H23.5 electrical shock

Jun 2, 2004
649
Hunter 23.5 Calgary, Canada
After 15 seasons with my H 23.5, I thought I knew everything I needed to know about this boat. After searching I only found one similar post but it was for a much larger Hunter.

With with my swim ladder in the water and my feet on the top bracket of the ladder ladder, I bent over to reach the rudder and thought I got bit on the thigh by some bug. It turned out I was getting an electrical shock when touching the stern rail seat. It's not strong enough to feel with my fingertips but very noticeable on more sensitive skin. I lifted the electric start Yamaha 9.9 out of the water but the shock is still there.

It happened just now and I'm still sitting in the boat. If it makes any difference, from my Marina I motored about 5 minutes and dropped the anchor. The chain is on the bottom with rope ride to the boat. I'm in 15 feet of water on our fresh water lake. I'm also under three triple wire high tension power lines, but LOL I hope that is not the problem!

I disconnected both leads from the battery and to my surprise, the shock is still there!

What could it be?

Rick
 
Jun 2, 2004
3,390
Hunter 23.5 Fort Walton Yacht Club, Florida
Induction from your magnetic personality is my best guess.
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
Did I read it right? I happens under the power lines? There may be enough energy for the mast to pick it up and you become part of the path when you touch metal.
 

walt

.
Jun 1, 2007
3,511
Macgregor 26S Hobie TI Ridgway Colorado
Calgary Canada today - partly sunny so can we assume this is not due to T storms.

If you get a single shock when you touch the ladder (which I assume is metal and one side is grounded), this could be due to Corona current from the electric field from the overhead wires (if they are high enough voltage). You and possibly some ungrounded metal structure form a capacitor to ground that gets charged by Corona current. When you touch the grounded ladder, the capacitor gets discharged. The discharge would be a single zap.. not a continuous shock.

You would need to not touch the grounded ladder for a while, then Corona current due to the overhead electric field could charge you up (ie, charge the capacitor) again. It would always be a single zap, then you would need to wait a while not touching the ground before you get a single zap again.

This is just a guess since we dont know the potential of the wire above your head or how high it is. If you did know, you can find out about what the electric field you have and compare it to what is required to produce Corona current.
 
Nov 6, 2006
9,884
Hunter 34 Mandeville Louisiana
Static electricity, most likely.
Ya been rubbing on any cats lately?
 
Oct 3, 2014
261
Marlow-Hunter MH37 Lake City, MN
Calgary Canada today - partly sunny so can we assume this is not due to T storms.

If you get a single shock when you touch the ladder (which I assume is metal and one side is grounded), this could be due to Corona current from the electric field from the overhead wires (if they are high enough voltage). You and possibly some ungrounded metal structure form a capacitor to ground that gets charged by Corona current. When you touch the grounded ladder, the capacitor gets discharged. The discharge would be a single zap.. not a continuous shock.

You would need to not touch the grounded ladder for a while, then Corona current due to the overhead electric field could charge you up (ie, charge the capacitor) again. It would always be a single zap, then you would need to wait a while not touching the ground before you get a single zap again.

This is just a guess since we dont know the potential of the wire above your head or how high it is. If you did know, you can find out about what the electric field you have and compare it to what is required to produce Corona current.
I was going to post something to this effect but it wouldn't have been nearly so well explained so instead I'll just say:

^ this
 
May 24, 2004
7,129
CC 30 South Florida
That happened to me as I leaned on a wet tree that was under high tension power lines.
 
Jun 2, 2004
649
Hunter 23.5 Calgary, Canada
hey rick, did you notice your rudder lock in my engine well?

Corona? Since I retired 6 years ago I can't afford Corona and switched to a local beer that's half the price. It doesn't save money though because I drink twice as much.

I haven't read any of the links yet but I have some more info.

I re-attached both battery leads and just begore going for a swim I tested for the shock. It had been continuous but now it's gone. I had mentioned that I had just finished motoring in in case it's possible or a static charge to build up from moving through the water ?

After the swim and typing the above, I tested again before hitting the POST button and it's back but very weak now. I may have missed it before the swim. I guess I'll continue testing he battery and read those links.
 
Jun 2, 2004
3,390
Hunter 23.5 Fort Walton Yacht Club, Florida
Yeah I did.

Still think the zap is your personality, why it is coming out so near your posterior is for another post.
 
Jun 8, 2004
10,024
-na -NA Anywhere USA
The boat described is not at a marina nor near a boat house/docks but instead under a power line in the water. Assuming the motor is not running is puzzling. Under a power line of course would not be my cup of tea to anchor out underneath. Do you have a dual battery system and if so, can you turn it off and check with a meter when that happens again moored out? I am confused. Whenever being rescued by a helicopter while in the water, when the wire with sling comes down, pilots are trained to let it hit the water to discharge static electricity first or be shocked. Maybe I am wondering but I am going back to investigative days which is why I brought this up wondering. Could you have a faulty battery or miswired wires? Again I am fishing here as you are not near a boat, marina or docks.
 
Jun 2, 2004
649
Hunter 23.5 Calgary, Canada
I have a single battery. The ACC panel switch is always on to run the bi-data depth and speed display. There is wiring for a 12-volt cigarette-lighter socket tucked in above the above the aft berth behind the companionway step, and a socket above the engine well for my old Autohelm autopilot.

I have made no modifications in recent years. The boat was unattended for 2 weeks until a few days ago. Some storms passed through while I was gone so the boat would have been tossed around as the marina is not protected. There is no electricity or water service on the docks.

