I need you electricans to help diagnose my problem. I go through 2 prop shaft zincs every three months. At first I thought it was dock, but all my sailboat neighbors seem to not have the problem and we run similiar equipment, battery chargers and in the summer air conditioners The only other hint I can give you is when I am plugged into the dock, my VHF transmits with a hum which pretty much drowns out any voice I suspect I have a ground problem but do not know where to begin. Any ideas?
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Same Problem
John, I had (have) the same problem. Not sure if the problem has been corrected yet or not and would also like feedback from anyone with ideas. So far these are the things I have found and/or were recommended. First, the ground wires on the galvanic isolator were loose. This component is well hidden in my boat up behind the electrical panel and not easy to see without getting your head inside. Both AC ground wires were less than finger tight. Apparently since built (coming on three years). Second, I checked every ground connection I could find on the boat. Most were tight, but a few needed to be a bit tighter. Finally, talked with a boat electrician. He suggested that we turn the boat bow into the slip. We have been backing it in. He felt that getting the prop and other stuff farther out was a good idea. I also have a full isolation transformer for the boat and he suggested installing it. I will continue to check zincs on a more agressive schedule over the next number of months until we feel resolved about the issue. As an aside, there was a 356 sister ship next to me these past few years. It lost a strut (also backed in). Hope this helps a little. Dan Jonas (S/V Feije II)
John, I had (have) the same problem. Not sure if the problem has been corrected yet or not and would also like feedback from anyone with ideas. So far these are the things I have found and/or were recommended. First, the ground wires on the galvanic isolator were loose. This component is well hidden in my boat up behind the electrical panel and not easy to see without getting your head inside. Both AC ground wires were less than finger tight. Apparently since built (coming on three years). Second, I checked every ground connection I could find on the boat. Most were tight, but a few needed to be a bit tighter. Finally, talked with a boat electrician. He suggested that we turn the boat bow into the slip. We have been backing it in. He felt that getting the prop and other stuff farther out was a good idea. I also have a full isolation transformer for the boat and he suggested installing it. I will continue to check zincs on a more agressive schedule over the next number of months until we feel resolved about the issue. As an aside, there was a 356 sister ship next to me these past few years. It lost a strut (also backed in). Hope this helps a little. Dan Jonas (S/V Feije II)
Yes, you have a Ground Problem
Is the reverse polarity lamp glowing? If you don't find it, it will eat up thru hulls (If they are brass), props, shaft and everything metal that is in contact with the water. Go to your power panel and remove the ground connection and check with a sensitive voltmeter across the open. I expect that you will measure some voltage there. You really need a competent electronics man to find the leak. It is like looking for a needle in a haystack.
Is the reverse polarity lamp glowing? If you don't find it, it will eat up thru hulls (If they are brass), props, shaft and everything metal that is in contact with the water. Go to your power panel and remove the ground connection and check with a sensitive voltmeter across the open. I expect that you will measure some voltage there. You really need a competent electronics man to find the leak. It is like looking for a needle in a haystack.
Simple test
If you don't have one, get one of the yellow plug-in 3 light neon testors from a home supply store's electrical department (under $7) and plug it into one of your shore powered outlets. This simple test will quickly show if you have a polarity or grounding problem. Even if the reverse polarity light doesn't light on your panel, this will identify a grounding problem if it exists. I use it every time I plug into a marina's shore power just to be sure all's well.
If you don't have one, get one of the yellow plug-in 3 light neon testors from a home supply store's electrical department (under $7) and plug it into one of your shore powered outlets. This simple test will quickly show if you have a polarity or grounding problem. Even if the reverse polarity light doesn't light on your panel, this will identify a grounding problem if it exists. I use it every time I plug into a marina's shore power just to be sure all's well.
