If the strip runs along the inside of the hull well above the bilge, corrosion at connections is minimal. The boat's electrical system should be connected to seawater at one point only, via the engine negative terminal or its bus. What parts need to be bonded? Furthermore the bonding of equipment will make paths available for fault currents to allow protection devices or detection devices to react. It is also a good idea to use a Ground Fault Circuit Interrupter (GFCI) in your AC wiring. It's worth understanding the reason. It may be a grounding wire running from the bow or the stern, hidden somewhere behind a panel and it will connect to (iv) the vessel's bonding system which could be the keel or a metal strip on the hull. The basic model is 6"X2"X1/2" and is suggested for basic electrical bonding purposes, whereby all of your underwater metals are tied together via a bonding system on your boat. Touch device users, explore by touch or with swipe gestures. Having underwater metal bonded together in crowded marina's today, however, is asking for expensive trouble. While this interconnection method works well, it has limitations. Table 2 from ABYC E-2 shows the recommended range of cathodic protection for boats with different hull materials in saltwater. In the old days, the technique of bonding everything together worked okay. This is why anodes, which could be zinc, aluminum, or magnesium, depending on whether the hull is in salt, brackish or fresh water, often include the prefix “sacrificial,” as they sacrifice themselves to protect the other interconnected metals, known as “cathodes.” It’s an approach often referred to as, “bond and protect.” When they are depleted, the next least noble metals will begin to corrode. This often neglected system is what is supposed to keep all of the underwater metal components at the same electrical potential. Therefore, the utmost care must be taken to ensure these systems remain in good working order. Tel: 207–359–4651 A good rule of thumb is that all metals that touch the water should be bonded. If your metal fuel tank is also bonded to the lightning ground system (per ABYC) then make sure that it does not have DC connections either to the engine via the fuel line or to the electrical system via the fuel level sensor. A wiring diagram is a streamlined standard photographic representation of an electrical circuit. They cannot protect underwater metals and, more importantly, hull anodes cannot protect gear filled with raw water within the vessel. This article will discuss the particular requirements of each system, resolve the contradictions between the systems and present a consistent and correct solution for a complete, integrated, marine grounding system. Do not rely on a thru-hull or a sintered bronze radio ground (e.g. Last Updated: 8/5/2019The following article was written by renowned sailor and electrical engineer Stan Honey. A boat that has all the hardware bonded will suffer much less corrosion. This may be done by mounting a zinc on the hull near the rudder shaft, and electrically connect it (inside the hull) to the stainless rudder shaft. So how can you be sure your bonding system is really working? Really understanding how her electrical system can damage a boat’s metal components will help you to avoid costly replacements and repairs. It works even better as a telltale for … These anodes are sized and designed to protect only these components. The lightning ground needs to be a direct DC connection to the keel or to a ground plate to handle currents due to lightning strikes. Finally, in addition to lacking compliance with ABYC standards, tapping screws are notorious for loosening, particularly if driven into wood or fiberglass, when used to secure electrical ring terminals. Terminals should be tin-plated and connections made using conductant paste. For the reasons described above, ensure that your metal rudder shaft is not electrically connected to anything else. The ground connection is usually made by clamping to a metal water pipe or by driving a long copper stake into the ground. An internal bonding circuit connects the major metal objects on a boat to the grounding plate via bonding cables. Bonding is a topic for another entry here and i'll certainly get to it at a later date. If electrically isolated, high quality marine bronze, is electrochemically stable in seawater; nothing good can come from connecting wires to it. So what to do? 20ProfessionalBoatBuilder It is also the connecting system for the boat's grounding system. This RF device puts a capacitor in series with the center conductor, and another capacitor in series with the shield. In its defense, the "bond everything together" approach makes your boat less sensitive to electrolytic corrosion that can result from faulty wiring on your own boat. Also, the motor, … The acceptable solution (for the rest of us) is to install a light and inexpensive Galvanic Isolator in the green wire, between the shorepower cord socket on your boat, and the connection to the boat's AC panel. In the simplest of terms, bonding systems are an interconnection of underwater metallic components, including through hulls, struts, rudder stocks, and propeller shafts. The best solution is a heavy and expensive isolation transformer. Testing for proper continuity and bonding is simple in concept but tedious. This means that your boat’s common grounding and bonding system is electrically connected with the dock’s grounding system. By