you need its strength), then you should connect a nearby, immersed zinc to it; this protects the stainless steel from itself, reducing the rate of pitting. 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. 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. 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. But zinc only protects metal that is part of what’s called a bonding system—a network of wires that interconnects rudders, shafts, trim tabs, and struts, as well as interior components, to a transom zinc or zincs. When an anode is connected to the bonding system it becomes the least noble metal in the electrical chain and thus sacrifices itself. It is also a good idea to use a Ground Fault Circuit Interrupter (GFCI) in your AC wiring. Bonding System: The boats bondingsystem is basically a “Daisy Chain” of wires and cables. In both cases the pits, if they appear, will appear where the stainless steel is not exposed to the water. 41 WoodenBoat Lane This RF device puts a capacitor in series with the center conductor, and another capacitor in series with the shield. He is the technical editor of Professional BoatBuilder, and is writing a book on marine systems, to be published by McGraw-Hill/International Marine. Drop the silver chloride electrode into the water, attach the positive electrode to the DC bonding system or the underwater metal to be protected, and check the voltage. It is also the connecting system for the boat's grounding system. This is done because of the galvanism caused by the different metals. 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. 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. 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. 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. Start with the master battery switches, if you have them. This underwater metal will be grounded by connection to the seawater will serve as our water pipe. The battery negative is also connected to the engine negative terminal or its bus. 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. This often neglected system is what is supposed to keep all of the underwater metal components at the same electrical potential. 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. These anodes are sized and designed to protect only these components. If dissimilar metals corrode when connected, then why, you might ask, is it beneficial to connect them via a bonding system? The bonding system green wire has nothing to do with the 120v or 12v electrical system, and therefore no electrical equipment should ever be grounded to the bonding system. Box 78 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. Stories among marine electricians regarding the sorry state of bonding wires and terminals are legion. 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. 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. © 2021 Professional BoatBuilder Magazine. An internal bonding circuit connects the major metal objects on a boat to the grounding plate via bonding cables. The maximum allowable resistance between anodes and bonded components is a scant 1 ohm. 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. 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. Never use the mast, engine, or other metal object as part of the return circuit. Trouble areas are in the cutlass bearing, inside the rudder bearing, and just inside the top of the rudder. A properly bonded and isolated system should not require zinc changes more often than 6 to 8 months at a public marina. Honey is a highly decorated competitive sailor with a sublime record as an ocean navigator. ground n. 12. You can use a socket wrench to remove a bolt on the engine and place the wire there. Bonding: A separate system electrically connecting all metal fittings on the boat that are in contact with the water, including the sacrificial anode (s), and connecting them to the earth ground, so they are all at the same voltage potential, zero. 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. Have each of the cables that are used for lightning ground wires lead as directly as possible to the same keel bolt, with any necessary bends being smooth and gradual. Figure 1. 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. The electrochemistry of this assertion is compelling enough to recommend that you protect a stainless steel rudder shaft with a zinc. Brooklin, Maine 04616 USA Wire "bottle brush" static dissipaters may be useful to dissipate seagulls, however, but that is beyond the scope of this article. In those cases, the shaft brush provides a link to the vessel’s bonding system and the anodes to which it is connected, the advantages of which will be explained below. The key factor here is that the yacht's electrical system is connected to seawater ground at one point only, via the engine negative terminal or its bus. It stopped marine growth cold, but it turned the entire bottom of the boat into a bonding system. There should never be any current in the bonding system. The in-line ball valve used here lacks ABYC and UL compliance as a seacock. Well, the EPA has us back to copper again, only this time cupric oxides are the toxic agent. Also, the motor, … One school of thought suggests that if you must use stainless steel underwater (e.g. This device is transparent to the VHF RF signals in the center conductor and shield, but blocks any DC current in either the center conductor or shield. The easiest solution is to insert what is called a "inner-outer DC block" into the coax. Furthermore the bonding of equipment will make paths available for fault currents to allow protection devices or detection devices to react. 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. The various systems, DC negative, AC safety ground, and the bonding system are typically, and in order to be ABYC compliant, connected as one. 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. Figure 3. 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. They used #8 wire for the system and did a nice and tidy job of it. 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. 