More information
Jim, Some more information would be useful. When you say, remove the ground at the power panel...are you talking about the ac or dc? And, is the probable leak an ac leak or dc leak. And, exactly what is a leak (electricity wise, I understand the other kind and want to avoid turning this into one of those)? In my case, the ac grounds were loose at the galvanic isolator. Is that a probable cause? My reverse polarity light has not been on. Dan Jonas
Jim, Some more information would be useful. When you say, remove the ground at the power panel...are you talking about the ac or dc? And, is the probable leak an ac leak or dc leak. And, exactly what is a leak (electricity wise, I understand the other kind and want to avoid turning this into one of those)? In my case, the ac grounds were loose at the galvanic isolator. Is that a probable cause? My reverse polarity light has not been on. Dan Jonas
Dan
The leak is in the A/C side I believe. The a/c neutral side should be at ground potential. If it isn't, then some of the a/c current will flow through the zincs into the water to complete the circuit. And this doesn't necessarily mean that your boat is causing the problem. A neigboring boat could have a higher resistence in their neutral return than going through your boats zincs. But I think that you will find current flowing through your zincs.
The leak is in the A/C side I believe. The a/c neutral side should be at ground potential. If it isn't, then some of the a/c current will flow through the zincs into the water to complete the circuit. And this doesn't necessarily mean that your boat is causing the problem. A neigboring boat could have a higher resistence in their neutral return than going through your boats zincs. But I think that you will find current flowing through your zincs.
Questions
Jim, If I understand what you are saying, there should be no voltage showing up on a meter set across an a/c neutral to ground. Would it also be valid to disconnect the ac from the panel and measure resistance in the neutral and ground clear back through the shore plug? I'm still having trouble understanding what I'm looking for. IS it a frayed wire? Bad Charger? Also, as stated before, the AC grounds were only setting on the galvanic isolator terminals, not even finger tight. Could this have been the problem? Don't mean to be a pest, but while a lot is written on the subject, not much in the way of examples are provided as to what to look for, or how to test an individual circuit, etc. Thanks, Dan Jonas (S/V Feije II)
Jim, If I understand what you are saying, there should be no voltage showing up on a meter set across an a/c neutral to ground. Would it also be valid to disconnect the ac from the panel and measure resistance in the neutral and ground clear back through the shore plug? I'm still having trouble understanding what I'm looking for. IS it a frayed wire? Bad Charger? Also, as stated before, the AC grounds were only setting on the galvanic isolator terminals, not even finger tight. Could this have been the problem? Don't mean to be a pest, but while a lot is written on the subject, not much in the way of examples are provided as to what to look for, or how to test an individual circuit, etc. Thanks, Dan Jonas (S/V Feije II)
Dan, Jim and John
Guys, One thing you can check at the electronics panel make sure all coneections are tight. One time I was checking wires and a few of the ground wires were loose and very warm (so I tightened them all AC and Dc so this may be something to check. John
Guys, One thing you can check at the electronics panel make sure all coneections are tight. One time I was checking wires and a few of the ground wires were loose and very warm (so I tightened them all AC and Dc so this may be something to check. John
Good Info
I called Hunter today about this problem and although I spoke with them they haven't given me any info to go on. You guys are full of good info, even though the problem is not solved yet I want to thank you for your inputs I am off to buy a tester as suggested by Dan Johnson. As for the location of the galvanic isolator as explained by Dan Jonas, could you please give me some more info as to where it is, I going to spend Saturday doing some trouble shooting as described herein. In response to Jim Rushing, as I sit here typing I cannot recall for certain if the reverse polarity lamp is glowing, but I have a feeling it might be very dimly, something else I will look into Saturday By the way, not that it matters but my hull is number 197. Well I have a wealth of info. I will keep monitoring for more input and Saturday I will explore all the possibilities mentioned thus far Does the hum in the radio add any other clue?