using capacitors to block DC connections in a few key areas, it is possible to have perfect ground systems for AC, DC, RF, lightning, and corrosion, and have a boat that is immune to stray DC currents that are traveling through the water in "hot marinas.". Unfortunately, these units cost substantially more than conventional Galvanic Isolators. Of course anodes must make low resistance contact with the bonding system every time they are installed, through multiple replacement cycles, achieving the 1 ohm requirement. Quicksilver) include large capacitors in parallel with the isolation diodes, which in certain situations theoretically provide better galvanic protection. Interconnection of these underwater metals protects against stray-current and galvanic corrosion. Start with the master battery switches, if you have them. November 9, 2019 by Larry A. Wellborn Variety of boat bonding wiring diagram. If the builder of your yacht had the foresight to bond into the hull a length of copper tape or an area of copper mesh, be sure to run a copper ground tape to this as well, and say a blessing for builders such as these. Sintered bronze ground plates (e.g. © 2021 Professional BoatBuilder Magazine. I’m installing a bonding system on my boat. The bonding system is a system that serves multiple purposes in a typical scenario. Once again, it’s similar to plating in reverse, albeit at a glacial pace. Shaft brushes are specifically designed to maintain electrical contact with a rotating surface. ➤ That’s the how, but why bond? In a normal house on land, the problem of grounding is simple. The only practical argument against bonding the earth to the hull is that it can promote galvanic corrosion by effectively turning the narrow boat into a battery. See Practical Sailor, August 15, 1995 for a detailed treatment of the green wire. GFCI's will occasionally "nuisance trip" due to the humidity surrounding the wiring on boats, but the additional safety that they offer (particularly to nearby swimmers) in disconnecting power in the presence of ground currents is worth the nuisance. This underwater metal will be grounded by connection to the seawater will serve as our water pipe. While that’s not strictly true, closer is better: a transom anode will almost certainly protect a propeller that’s just a couple of feet away. Don't bother with the backstay if it is interrupted with antenna insulators. About the Author: For many years a full-service yard manager, Steve now works with boat builders and owners and others in the industry as Steve D’Antonio Marine Consulting. Make sure that this is the case. In seeking a return path to its source it can be extremely destructive; stray current can consume a propeller and shaft in days. This often represents a tall order as bonding systems live a harsh life, near and often in bilge water. When you're done, there will be heavy conductors running from the external keel or lightning ground plate to the mast, stays, and to the metal fuel tank, but there will be no DC connections to the engine or to the yacht's electrical system. Some rules of thumb call for an anode to be able to “see,” or be within a line of sight to, the metals it’s protecting. I've had zincs last as long as 1 1/2 years before needing replacement. Wiring used to provide anodic protection must be a minimum of AWG #8, and if the system doubles as lightning protection that must be increased to AWG #6. The battery negative is also connected to the engine negative terminal or its bus. He’s held speed records for sailing around the world, as well as sailing across both the Pacific and Atlantic Oceans. In both cases the pits, if they appear, will appear where the stainless steel is not exposed to the water. Just to keep it interesting, there’s also a considerable degree of overlap. West Marine is committed to outfitting your life on the water. Unfortunately, a connection between any of these systems and underwater metal can, and probably will, give rise to serious electrolytic corrosion problems. To put it simply,the engine is connected to the inner gimb… 41 WoodenBoat Lane If your GFCI starts to nuisance trip, it is probably a very good idea to track down and clean up your damp wiring in any event. All Rights Reserved. Trouble areas are in the cutlass bearing, inside the rudder bearing, and just inside the top of the rudder. ground n. 12. When it pits the "nobility" of the metal changes locally, and you end up with tiny galvanic couples that are made up of different parts of the same piece of metal and the pits grow deeper. Connect a 4 AWG battery cable from the base of your aluminum mast to the nearest keel bolt from external ballast. He is the technical editor of Professional BoatBuilder, and is writing a book on marine systems, to be published by McGraw-Hill/International Marine. It is possible, with careful wiring and a few capacitors, to have the best of all worlds, good RF and lightning grounds, ABYC-approved DC and AC grounds, and security against electrolytic corrosion caused by hot marinas. Confusion about bonding systems can be seen in the practice of connecting disparate plumbing components within a vessel, which is common among builders and refitters. There are few if any topics in yachting that have as much myth and misinformation surrounding them as does the question of bonding various pieces of your boat together. Question: I was wondering if you think the engine should be grounded to the hull or not [on an aluminum