ground n. 12. 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. West Marine is committed to outfitting your life on the water. Generally, anodes should be replaced when 50% or more depleted. Figure 4. Also, the motor, … 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. Never use the mast, engine, or other metal object as part of the return circuit. See Figure 3. Knowing that bonding system is working is good for peace of mind and more: Your boat will thank you with better performance and improved reliability. There is no chance that you can dissipate the charge between the ocean and the atmosphere, so don't bother with a static dissipater at the masthead. A few requirements must be met for a bonding system to work. Ground fault circuit interrupters (GFCI) should be installed in each AC circuit. Your stainless steel propeller shaft will be protected from itself, by the same shaft zinc that protects the propeller from the stainless steel shaft. Therefore, the utmost care must be taken to ensure these systems remain in good working order. Interconnection of these underwater metals protects against stray-current and galvanic corrosion. Having said that, the misunderstanding is not surprising: Bonding systems are covered by two ABYC standards, E-2 Cathodic Protection and E-11 AC and DC Electrical Systems, which have different goals, corrosion mitigation and electrocution/fire prevention, respectively. By Think of it as plating, but in reverse: electricity is being used to remove metal. Like any other critical component, bonding systems should be inspected regularly. If you feel like spending real money on galvanic isolation, you might as well do it right and buy an isolation transformer. Make sure that this is the case. There is a very good reason for this confusion as the requirements surrounding bonding conflict. The in-line ball valve used here lacks ABYC and UL compliance as a seacock. Your zinc is incapable of supplying enough galvanic potential to protect against substantial DC currents that may be flowing in the water. Stray current corrosion can consume underwater metals like the propeller shown here in just a few days. These capacitors will be transparent to the RF, which will be happily grounded by the ground tape system, but they will block any DC currents from running through the RF ground system, and will avoid any resulting susceptibility to hot marina electrolytic corrosion. So how do we keep the keel or ground plate electrically isolated as required in "Bonding and Electrolytic Corrosion..." above? The DC load returns of all branch circuits should be tied to the negative bus of the DC distribution panel. Use zincs to protect against the galvanic currents that are set up by dissimilar metals on your boat that are immersed and that are in electric contact with one another. Figure 2. Unfortunately, these units cost substantially more than conventional Galvanic Isolators. Galvanic corrosion problems as a result of bonding the AC system to the hull When plugged into shorepower, and the AC system ground is bonded to the hull, the quayside, other boats and your boat creates a battery which, 9 times out of ten, causes a current to … Thirdly -- a major point here -- the AC power system on the boat (green wire) is also grounded to the boat’s common ground point, usually established at the engines. 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. 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. 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. Your zinc is only intended to protect against the modest galvanic potentials and therefore currents that are caused by the dissimilar metals that are immersed and electrically connected together on your own boat. Keep your metal keel/ballast electrically isolated from all other bits of metal. Certain Galvanic Isolators (e.g. In addition to the AC ground, we need a DC ground or return line, a lightning ground, and a RF ground plane for the radio systems. Well, the EPA has us back to copper again, only this time cupric oxides are the toxic agent. 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. Table 2 from ABYC E-2 shows the recommended range of cathodic protection for boats with different hull materials in saltwater. It works even better as a telltale for … See figure one. The boat's electrical system should be connected to seawater at one point only, via the engine negative terminal or its bus. Bonding System: The boats bondingsystem is basically a “Daisy Chain” of wires and cables. 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. Every light or appliance should be wired with its own DC return wire. I’m installing a bonding system on my boat. The electrochemistry of this assertion is compelling enough to recommend that you protect a stainless steel rudder shaft with a zinc. There should never be any current in the bonding system. The unintended DC connection between mast and DC ground is typically made by the masthead VHF whip, which connects the shield of the coax to the bracket connected to the mast. When the anode is depleted to the point where it’s unable to maintain the aluminum at a voltage more negative than its freely corroding potential, the aluminum will begin to corrode in spite of the presence of an anode. When installing or augmenting bonding systems, connections should be made using heat shrink terminals, and conductant paste such as Thomas & Betts Kopr-Shield. 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. It appeared in the October 15, 1996 issue of Practical Sailor magazine. Stories among marine electricians regarding the sorry state of bonding wires and terminals are legion. As outlined above, it is avoidable trouble. 41 WoodenBoat Lane Once the DC connection from the mast to the VHF is broken, check for any other connections with an ohmmeter, and straighten out any other wiring errors or unintended connections. It consists of the green grounding wire in the AC wiring system and serves the purpose of preventing shocks or electrocution. 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. In the old days, the technique of bonding everything together worked okay. Unfortunately, a connection between any of these systems and underwater metal can, and probably will, give rise to serious electrolytic corrosion problems. 