I called Hunter today about this problem and although I spoke with them they haven't given me any info to go on. You guys are full of good info, even though the problem is not solved yet I want to thank you for your inputs I am off to buy a tester as suggested by Dan Johnson. As for the location of the galvanic isolator as explained by Dan Jonas, could you please give me some more info as to where it is, I going to spend Saturday doing some trouble shooting as described herein. In response to Jim Rushing, as I sit here typing I cannot recall for certain if the reverse polarity lamp is glowing, but I have a feeling it might be very dimly, something else I will look into Saturday By the way, not that it matters but my hull is number 197. Well I have a wealth of info. I will keep monitoring for more input and Saturday I will explore all the possibilities mentioned thus far Does the hum in the radio add any other clue?
Location
John, I think the hum in the radio is coming from the charger. My recollection is it goes away with the charger off. The location of my galvanic isolator was inside the electrical panel and up and back towards the head bulkhead. I had to put my head inside the panel opening to see it and could just reach it with my hands. I'm suspecious about the charger/inverter too. My link 2000 shows a .2 amp discharge in battery #1 even with the charger in float. Maybe I have a problem in the charger that is also throwing off the voltage leak. Just not sure how to validate same. My next step may have to be a marine electrician, although it bugs me that something like this is so hard to trace. I have wired homes and commercial structures, have a pretty good understanding of electronics, and installed all the equipment in my first boat. On that one the electrical works correctly. By the way, I think our hull numbers are pretty close together. Dan Jonas (S/V Feije II)
John, I think the hum in the radio is coming from the charger. My recollection is it goes away with the charger off. The location of my galvanic isolator was inside the electrical panel and up and back towards the head bulkhead. I had to put my head inside the panel opening to see it and could just reach it with my hands. I'm suspecious about the charger/inverter too. My link 2000 shows a .2 amp discharge in battery #1 even with the charger in float. Maybe I have a problem in the charger that is also throwing off the voltage leak. Just not sure how to validate same. My next step may have to be a marine electrician, although it bugs me that something like this is so hard to trace. I have wired homes and commercial structures, have a pretty good understanding of electronics, and installed all the equipment in my first boat. On that one the electrical works correctly. By the way, I think our hull numbers are pretty close together. Dan Jonas (S/V Feije II)
Charger hum
I have same hum in my radio but when I shut the charger off the hum stop,I don't have a zinc problem,my zinc does last all season plus some on my 290. nick
I have same hum in my radio but when I shut the charger off the hum stop,I don't have a zinc problem,my zinc does last all season plus some on my 290. nick
356 zinc problems
Hi John, we're hull number 198! we also have the same problems, and all of the advice so far is good. the definitive test is to get a silver cell (WM sells them, about $70, I think, and use it with your meter to measure the potential between the water (you hang the cell over the side) and your neutral and ground any voltage over 0.10 volt means that there's a bad connection somewhere-you just have to keep trying different points until you find the bad connection. We actually had a Hunter factory rep on our boat and he said that we didn't have the isolator, they were missed on some boats! by the time he sent one to our dealer to be installed, I had found it, tucked behind the nav station in the corner between the nav and power panels high up. the wires were connected properly, and tight. However, the ground on the keel were loose. so a lot of stuff on the grounding plan was not connected. Also, several of the screws on the neutral and ground power buses on the breaker panel were stripped, and the wires were just flopping around! not just a galvanic issue, a fire/safety issue as well-Dan, those are the other places I'd look. you also can check across ground connections to make sure you don't have any resistence-if you do, take the connection apart, clean, and reassemble
Hi John, we're hull number 198! we also have the same problems, and all of the advice so far is good. the definitive test is to get a silver cell (WM sells them, about $70, I think, and use it with your meter to measure the potential between the water (you hang the cell over the side) and your neutral and ground any voltage over 0.10 volt means that there's a bad connection somewhere-you just have to keep trying different points until you find the bad connection. We actually had a Hunter factory rep on our boat and he said that we didn't have the isolator, they were missed on some boats! by the time he sent one to our dealer to be installed, I had found it, tucked behind the nav station in the corner between the nav and power panels high up. the wires were connected properly, and tight. However, the ground on the keel were loose. so a lot of stuff on the grounding plan was not connected. Also, several of the screws on the neutral and ground power buses on the breaker panel were stripped, and the wires were just flopping around! not just a galvanic issue, a fire/safety issue as well-Dan, those are the other places I'd look. you also can check across ground connections to make sure you don't have any resistence-if you do, take the connection apart, clean, and reassemble
Dan
I will try to answer your questions. Disconecting the a/c wires and trying to measure their resistance would be difficult at best. Because of the large currents flowing in the wires, it only takes a small resistance to cause a voltage drop. Your typicle VOM meter isn't that accurate when measuring resistance. Also, we are talking about milivolts difference in potential causing the zincs to dissolve. As I said, it may not be your boat that has the electrical problem, but one of your neighbors. Grounding problems can be a nightmare and then in radio high freq circuits you can run into ground loops. Electrons can do strange things.