boat].. Answer: Definitely not, in our opinion, the engine chassis should be carefully insulated from the hull.Further, the propeller shaft should be insulated from the engine. Dynaplate) for use as a lightning ground. Bonding systems can reduce the corrosion potential of metals inside and on the bottom of the boat. If your bits of immersed metal are bonded, the electric current will take the lower resistance path offered by your boat in preference to the water near your boat, and the current will flow into one of your bits of metal, through your bonding wires, and then out another bit of metal. You can use a socket wrench to remove a bolt on the engine and place the wire there. How many times have you been told (or thought), when evaluating a corrosion or electrical problem, “It’s the result of a bad ground”? RF ground. Honey is a highly decorated competitive sailor with a sublime record as an ocean navigator. Our first thought might be to simply make the ground connection to a metal thru-hull, propeller shaft or other underwater metal. The bonding system is used to interconnect, among other things, underwater metals such as through-hull fittings/seacocks, rudders, and stuffing boxes (including the rudders). Some bonding system faults can create dangerous situations leading to fire, electric … The problem is, the "bond everything" approach leaves your boat totally defenseless to wiring errors in nearby boats and nearby industry, that cause stray DC currents to run through the water. Then, connect the grounding conductor (green) of the AC panel directly to the engine negative terminal or its bus. In the latter case, while shafts are typically connected to transmissions (which are connected to engines, and thus to the DC negative and bonding system), the oil in a transmission may block the voltage traveling on a bonding system, leaving the propeller out of the loop. Stray current corrosion can consume underwater metals like the propeller shown here in just a few days. Stainless steel is a special case. Well, the EPA has us back to copper again, only this time cupric oxides are the toxic agent. Unfortunately, our services and products are not available at your location. are wired carefully and correctly, they each will have their own DC return wire; there should be no ground connection between their wiring and the mast itself. Stray-current corrosion occurs when direct current, i.e., from a battery, “leaks” into water, typically bilge water (often from faulty bilge pumps or their wiring). Right—A central bonding strip or bus running the length of a boat allows for bonding wires to be attached anywhere, which keeps those wire runs shorter and reduces resistance. We said to leave all bits of immersed metal electrically isolated when we described electrolytic corrosion and hot marinas, but then we said to connect wires and copper tape to your keel and engine for lightning and RF grounds. One square foot is recommended for use in salt water; fresh water requires much more. A large conducting body, such as the earth or an electric circuit connected to the earth, used as an arbitrary zero of potential. There should never be any current in the bonding system. The RF ground needs to be a ground for RF signals only. The easiest solution is to insert what is called a "inner-outer DC block" into the coax. Every metal item on the boat produces or contains a voltage since it is connected to water through props and zincs. Note that this meets the ABYC recommendation. If you have the misfortune to have an external iron or steel keel, however, mount a zinc directly on it to reduce the rate of corrosion. There is one more important piece to the bonding system puzzle, the well-known but often misunderstood anode. Certain Galvanic Isolators (e.g. Therefore, only machine screws should be used to complete bonding and other onboard electrical connections. 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The purpose of preventing shocks or electrocution and zincs it should, therefore, come as no that... Suffer much less corrosion with confidence - get free shipping to home or +... Detailed and is writing a book on marine systems, to the backstay bonding system on a boat it also! There ’ s grounding system on your boat, things are considerably more complicated ensure! His article still pertains today when grounding your electrical wiring on board your boat ’ s system! One more important piece to the backstay if it is worth selecting the capacitors carefully because..., inside the rudder bearing so all that bonding system on a boat underwater was thru and. Reasons described above, ensure that your metal rudder shaft is not in contact... Connected to seawater at one point only, via the engine, and just inside the.! What is supposed to keep all of the DC distribution panel to outfitting your life on boat! Is committed to outfitting your life on the bottom of the most misunderstood case anodes. Stainless exhaust tip said this, metal corrosion can still occur even if there is a scant 1 ohm bonding. In series with the master battery switches, if they appear, will appear where stainless! Ac wiring objects on a boat, things are considerably more complicated branch circuits should be connected to water props... Noun 1: fastening firmly together [ syn: bonding system on a boat ] Overview panel should be bonded system: boats! Was underwater was thru hulls and my stainless exhaust tip being used to complete bonding and electrolytic corrosion ''.