Electrical Leakage Checks On The Hard?

[zstine]

Electrical gurus, Are there any electrical checks I can do on the hard to see if I've got leakage or something that would cause me to loose zinc?
For 3 years I've been going through 2lbs of zinc every 3 months. (1975 Tartan 41). The first 2 years I blamed the marina environment and installed a galvanic isolator, which didn't help. Last year I was on a mooring, but still eating zinc. so I know my boat is the issue. This winter I installed a new negative terminal strip, reterminated a bunch of wires and ripped out a bunch of unused wires that the PO left in after upgrades and I replaced the bilge pump and wires. I'm stripping and epoxy coating the keel, again, 3 years in a row. The electrolysis blows off the epoxy every year. I'm considering blasting the keel ($550) because sanding doesn't get to clean metal as the corrosion is like little worm holes that are maybe 1/4 inch deep. Obviously I can't sand down through 1/4 inch of lead. But I don't want to waste my money on blasting if electrolysis just blows the epoxy off again. SO, Are there any electrical checks I can do on the hard to see if I've got leakage or bad grounds, etc.?
Battery neg is bonded to engine, which should be connected to the shaft electrically, and the engine is bonded to the keel, which is attached to the mast. At the end of last season I lifted the bond from the engine to keel to hope the floating keel would not loose lead like it has been. Through hulls float on my boat.

[Bleemus]

From your description it would appear the problem is generated by your boat. I will let the experts provide advice about how to proceed but you are on the right track trying to deal with it finally.

[boatpoker]

How are you charging batteries while on a mooring ?

[zstine]

Originally Posted by Bleemus

From your description it would appear the problem is generated by your boat. I will let the experts provide advice about how to proceed but you are on the right track trying to deal with it finally.

my boat for sure! I'm hoping the experts will chime in here.... Any experts willing to suggest a test procedure?

Originally Posted by boatpoker

How are you charging batteries while on a mooring ?

Charging on the mooring... I installed 530W of solar last year. The solar did not have any impact on the amount of zinc I go through. The only electrical change I made coincident with the beginning of this problem was the install of a BlueSea systems battery monitor. I have re-done all that wiring. Is there a way to test if that component is the problem?

[boatpoker]

so no battery charger involved ?

[zstine]

Originally Posted by boatpoker

so no battery charger involved ?

The solar is connected to an mppt charge controller, but I have not plugged into shore power and used my battery charger in over a year.

[freshalaska]

Do you have an inverter on board? If so try isolating it and see what happens. Reverse polarity in the ac can cause these problems.

[DeepFrz]

Your DC ground and your bonding system should be completely separate. I'm not sure how your DC ground bus is set up but it should be the main ground, not your engine. Engine should have a ground lead to the DC ground bus. DC ground should not go to your keel.
https://www.westmarine.com/WestAdvis...unding-Systems

[zstine]

Originally Posted by DeepFrz

Your DC ground and your bonding system should be completely separate. I'm not sure how your DC ground bus is set up but it should be the main ground, not your engine. Engine should have a ground lead to the DC ground bus. DC ground should not go to your keel.
https://www.westmarine.com/WestAdvis...unding-Systems

Thanks DeepFrz... So if the engine is connected to DC ground, and the DC ground should be separate from the bonding system, then that means the engine and shaft is not in the bonding system.. right?
The boat when purchased had a negative battery cable going to the engine block, then a heavy copper wire connected the engine bed/foundation (steel) to the keel and a similar wire to the mast step. I have lifted the 'bond' wire from the engine bed to the keel at the end of last season, but too late to prevent keel damage and tell if it had any effect. While I have not yet read the whole article linked (i will) my DC negative is exactly like Figure 1. And I basically have no bonding at all. My rudder, through hulls, keel all float now, with only a lightning protection wire from mast to keel... Are there any electrical checks I can do on the hard to ensure I won't continue to eat lead away?

[exMaggieDrum]

Inverter chargers can often cause leakage, or just battery chargers too. Usually from using a cheap I/C or charger, especially not marine rated. Your AC grounding system may be causing a problem too. I would disconnect the (supposed to be one and only one) AC ground to DC ground and see if you have any continuity to the AC system from the DC system. I/C's may only cause the problem when they are in charge mode so it should be on when you do that. If you don't know how to safely deal with active AC systems get an experienced tech to do this.

There is a way to check out your whole DC bonding system which might possibly be making a problem but it takes a tech some time to do it right. On the hard is easier but they have to have the right meter to do it. It can be done in the water too with the right equipment. The rule is everything bonded or nothing bonded. If you have bonding to all your underwater metal, including prop shaft, unless insulated from the motor, you need to inspect and replace any suspect bonding wire and terminals for perfect continuity to the fixture. Daisy chaining bonding systems is not a good idea but common, as is the use of strap above or embedded in the hull glass. This often fails - often.