I will try to answer your questions. Disconecting the a/c wires and trying to measure their resistance would be difficult at best. Because of the large currents flowing in the wires, it only takes a small resistance to cause a voltage drop. Your typicle VOM meter isn't that accurate when measuring resistance. Also, we are talking about milivolts difference in potential causing the zincs to dissolve. As I said, it may not be your boat that has the electrical problem, but one of your neighbors. Grounding problems can be a nightmare and then in radio high freq circuits you can run into ground loops. Electrons can do strange things.
Ground problem
Jim Rushing: If a boat has an isolation transformer in its AC system, then the neutral leg of the AC system should never be at EARTH ground potential The sole reason for having an isolation 1:1 transformer is to divorce the boat's AC system from the earth ground. If the system's neutral AC leg is at earth ground potential then the isolation transformer is not working. This is a safety feature. If someone grabs the hot side of an isolated system and grounds his other hand in the ocean, there should be no injury. All he/she did was to provide a reference for the hot side of the circuit.
Jim Rushing: If a boat has an isolation transformer in its AC system, then the neutral leg of the AC system should never be at EARTH ground potential The sole reason for having an isolation 1:1 transformer is to divorce the boat's AC system from the earth ground. If the system's neutral AC leg is at earth ground potential then the isolation transformer is not working. This is a safety feature. If someone grabs the hot side of an isolated system and grounds his other hand in the ocean, there should be no injury. All he/she did was to provide a reference for the hot side of the circuit.
Update On Zinc's
Well I thank everyone for their advice, but I am not sure I accomplished anything yet. Today I took my new 3 prong yellow circuit tester (that's a nifty device Dan), and tested every socket (I know that was overkill), and the dock outlet. No faults registered. I then looked for the galvanic isolator, (boy did they bury that), found no loose wires. How do you know it's working? Assuming I could get to it, I have no idea how to test it. Checked all the grounds I could find including the connections on the battery selector switch. No problems. Even checked to make sure shaft was properly electrically bonded to the engine, it was. Checked to make sure DC and AC grounds were common. They are. I went to the marina and asked them to check the areafor stray currents, they will do that next wee, but the boats around me do not seem to be having the problem. By the way, my reverse polarity light is not on. I'm stumped, looking for more suggestion Thanks in advance for all your support so far
Well I thank everyone for their advice, but I am not sure I accomplished anything yet. Today I took my new 3 prong yellow circuit tester (that's a nifty device Dan), and tested every socket (I know that was overkill), and the dock outlet. No faults registered. I then looked for the galvanic isolator, (boy did they bury that), found no loose wires. How do you know it's working? Assuming I could get to it, I have no idea how to test it. Checked all the grounds I could find including the connections on the battery selector switch. No problems. Even checked to make sure shaft was properly electrically bonded to the engine, it was. Checked to make sure DC and AC grounds were common. They are. I went to the marina and asked them to check the areafor stray currents, they will do that next wee, but the boats around me do not seem to be having the problem. By the way, my reverse polarity light is not on. I'm stumped, looking for more suggestion Thanks in advance for all your support so far
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