After posting here I remained at the day anchor site for a few more hours, with the battery connected and the swim ladder in the water. Before leaving I tested for shock and there was none. I started the engine and went forward to lift the anchor. As soon as I lifted the last of the rode and touched the chain I got a shocked on the leg from the pulpit. I have to sit when I haul it up due to a bad back. This shock was the strongest felt yet. There is no way this isn't a new phenomenon as I've done this scenario countless time every summer for years. I went to the stern and tested the swim ladder to stern rail circuit as described above and there was little or no shock (hard to tell a very weak shock from the feeling of cold stainless steel on bare skin). I motored back to my slip and tested the stern rail again and there was little or no shock.

Rain clouds were coming so I didn't do any more tests at the dock. It's cold and raining today so I won't be going to the marina today.

The electric start Yamaha 9.9 has a charging circuit (maybe 6A like my Honda was?) but if like my old Honda, it doesn't kick in at idle speeds which was the case when it was running while I lifted the anchor.

When the weather improves I'll do some tests at the dock, such as test the stern rail and pulpit locations before and after starting the engine. If the running engine gives me a pulpit shock I could disconnect the charging wires which attach to terminals above the engine well.

I'm baffled. Suggestions for more things to test are most welcome!
 
Jun 2, 2004
649
Hunter 23.5 Calgary, Canada
Yesterday I went to the boat and did some tests at the dock. With the the ACC circuit on and engine, swim ladder and anchor all in the water (as was the case when I first discovered the shock), I checked both the swim ladder/stern rail and the pulpit and there was no shock. Then I started the engine and tested at idle and revved up speeds, and no shock.

So next time I'll motor but not to the powerlines and check, then motor to the powerlines and check.
 
Jun 8, 2004
10,024
-na -NA Anywhere USA
Rick;

As I understand the only place this is occurring is under the power lines. Otherwise, nothing occurs and of course not at the docks as no power is turned on. I do not feel you have any short with the engine based on what you are reporting. I have a feeling that the power lines where you are at are discharging into the water and I am thinking an insulator on the tower might be suspect. I would again specifically detailing what is happening and where that this is happening if not done so to the public or governmental agency who oversees that power line as this is a safety issue that could cause electrocution and copy the power line company. This then will make the power line company from dragging their feet when a governmental agency is involved. It is best to have this checked out because I have seen one fellow electrocuted in the water and another friend of mine, his son the same thing on the docks. I would avoid that anchorage for now until you get a response.
 
Jun 2, 2004
649
Hunter 23.5 Calgary, Canada
The weather is nice today so I'm out on the boat doing some more tests. I motored a similar distance from the marina in the opposite direction of the power lines, dropped the anchor and the swim ladder, and no shock with or without the engine running. Then I motored back to the spot under the power lines and dropped the anchor and swim ladder and zap, quite a good continuous shock there. There are three towers and I was right in front of the one that's closest to the shore, so I moved over to the third tower which is further back. The shock was still there but much less. There are three other places where I anchor near or under these power lines on the lake, and none of them produce an electric current. The other locations have much higher towers and are father from the shore.

I will report this as suggested by Dave.
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Oct 3, 2014
261
Marlow-Hunter MH37 Lake City, MN
Big towers!

In that area, those towers are likely going to be transmitting power at 240kV, AC and based on your photos, you have three circuits in parallel. They're moving a lot of power!

Between those power conductors and "ground", there is a voltage gradient from 240,000 volts to 0.0 volts and that doesn't happen as either a step change or a linear change, but inversely proportional to the square of the distance, as I recall. When you sit underneath that tower, your aluminum mast provides a better path to ground for the voltage to decay compared to the air around you. When you touch the stern rail seat and the rudder you also are now presenting a better path to ground between the rail and the rudder than it had before (fun fact, your body has roughly 500 ohms of resistance, from foot to hand).

You can report this, but I'll bet you a cup of coffee that the utility will tell you this to be expected and nothing will change. If the shock is enough to feel, I'd be hesitant to anchor there. Not from a health standpoint, but from the risk to any boat electronics.
 
Jun 2, 2004
649
Hunter 23.5 Calgary, Canada
In an effort to determine if the leakage is through the air to the mast or through the ground, I had repeated the test under the tower on the far left. It was very faint there but very strong by the one on the right. The height of the cables is the same but the distance of the towers from the shore is different, so I'm leaning towards the ground theory.

It doesn't show in these photos, but ground water seeps out of the cliffs all around the lake. I think it slows or stops in most places if there hasn't been much rain. There has been a lot of rain lately, so maybe the wet (wetter) ground is contributing to this? We had more rain since my first post and the current seemed even stronger today.

If I grab the stern rail with a full hand grip, as I do when swimming and climbing back up the swim ladder, I can't feel the shock. It's only felt when you brush it lightly, especially sensitive skin. Perhaps that's one of the reasons why I never noticed this in all the years I've anchored to sun and swim there. Other reasons being all the recent rain and the fact that I usually anchor under the center tower's lines where it seems to be weaker.
 
Oct 3, 2014
261
Marlow-Hunter MH37 Lake City, MN
In an effort to determine if the leakage is through the air to the mast or through the ground, I had repeated the test under the tower on the far left. It was very faint there but very strong by the one on the right. The height of the cables is the same but the distance of the towers from the shore is different, so I'm leaning towards the ground theory.
Interesting test comparing the far tower with the near tower. Water is actually not a great conductor so what you saw makes some sense. I don't think it has to be either/or with respect to the mast vs. the ground though. The mast is definitely a better path than air. To what extent it contributes to the shock is unknown.

I think you're correct in thinking the recent rains could have contributed to the effect. While dry ground are terrible conductors, the wet soil makes a great conductor.

Next time you're there take a length of wire, secure one bare end to your rail and drop the other end into the water. No more shocks.