downriggers can be connected to one Black Box. A short drop back leader length is recommended in order to keep the lure within the electric field. Longer drop back leader lengths tend to put the lure into the weaker part of the field. Leaders of 10-20 feet work well. Depth can also alter the effectiveness of the Black Box. You may need to increase the charge slightly on your Black Box to compensate for deeper fishing (100' or more). Do not forget to turn it back down when fishing nearer the surface. The Black Box is also very effective when drift fishing, as fish have longer to react to the positive voltage effect and it can attract fish from as much as 300 feet away. The Black Box has also been used successfully for ice fishing. A Black Box is effective on all types of boat hull, provided it is properly bonded and equipped with zinc anodes. Aluminum hulls actually act as the negative side of the electrolysis circuit, creating a wider electric field and attracting fish from a broader area. Some vessels may be so well bonded that the natural electrolysis is ideal. These boats may not benefit from the use of a Black Box. A Black Box draws very little power (about .1 amp at full load). It has no effect on other electronics on board. Natural Electrolysis "Natural" electrolysis occurs on most boats even without a Black Box. There are several factors which will affect your boat's electrical condition. Your downrigger spool and wire line should be insulated from the boat hull in order to allow natural electrolysis to occur. All models of Scotty downriggers are fully insulated.· The sacrificial zinc anodes on your boat should not be more than 50% dissolved. They should be clean and unpainted. If you trailer your boat often, you should Page 2 scrub your zincs with plastic scrubber or stainless steel brush to remove the film which develops. This film will reduce the effectiveness of your zincs drastically. ! Do not use a brush or scrubber made of any other metal as it will contaminate your zincs. ! Your downrigger weights should be pure lead, as impurities can produce a negative charge. ! Use a nylon snap to connect the downrigger cable to the downrigger weight or use a short piece of monofilament to insulate the weight from the wire. This breaks a harmful elelctrolysis field which might occur. ! Replace your downrigger cable at least every 2 years if it has been used often in saltwater, as the galvanic action will etch it over time. ! Do not use zincs on your downrigger wire. This may cause a negative voltage zone to occur. Controlling Electrolysis It is important to guard against the effects of electrolysis on your boat. Careful testing of your boats electrolysis condition will prevent corrosion damage and perhaps enhance your fishing results. Ideally, your boat should be set up so that the corrosion is controlled and dissipated in the sacrificial anodes. It is recommended to measure the levels of electrolysis around your boat to ensure proper protection. Here's how: Inspect the inside your hull. Look for a copper bonding wire running along the bottom of the hull, connecting all the underwater metal fittings-engine, fuel tanks, thru hulls, etc. Check that this wire is unbroken and has clean, tight connections. Check the connections with a voltmeter, by touching the positive lead to the fitting and the negative lead to the bonding wire. The meter should show a reading of .010 volts. Aluminum boats with an outboard should be properly electrically grounded to the metal hull or bonding strap. An electric start outboard should also be grounded (connect the negative terminal of the battery to the boat hull). Also test for continuity to the boat hull or bonding strap as well as the outboard motor. A #10 bonding wire should be installed from the negative terminal to the hull and to the outboard if there is no continuity. With the boat in the water, lower a downrigger wire into the water a few feet. Do this away from marinas or docks to avoid stray electrical currents. Now test the voltage on your downrigger wire. With your downrigger weight and wire in the water, turn off everything electrical on your boat. Turn the master connect battery switches off. Connect the negative lead from your volt meter to the negative battery terminal, the engine or to one of the bonded metal fittings on the hull. Connect the positive lead to your downrigger wire near the spool or along the arm. You should get a natural electrolysis reading of between .7 and .9 volts. If your reading is much outside this range, you have a problem. Turn each of the boat's electrical systems on one at a time, starting with the battery switches, then the bilge pump, engine and than each of the other electrical devices. If your natural electrolysis voltage reading changes by Fuel Tank Bonding Wire Water Intake Rudder & Prop Battery Engine Fuel Tank Page 3 more than .05 volts you have an electrical leakage problem or a problem in the negative battery circuit. If you have electric downriggers, be sure to turn them on as part of your checkout. To test them, you will have to lower them deeper and then hold your positive lead against the moving wire as it rewinds. Base Readings: If your electrolysis reading is too low (.1 to .5 volts), your zincs may need cleaning or replacing, or your boat may not have enough zinc. You should also check the bonding connections for improper bonding. If your reading is zero or negative, your downrigger may not be insulated from the hull, your zincs may need cleaning or replacing, there may be electrical leakage from a positive connection somewhere, or your hull may not be properly bonded. If your reading is too high (over 1 volt), your downrigger may not be insulated from the hull or your downrigger wire may have been replaced with something other than stainless steel (ie monel)
