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Cabo Express Electrolysis

Discussion in 'Cabo Yacht' started by BillManthorne, Nov 11, 2014.

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  1. BillManthorne

    BillManthorne Member

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    I have a 2000 45 express with MANs. My props got burned by electrolysis pretty bad. Starboard is worse than the port and my trim tab zincs get eaten too. Starboard is eaten 2x as fast as port.

    Checking all my bonding wires, and based on the amount of burn, I've been told it is a very "active/hot" issue based on the green hue around all the pits. This has gotten worse over the past 2 years at 2 different marinas. So I know it is a boat issue and it seems to be degrading. Any thoughts? Galvonic Isolator, Altenators, AC... etc? BTW, my MANs have two alternators on each engine...anyone else have that set up? Obviously I need to get a good marine electrical shop onboard.... but any ideas would be great. I can hardly wait to get the bill for 2 new 28x45 props.

    My main question: Has anyone put external zincs on their shafts in addition to the shaft brushes in the engine room? I thought I was told not too, but I'm not sure.

    Thanks,

    Bill
  2. captholli

    captholli Senior Member

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    Sounds serious, Do you have polarity lights on your switch board for AC and DC? If not I'd consider enlisting / hiring a reputable ABYC Marine Electric tech to perform a electrolysis survey followed or combined with a
    corrosion analysis survey aboard. Is any of your sea water "hard" plumbing being eaten from electrolysis ? zinks in your mains or machinery wasting prematurely ? All are signs of stray current or ground fault.
  3. BillManthorne

    BillManthorne Member

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    I do have polarity lights. They show normal. Thru hulls look good, but they need to be looked at more carefully.
  4. Capt Ralph

    Capt Ralph Senior Member

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    Have you owned the ship before this was an issue? Any work or mods performed before your hardware started dissolving.
    Two different marinas may not mean much, There are more than a few hot boats out there eating up their neighbors hardware.
    They most reliable way to get this resolved is getting the right tech out there.
  5. Capt J

    Capt J Senior Member

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    First thing I would look at is your shorepower cable and it's connections, next would be the wiring on your air conditioning raw water pump. Did anyone replace the end on it and mix up the ground and the earth-wire? You can buy the Professional mariner box that measures galvanic corrosion West Marine # 14121503. You will also need an extension lead for it. You basically put the lead into the water and clip the end next to the box on each thru-hull and other fitting and measure it. They're around $400 from West Marine with everything you need. You need to solve the problem asap, not put more zincs on.

    I would hire a marine surveyor or marine electrical outlet that can measure the problem. Your boat should be easier as access to electrical is pretty good and it doesn't have too many a/c systems. If you want to test yourself, hook the box up to a shaft (the one with the prop with the most corrosion). Turn off all a/c breakers and then unplug your shorepower cable from the boat and note the reading. Next plug the shorepower in and turn only the shorepower breaker on, see what the reading is. Next turn each item on, 1 by 1 and see if the reading changes. When you get to the circuit that is throwing a lot of current you probably hit the right one. BUT, note it and then turn on all your normal breakers and items and see if it increases even more. If it increases a lot more it's most likely a grounding issue in the cable, if it's only on that break (such as helm a/c) then it's probably either in the wiring or the item itself. If you don't get any high readings with this, start the generator, see if it changes, next 1 engine and the next engine.....it's possible it could even be an alternator.
  6. Capt Ralph

    Capt Ralph Senior Member

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    Purchasing that $335 meter could be fun but as many electronic devices, hard to justify for a keeper in a normal tool kit. I have no idea what an experienced tech would charge but I think he would be a better value and hold more clout if it's an environmental (Not your boat) issue.
  7. Capt J

    Capt J Senior Member

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    Marine Electricians charge $105 hour here and they're not fast. The meter would pay for itself in 1 set of zincs that the OP is probably going through every few weeks. Plus you can always check it in the future. Would a professional be the best route, yeah. Is there one in his area? Who knows. If he had hired one, he wouldn't be here asking us.
  8. BillManthorne

    BillManthorne Member

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    Thanks for the replies. Have owned the boat since 07. Just started having this problem last year and it seems to have become worse this year. Interesting you should mention the AC raw water pump. That was replaced 2 years ago and the marina upgraded it and moved the location. Not sure it matters but that is on the starboard side (worst damage). I also had the 110 freshwater pump replaced. The marine installed an outlet in the forward compartment (under cabin sole) to plug the pump into for easy replacing in the future. Could that also be draining current since they didn't use butt connectors?

    I also had the engine mounts replaced on the starboard motor 2 years ago. Would that that cause any grounding issue?

    Do any of you put external shaft zincs on?
  9. Capt J

    Capt J Senior Member

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    I wouldn't put external shaft zincs on that boat as it disrupts water flow to the cutlass bearings and is why Cabo used shaft wipers and a transom zinc.

    I wouldn't think motor mounts would have anything to do with your electrolysis issue.

