Cabo Express Electrolysis

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.

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.

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.

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???

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 .

CE is the European equivalent of our UL or underwriters laboratories

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.

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.

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.

A high quality reference electrode and even a cheap multimeter will save several hundred dollars over that WM product. The only difference is your cheap meter doesn't have the pretty colored background on the meter display. After looking at a chart a few times you should be able to remember what a "good" reading should be.

http://www.reliabilitydirectstore.com/RDI-CRE-Corrosion-Reference-Electrode-p/rdi-cre.htm