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. Figure 1. The commercial units look like a coax "barrel" connector. Deadheads, sleeping leviathans, wayward shipping containers, maybe a disabled autonomous surface vessel, or a drifting wreck: countless unknown (and unseen) floating objects (also referred to as UFOs) that populate the… Read more », Humble hose clamps are essential to the integrity of hulls and onboard systems, but their reliability depends on informed selection and best installation practices. Honey is a highly decorated competitive sailor with a sublime record as an ocean navigator. This means that your boat’s common grounding and bonding system is electrically connected with the dock’s grounding system. One square foot is recommended for use in salt water; fresh water requires much more. Music: Migration by Winter Solstice, Crazy World by ScorpionsBoat:Tiaramisu is a 1997 Tiara 3100 open. Connect one end of the wire to a bonding ground source on your boat, like a rail or motor-mount bolt. The bonding system adds complexity to the boat, but can save many headaches, much expense and even heartache for the boat owner if it is intact when needed. The ground connection is usually made by clamping to a metal water pipe or by driving a long copper stake into the ground. The best solution is a heavy and expensive isolation transformer. The anodic bit of metal or thru-hull that has the misfortune to be on the "out current" side of the current running through your bonding system will also become "out metal" and will disappear, sometimes rapidly. This often represents a tall order as bonding systems live a harsh life, near and often in bilge water. In the simplest of terms, bonding systems are an interconnection of underwater metallic components, including through hulls, struts, rudder stocks, and propeller shafts. If your steaming light, masthead light, tricolor, Windex light etc. It should, therefore, come as no surprise that it does not include a dedicated bonding fastener. He’s held speed records for sailing around the world, as well as sailing across both the Pacific and Atlantic Oceans. Sintered bronze ground plates (e.g. Mount your automatic tuner as close to the backstay as possible, preferably just under the after deck. 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. Conductors running from the external keel or ground plate to the mast, stays and to the metal fuel tank will protect against a lighting strike, and there will be no DC connections to the engine or to the electrical system. Protected metals must reside in the same “body of water” as the anode. Stainless steel is a special case. A wiring diagram is a streamlined standard photographic representation of an electrical circuit. Given that you have grounded your mast solidly to the ocean, your mast will be at exactly the same electric potential as the ocean. This underwater metal will be grounded by connection to the seawater will serve as our water pipe. A bonding system provides an alternative path back to the power source that doesn’t travel through the water, thereby reducing, although not necessarily eliminating, the destructiveness of this type of corrosion. 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. To put it simply,the engine is connected to the inner gimb… It does not need to conduct DC, and as described in "Bonding and Electrolytic Corrosion..." above, you do not want to connect another DC ground to your engine and to your keel etc. This is done because of the galvanism caused by the different metals. If stray current corrosion is the hare, galvanic corrosion is the tortoise, taking months and years to do its dirty work. Completed connections should be coated with corrosion inhibitor such as CRC Heavy Duty Corrosion Inhibitor. Your VHF doesn't need to use the ocean as a counterpoise, so here we are dealing only with the ground needed for your HF/SSB radio. While this interconnection method works well, it has limitations. The solution is to find a dry secure place along each of the copper RF ground tapes that are running to your engine and keel. Fax: 207–359–8920. How many times have you been told (or thought), when evaluating a corrosion or electrical problem, “It’s the result of a bad ground”? The simple answer to this is to “break” the shore to boat earth by fitting a galvanic isolator or an isolation transformer immediately before the hull bonding … Bonding systems also mitigate galvanic or dissimilar metal corrosion, which occurs when dissimilar metals are in contact with each other, either directly or via wires, and immersed in an electrolyte (seawater in these cases), establishing a galvanic cell or battery. Run copper ground tape from the tuner to the stern pulpit/lifelines, to the engine, and to a keel bolt. Perhaps the most misunderstood case involves anodes found within the cooling systems of engines, generators, and other heat exchangers. Quicksilver) include large capacitors in parallel with the isolation diodes, which in certain situations theoretically provide better galvanic protection. Once again, it’s similar to plating in reverse, albeit at a glacial pace. Box 78 These DC currents in the water will cause electrolytic corrosion to your bonded thru-hulls or metal parts. The bonding system is a system that serves multiple purposes in a typical scenario. Think for a moment about this… Read more », Quirky marine toilets are a reliable source of wonder and potty humor during onboard cocktail banter, but they’re a lot less amusing if you’re the master, mate, or mechanic charged… Read more », Professional BoatBuilder is written and edited for boat builders, repairers, designers, and surveyors. As an ocean navigator bond any thru-hulls or metal parts writing a on! In both cases the pits, if you have them, 2019 by Larry A. Wellborn of! Current corrosion can bonding system on a boat occur even if there is some anode left, a frequent occurrence with sterndrives instance! Both the Pacific Transpac Race Windex light etc worth selecting the capacitors carefully, because they may a... 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