    Installed an outlet for easy replacing of the pump in the future??? This makes no sense as it only takes minutes to splice the wires and the freshwater pump lasts years and years. I alse would look at how this pump is wired as I think the origional pump was 240v. Also, if they wired the pump wrong at the pump as there are a few ways to wire them to either make them 120 or 240v, and this is where your wiring is probably screwed up.

    Why would they move the a/c raw water pump when it was in a good location from Cabo to begin with???

    I would get a knowledgable marine electrician out (not the boat yard who did the work), and specifically investigate these items.

    Cabo built a really good boat that could even be CE certified (and many were), and everything is very well located, well thought out, and really well wired on your boat. Why would any marina feel the need to re-wire or re-locate anything on your boat???
  10. captholli

    captholli Senior Member

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    If you prefer to delv deeper by yourself than Capt J had a good trouble shooting plan that can be carried out with a good multi meter set on mil volt. Take your meter to a solid ground point and use a extension wire to keep the same ground point throughout the test. Next take the positive lead to your through
    hulls and other bonding points with the VOM set to milavolts. Have someone turn breakers off one by one while you read the meter for the loss of voltage. If you have sub panels than isolate the circuits that way. I've found ground faults in florescent starter ballasts on the AC side as well as DC faults this way. If nothing shows in the breaker test than un plug from the dock and observe the meter. If you have a change at that point than your diode isolator /galvanic iso is bad or you if you have a shielded isolation transformer between the dock power and panel that would be the culprit .
  11. BillManthorne

    BillManthorne Member

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    Thanks again. The Fresh water pump is still located up under the cabin sole. Not sure why the marina put an outlet up there... as you said the freshwater pump lasted for years... not sure if the outlet could be causing the problem. The raw water AC pump was upgraded to a sealed water-cooled heavy duty pump and moved to a serviceable location. the old pump was air-cooled and located under the ac compressors. It was an absolute ***** to get to... I'm guessing this pump might be the issue.

    Capt. J, you mentioned 240 volt pump. Are you talking about the AC pump or freshwater pump? Also, what did you mean be CE certified.

    The boat is out of the water for the winter, but I have a call into a marine electrician. I want this fixed before next year. Props are 13K....good god.
  12. captholli

    captholli Senior Member

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    CE is the European equivalent of our UL or underwriters laboratories
  13. Capt J

    Capt J Senior Member

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    The air conditioning pump was 240 volts for certain. I believe the freshwater pump is a 240 volt pump origionally installed by Cabo, them switching it to a receptacle and plug indicates a 120 volt water pump was replaced. I am not 100% certain Cabo origionally used a 240 volt pump for the freshwater pump as it's been a while since I've been on a 45' cabo. But if they did and they re-wired it for 120volts, chances are they have the wiring screwed up and this is where your problem lies. Not sure if a marine electrician can sort it out as easily, out of the water.
  14. BillManthorne

    BillManthorne Member

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    I had my new marina check... the ac pump is 115v.....
  15. BillManthorne

    BillManthorne Member

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    Ok. My marina has checked and the AC raw water pump is supposed to 115v not 240. Not sure if that is good or bad... not the issue might not be as cut and dry. I hate electrical problems.
  16. Capt J

    Capt J Senior Member

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    The air conditioning raw water pump, should be 240 volts on that boat. Can you take a picture of your ac power breaker panel. You should have a double pole breaker, on the 240volt section of your panel. Where the breaker is located will tell you everything. The air conditioners and the air conditioning pump should be 240 volts and were on all 45' Cabo's that I know of. The pump can usually be wired to work on either 120V or 240V (unless it's a march with the plastic end), but it should have 240V going to it and be wired for 240V. If they have attached the wires to the 120V legs then this would most likely be your problem.

    The freshwater pump could go either way 120V or 240V, I cannot remember for certain and I don't have one to look at.

    I am almost certain that "your marina" that did the work on the boat and changed the freshwater pump and air conditioning raw water pump, is the problem. The problem started 2 years ago and nothing else has changed. You really need to get someone that is a certified marine electrician on the boat (not from your marina). If they can determine that it was the a/c raw water pump mis-wired, then the marina would owe you a set of props. I would also have a marine surveyor take a REAL Good look at every single thru-hull on your boat.

    Understand that I have worked on and have run at least 15 different Cabo 45's over the years, and have even fished on Hull #1 to give you an idea. As well as at least 300 different Cabo's in total.
    Last edited: Nov 12, 2014
  17. Capt Ralph

    Capt Ralph Senior Member

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    Hey Skip, What voltage does your A/C pump run on?
  18. Capt J

    Capt J Senior Member

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    The only Cabo's that had 120Volt a/c pumps was the 35' Cabo both FB and express, and the 31' express. The 32' express even had a 240volt a/c raw water pump as well as everything larger.
  19. BillManthorne

    BillManthorne Member

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    Thanks again. I will have to wait for the electrician to get on the boat. His company also installs marine AC systems so that hopefully will help confirm the issue. That will really suck if the screwed this up. I have a couple other questions about the mans. I will send you a pm. THX!
  20. Marmot

    Marmot Senior Member

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