Sparks from the Backstay

[Charlie]

I have a few problems with the electrical system on my boat and was wondering if anyone could help me to track down the problem.

1) When the bows from my bimini touch the backstay, at night, I can see sparks flying. This also shorts out my running lights and trips the breaker. As long as I keep the bows away from the backstay the running lights do not trip.

I am going to inspect the insulator on my backstay for the SSB antenna to see if that is still good. This happened when the SSB was shut off.

2)In three different spots along the toe rail on both port and starboard I have something (I think electrical current) that is eating up my toe rail. One is near the bow. This one is not too bad (but still needs to fixed) The second one is at a scupper a foot or two behind the fuel inlet. This is the worst one and I had pieces of the toe rail and a stainless steel bolt flake off. The third one is at the stern end of the toe rail. It is in between the first and second as far as severity with pieces of the toe rail roughened but not flaking off.

My concern is that somehow I have created a battery between the aluminum
of the rail and the steel. All three areas left rust marks and had a white powder that surrounded them. While cleaning off the powder with vinegar is when I found out about the problem. I am not positive but I believe that all three spots on the toe rail have bonding wires near them.

and 3) My windlass is wired as follows a) inline with the battery is a 100 amp breaker. The wire goes to the solenoid and then to the windlass. from the solenoid I have a light wire that runs to a pull switch located in the anchor locker. This switch needs to be on for the windlass to operate. The anchor locker switch runs to the foot switch which allows the retrieval of the anchor. The problem is that the off/on switch in the anchor locker gives you a shock when you pull it on or turn it off.

I recently did the Baja Bash and mistakingly left the windlass breaker on as I went up the coast for the first leg. I don't know if this contributed to the shock on the anchor locker switch.

The rust and such on the toe rail started before I departed Mexico for the US.

[skipmac]

If you are seeing sparks you have way more going on than galvanic reaction between dissimilar metals. I think most likely you have a wire shorting somewhere and putting voltage into your boat's structure. Is your boat bonded? If yes and there is an electrical leak anywhere in the system it will be fed everywhere.

Other possibilities, electrical fault in appliance, electronics or some equipment somewhere.

You need to get a meter and track this down. If you are already seeing corrosion you could be eating up your prop, rudder post or who knows what.

If you see obvious sparks between the backstay and the bimini frame then connect a volt meter between the two and check the reading. Test AC and DC readings.

[S/V_Surya]

I can tell from your description that you have serious electrical issues. If you are not electrically inclined you need to get an marine electrician to check it out. For example it sounds like the pull switch in the anchor locker is wired in series with the foot switch. You get shocked because you are the path to ground when you touch it. Not good.

[Charlie]

Originally Posted by skipmac

If you are seeing sparks you have way more going on than galvanic reaction between dissimilar metals. I think most likely you have a wire shorting somewhere and putting voltage into your boat's structure. Is your boat bonded? If yes and there is an electrical leak anywhere in the system it will be fed everywhere.

Other possibilities, electrical fault in appliance, electronics or some equipment somewhere.

You need to get a meter and track this down. If you are already seeing corrosion you could be eating up your prop, rudder post or who knows what.

If you see obvious sparks between the backstay and the bimini frame then connect a volt meter between the two and check the reading. Test AC and DC readings.

Thanks for the possibilities to look. The boat is bonded. I have checked my zincs and the prop and they seem to be fine. If I connect a voltmeter between my bimini and the backstay would I get a reading since there is no ground? I am reasonably proficient with electrical but this one is right on the edge of my grasp. If anyone could give me specific tests to run that would be great.

[skipmac]

Originally Posted by Charlie

Thanks for the possibilities to look. The boat is bonded. I have checked my zincs and the prop and they seem to be fine. If I connect a voltmeter between my bimini and the backstay would I get a reading since there is no ground? I am reasonably proficient with electrical but this one is right on the edge of my grasp. If anyone could give me specific tests to run that would be great.

Don't need a ground. If you see a spark between these two then one has a higher voltage than the other. If you connect a meter set to volts between the two it will show the voltage difference between the two. That is your circuit. What you are doing is trying to measure the spark that you see.

If you have a digital, autoranging meter (it will automatically set to high, medium or low power range) just start with AC and see if you get a constant reading. A quick jump and then back to zero would have possible other meanings. Then try setting the meter to DC and repeat the test. Record what you find and come back to the forum.

[DeepFrz]

Lets start one thing at a time.

Start by making sure that all AC is turned off. No inverter, no shore power and see if that changes the situation with the lights.