When in the water have a tech, or the marina, check for any AC leakage by putting a clamp on ammeter to your AC pylon cable. A reading would indicate leakage from AC to the water - a very dangerous thing, which will eat up zincs like crazy. It will eat up your neighbors' boats zincs like crazy too. There are also specialized test tools that can be used by techs and many marinas to check for this. It often is from I/Cs that have a problem. Marinas are supposed to disconnect the AC and red flag any boat with AC leakage as it can kill someone very quick in the water anywhere near the boat.

[bsurvey]

can't do too much on the hard. you need to float the boat, turn on all the systems and drop a silver silver chloride half cell over the side. then start turn switches on and off and watch the voltage.


my guess its you automatic bilge pump only thing that operates on a mooring Right?

[Oceanride007]

Its normal on ships to have earth lamps on every DC and AC circuit. They use meters now but lamps is easy to rig, the principle is that a the lamps are half brilliant normally, but when the test button is pressed, one will dim, the other will brighten. When set up, disconnect each circuit in turn, till you capture it. There should be a image attached.

If not there, Two lamps connected across the load, at the midpoint between the lamps, a test switch connects the circuit to the bonding system/hull.
If your battery negative is connected to Hull (Mine is) it may need to be disconnected for the test.

[Oceanride007]

2nd attempt with the image.

[kish]

Corrosion Reference Electrode Product Specifications

Corrosion Reference Electrode and User's Guide
by ABYC-Certified Corrosion Experts

"
The Corrosion Reference Electrode is an extremely useful test and diagnostic tool that should be included within the toolbox of every boater and marina operator. When plugged into your digital multimeter you get answers to questions such as:

"Do I have enough zinc on my boat?"
"Are my shaft zincs still attached?"
"Is my bonding system working okay?"
"Are boats next to me eating my zincs?"
"Is my galvanic isolator working?"
"Is all of my electrical equipment installed correctly?"
"Do I have stray electrical currents either in my boat or at my dock?"
"Is my dock and/or marina operating at the correct corrosion potential?"
The user's guide is written and maintained by ABYC-certified corrosion experts, and includes test methods and reference tables that help you assess, diagnose and troubleshoot corrosion problems on your boat, yacht or dock.

"

[zstine]

Originally Posted by exMaggieDrum

Inverter chargers can often cause leakage, or just battery chargers too. Usually from using a cheap I/C or charger, especially not marine rated. Your AC grounding system may be causing a problem too. I would disconnect the (supposed to be one and only one) AC ground to DC ground and see if you have any continuity to the AC system from the DC system. I/C's may only cause the problem when they are in charge mode so it should be on when you do that. If you don't know how to safely deal with active AC systems get an experienced tech to do this.

Unless I'm missing something, I'm sure my AC system is not an issue. first, I do not have an inverter charger. I have an inverter, but use the outlet on the front of it... it is not connected to my boat's AC system and I have not powered up my boat's AC for over a year. I also do not believe their is any common ground between the DC and AC... I may be wrong, but I believe all AC circuit grounds go back to the green wire out the shore power connection via diode isolation, not to any 'earth' on the boat.

Originally Posted by exMaggieDrum

There is a way to check out your whole DC bonding system which might possibly be making a problem but it takes a tech some time to do it right. On the hard is easier but they have to have the right meter to do it. It can be done in the water too with the right equipment. The rule is everything bonded or nothing bonded. If you have bonding to all your underwater metal, including prop shaft, unless insulated from the motor, you need to inspect and replace any suspect bonding wire and terminals for perfect continuity to the fixture. Daisy chaining bonding systems is not a good idea but common, as is the use of strap above or embedded in the hull glass. This often fails - often.

I have nothing bonded. I would love to hear the details about how to check the DC bonding system on the hard and what meter is needed... thanks

Originally Posted by exMaggieDrum

When in the water have a tech, or the marina, check for any AC leakage by putting a clamp on ammeter to your AC pylon cable. A reading would indicate leakage from AC to the water - a very dangerous thing, which will eat up zincs like crazy. It will eat up your neighbors' boats zincs like crazy too. There are also specialized test tools that can be used by techs and many marinas to check for this. It often is from I/Cs that have a problem. Marinas are supposed to disconnect the AC and red flag any boat with AC leakage as it can kill someone very quick in the water anywhere near the boat.

Again, I'm not in a slip, I'm moored out and my AC is never hot. If you are referring to a silver-silver chloride reference probe as your specialized test tools, I have one and can use it. I posted results on CF last summer http://www.cruisersforum.com/forums/...on-173804.html , but there was no smoking gun. I want to make these checks on the hard before I splash so I don't have to haul the boat again to make mid-season repairs.