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. In the simplest of terms, bonding systems are an interconnection of underwater metallic components, including through hulls, struts, rudder stocks, and propeller shafts. On a boat, things are considerably more complicated. Definition: Bonding noun 1: fastening firmly together [syn: soldering] Overview. On ships most equipment will be installed directly onto metallic floors or bulkheads that are part of the vessel’s structure and are as such bonded together. Make sure that this is the case. Certain Galvanic Isolators (e.g. Shaft brushes are specifically designed to maintain electrical contact with a rotating surface. That confusion can also extend to bonding wires, according to marine surveyor Derek Rhymes, who wrote this response: Last year I encountered a situation where a well-known and respected boatyard had added a bonding system to a 42 (12.8m) motor yacht. Hose clamps and unterminated conductors are a poor means of making such connections. See figure one. Therefore, only machine screws should be used to complete bonding and other onboard electrical connections. If you feel like spending real money on galvanic isolation, you might as well do it right and buy an isolation transformer. For those of you not familiar with all of this, the bonding system on your boat is the green wire (most boats) you see in your bilge area that connects all the metal parts on your boat that are in contact with sea water. If the ballast, engine, and lifelines are available, however, they generally make a high performance ground. Bonding systems can reduce the corrosion potential of metals inside and on the bottom of the boat. 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. I’m installing a bonding system on my boat. It shows the components of the circuit as streamlined forms, and the power … Your stainless steel propeller shaft will be protected from itself, by the same shaft zinc that protects the propeller from the stainless steel shaft. By wiring them together, the differing potentials are equalized. I have a shaft tube and composite rudder bearing so all that was underwater was thru hulls and my stainless exhaust tip. Table 2 from ABYC E-2 shows the recommended range of cathodic protection for boats with different hull materials in saltwater. It is good practice to include the HF/SSB radio itself in this network of ground tapes. Turn off every electrical device on the boat. Like any other critical component, bonding systems should be inspected regularly. Don't bother with the backstay if it is interrupted with antenna insulators. This often represents a tall order as bonding systems live a harsh life, near and often in bilge water. We’ve found the information contained in his article still pertains today when grounding your electrical wiring on board your boat. A wiring diagram is a streamlined standard photographic representation of an electrical circuit. Note that this meets the ABYC recommendation. 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.". What parts need to be bonded? Fasten the tape securely to an insulating piece of phenolic or to a terminal strip, cut a 1/10-inch gap across the tape, and solder several 0.15uF ceramic capacitors across the gap. 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 … Music: Migration by Winter Solstice, Crazy World by ScorpionsBoat:Tiaramisu is a 1997 Tiara 3100 open. November 9, 2019 by Larry A. Wellborn Variety of boat bonding wiring diagram. Your zinc is incapable of supplying enough galvanic potential to protect against substantial DC currents that may be flowing in the water. 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. 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. Because of its close proximity to bilges, bonding system wiring lives a harsh existence. Sintered bronze ground plates (e.g. 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. It is worth selecting the capacitors carefully, because they may carry a significant amount of RF current. 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. 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. While the terms are used interchangeably, there are differences between grounding and bonding systems and their requirements and goals. They cannot protect underwater metals and, more importantly, hull anodes cannot protect gear filled with raw water within the vessel. Think of it as plating, but in reverse: electricity is being used to remove metal. For the sake of this article, however, I’ll stick to corrosion mitigation and use the term, bonding system (all of the following applies to fiberglass composite hulls). Testing for proper continuity and bonding is simple in concept but tedious. 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. This should also be true of your masthead instruments. Interconnection of these underwater metals protects against stray-current and galvanic corrosion. Bonding is a topic for another entry here and i'll certainly get to it at a later date. Quicksilver) include large capacitors in parallel with the isolation diodes, which in certain situations theoretically provide better galvanic protection. Do not rely on a thru-hull or a sintered bronze radio ground (e.g. Dynaplate) for use as a lightning ground. Run copper ground tape from the tuner to the stern pulpit/lifelines, to the engine, and to a keel bolt. Leave lead keels/ballast isolated. So how do we keep the keel or ground plate electrically isolated as required in "Bonding and Electrolytic Corrosion..." above? Stray current corrosion can consume underwater metals like the propeller shown here in just a few days. Mount your automatic tuner as close to the backstay as possible, preferably just under the after deck. The commercial units look like a coax "barrel" connector. Connect one end of the wire to a bonding ground source on your boat, like a rail or motor-mount bolt. Specifically, keep your metal keel/ballast, your metal rudder shaft, your engine/prop, and all thru-hulls electrically isolated, from each other, and from the engine. They provide a path for ground-fault currents, prevent touch-voltages on metal surfaces and provide a path for stray currents. Coat with corrosion inhibitor when complete. In an increasing number of marinas, there are substantial DC electric currents running through the water. Just to keep it interesting, there’s also a considerable degree of overlap. Completed connections should be coated with corrosion inhibitor such as CRC Heavy Duty Corrosion Inhibitor. It's worth understanding the reason. So how can you be sure your bonding system is really working? Last Updated: 8/5/2019The following article was written by renowned sailor and electrical engineer Stan Honey. Our first thought might be to simply make the ground connection to a metal thru-hull, propeller shaft or other underwater metal. Every metal item on the boat produces or contains a voltage since it is connected to water through props and zincs. Buy an isolation transformer in seeking a return path to its source it can be extremely destructive ; current... Them together, the EPA has us back to copper again, only machine should... 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