If it doesn't then at least the bimini part of the situation is strictly dc to ground. In that case I would suspect that you have a short from your nav. light wiring to the bimini and when it touches the backstay it shorts out your nav. lights.

[Charlie]

Originally Posted by skipmac

Don't need a ground. If you see a spark between these two then one has a higher voltage than the other. If you connect a meter set to volts between the two it will show the voltage difference between the two. That is your circuit. What you are doing is trying to measure the spark that you see.

If you have a digital, autoranging meter (it will automatically set to high, medium or low power range) just start with AC and see if you get a constant reading. A quick jump and then back to zero would have possible other meanings. Then try setting the meter to DC and repeat the test. Record what you find and come back to the forum.

Thanks Skipmac it will be a week or more before I can get to the boat. but I will do that when I can

[Jim Cate]

G'DAy Charlie,

Well, if (as you report) touching the bimini bow to the backstay shorts out the running lights and blows their breaker, then it is very likely that the running light positive lead is now connected to one of these items, and the other is at ground potential. Use your DVM to measure the voltage (DC) between each of these items and the ships ground. I expect that you will find 12 VDC on one or the other. Then you will have to trace the wiring to the running lights and find where it has chafed through (or otherwise lost its insulation) and is now connected to the bow or the stay. One place to look might be where the pivots for the bimini bows are screwed to the boat. A nice sharp point just might be poking into the wireway.

Good luck with it.

Cheers,

Jim and Ann s/v Insatiable II lying Salamander Bay, Pt Stephens, NSW, Oz northbound at last

[Charlie]

Originally Posted by DeepFrz

Lets start one thing at a time.

Start by making sure that all AC is turned off. No inverter, no shore power and see if that changes the situation with the lights.

If it doesn't then at least the bimini part of the situation is strictly dc to ground. In that case I would suspect that you have a short from your nav. light wiring to the bimini and when it touches the backstay it shorts out your nav. lights.

Thanks Deepfrz I had the sparks occur when we were out sailing. The only inverter that I had on was a small one that I use to power my laptop. I will try again w/o the inverter on.

Originally Posted by Jim Cate

G'DAy Charlie,

Well, if (as you report) touching the bimini bow to the backstay shorts out the running lights and blows their breaker, then it is very likely that the running light positive lead is now connected to one of these items, and the other is at ground potential. Use your DVM to measure the voltage (DC) between each of these items and the ships ground. I expect that you will find 12 VDC on one or the other. Then you will have to trace the wiring to the running lights and find where it has chafed through (or otherwise lost its insulation) and is now connected to the bow or the stay. One place to look might be where the pivots for the bimini bows are screwed to the boat. A nice sharp point just might be poking into the wireway.

Good luck with it.

Cheers,

Jim and Ann s/v Insatiable II lying Salamander Bay, Pt Stephens, NSW, Oz northbound at last

Thanks Jim. Just so I am clear I will need a wire running from my ships ground hooked to the DVM and then test the backstay and other items to see if there is any current. Is that correct?

[Bash]

my guess is that the first time you try this with a voltage meter you won't get any reading. If this is the case, then turn on the running lights and repeat the test. If you get a reading at this point, it's time to rewire the running lights.

[Opie91]

Charlie,

You can also try turning off every breaker you have. See if the arching is still present. If the problem is not there turn each breaker on one at a time. Check for the issue again. If you find one, still check the rest of the circuits it sounds like you have multiple problems.

It could be simple as a bad switch for the windlass or someone reversed the polarity of the nav light the last time the mast was stepped.

Good luck.

[Jim Cate]

Originally Posted by Charlie

Thanks Deepfrz I had the sparks occur when we were out sailing. The only inverter that I had on was a small one that I use to power my laptop. I will try again w/o the inverter on.



Thanks Jim. Just so I am clear I will need a wire running from my ships ground hooked to the DVM and then test the backstay and other items to see if there is any current. Is that correct?

Yep, sorta: You will not be measuring current, but a voltage between the two items. But yes, you will need to connect the "black" probe to the ship's electrical ground. And as Bash says above, do it with the running lights switched both off and on.

Jim

[um saudade]

Hire somebody competent to track this down. While it may be as simple as a crushed positive wire it could be a combination of several things that have not been correctly done. Why is it that when electricity is easily one of the most critical parts of the sailboat's working apparatus, nobody wants to hire competent help but everyone seems eager to buy a cheap meter and become an overnight electrician?

There is no free lunch and there is no short course in getting there. When anything on a boat shocks you, you shut it all down and fix it, right now unless you are in force 6 or better or the boat is sinking anyway.

Turn off everything except the bilge pump circuit and get help before you eat big holes in very expensive hardware.

Um Saudade