Electrocuted swimming in marina

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Actually it isn’t electrocution but rather drowning. The small current in the water causes your muscles to lock up and when you are unable to swim you drown. That is why they are requiring GFCIs on docks now. This is typically a freshwater occurrence rather than saltwater. But I suppose it could happen in saltwater if conditions are right. The saltwater is more conducive than freshwater so the current flows around your body rather than through your body like in freshwater.
 
We are out toward the end of our dock on Lake Union in Seattle and I have to admit that we've been too bold about getting off the swim step into the water on a hot day. I've checked for current with my multimeter but I don't have a lot of confidence in the readings I get. I see divers in the water doing hull work from time to time and have kind of assumed it must be safe. A bit of a wake up call.
 
Sababa said:
We are out toward the end of our dock on Lake Union in Seattle and I have to admit that we've been too bold about getting off the swim step into the water on a hot day. I've checked for current with my multimeter but I don't have a lot of confidence in the readings I get. I see divers in the water doing hull work from time to time and have kind of assumed it must be safe. A bit of a wake up call.
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It doesn’t take much current to sieze up your muscles, if I remember correctly it takes about 60 mAmps.
 
Sababa said:
I see divers in the water doing hull work from time to time and have kind of assumed it must be safe. A bit of a wake up call.
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They are wearing dry suits for the most part. We have a very strict no swimming policy at Queen City YC because of this issue, as well as electrical inspections of all the boats.
 
I think everyone is jumping to a conclusion not in evidence. Just because said "it appeared" is meaningless. It doesn't sound like anyone was touching something that would cause current to go through a body. Current isn't just floating around in water to go through a body when it could go elsewhere in the water easier. The body has to touch a source to cause it.
 
Electric shock drowning can occur without touching anything. Electricity always returns to its source. If it is moving through the water to ground, it can paralyze a person, causing a drowning.

Read this article for a fairly recent case. 'Tip of the iceberg': Parents warn about electric shock drowning

Jim Healey’s site has a good explanation of the phenomena.

gilwellbear.wordpress.com

Electric Shock Drowning and Electrical Safety Codes

5/6/2020: Updated to add approximate mineral/salt content of different waters. Electrical Characteristics of Water: Chemically “pure” water (“distilled water,” or laboratory…
gilwellbear.wordpress.com gilwellbear.wordpress.com
 
Don L said:
So your theory of electrical current flow it is goes out, choses to go through a higher resistance person, and then loops back?
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That's why it isn't typically a problem in salt water, but it is in fresh. In salt water, the human is less conductive than the surrounding water. In fresh, the human is more conductive.
 
Don L said:
I think everyone is jumping to a conclusion not in evidence. Just because said "it appeared" is meaningless. It doesn't sound like anyone was touching something that would cause current to go through a body. Current isn't just floating around in water to go through a body when it could go elsewhere in the water easier. The body has to touch a source to cause it.
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You do not have to touch anything to have ESD, Electro Shock Drowning. The current WILL flow through the body because the bidy has less resistance than freshwater. It is actually not easier to go through freshwater than a body.
 
Don L said:
So your theory of electrical current flow it is goes out, choses to go through a higher resistance person, and then loops back?
Click to expand...
A person isn’t higher resistance than freshwater. That is why they are current does flow through a body and can cause ESD.
 
Apparently there is a lot of misunderstanding around this subject. A lot of wrong characterization here. Please do some reading on the subject, for your own safety especially if you boat in freshwater. People have fallen in marina water and get seized up, then someone jumps in to help and they can also drown. The saying “Throw don’t go” is good advice. Throw a float or something with a line on it to pull them into the dock instead of jumping in and then making 2 victims.
 
I was reading that, now that Electro Shock drowning is better understood, the thought is that many of the marina drownings where someone fell in the water and ended up dying (maybe the thought was they just couldn't swim, hit their head, might have been tipsy, etc.) were probably actually Electro Shock drowning.

I mean I'm sure many were "couldn't swim," "hit their head," "were drunk," or something but just the point is that many past cases were most likely not those things but were in fact ES drowning -- it just wasn't understood as a thing at the time.
 
Don L said:
So your theory of electrical current flow it is goes out, choses to go through a higher resistance person, and then loops back?
Click to expand...
Thanks for the reply. I don’t have a theory. Not that smart! Electrical current can be measured in water. One of the laws of electricity is that it will return to its source.

When there is an AC electrical short, in my case to a metal power box in my fridge, the charge left the boat through the bonding system (thru hulls) into the water and back to shore (to ground).

I discovered this when a diver who was going to pull a prop for me felt his arm tingling as he approached the rear of the boat. I killed the shore power and disconnected the cables. I then talked with Jim, read his site postings on how to find shorts, located the problem (after several hours work) with the power box in the fridge. Replaced it and the charge in the water was gone.
The diver was lucky that day, and so was I.

It can happen in fresh, brackish, and salt water, but is more prevalent in fresh water because the current likes the higher salt content in the human body.

As you stated, it can, and has happened when someone touches a piece of metal that is charged. But that is not the only way.

I think everyone would benefit by reading my second link above. It explains the issue pretty well.
 
Frosty said:
I was reading that, now that Electro Shock drowning is better understood, the thought is that many of the marina drownings where someone fell in the water and ended up dying (maybe the thought was they just couldn't swim, hit their head, might have been tipsy, etc.) were probably actually Electro Shock drowning.

I mean I'm sure many were "couldn't swim," "hit their head," "were drunk," or something but just the point is that many past cases were most likely not those things but were in fact ES drowning -- it just wasn't understood as a thing at the time.
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ESD wasn’t understood to be a thing until recently, maybe the last 12 to 15 years or so. So in the past I would believe that a lot of deaths were wrongly attributed to other things. I grew up swimming in marinas and never gave it a thought, guess I was lucky.
 
Sababa said:
I see divers in the water doing hull work from time to time and have kind of assumed it must be safe. A bit of a wake up call.
Click to expand...

I see people swimming in and around the houseboat marinas all the time. Is there any reason they would be safer?
 
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Sababa said:
I see people swimming in and around the houseboat marinas all the time. Is there any reason they would be safer?
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Electricity is electricity. Houseboat or trawler current leakage can kill a swimmer. One difference "might" be that on our boats we combine AC ground. DC ground and bonding. Houseboats might be wired like dirt homes.

Something worth noting about current passing through the human body. According to a buddy who is en expert in forensic investigations of electrical issues. You don't need to touch anything to have the current flow through your body. You just have to be the easiest path. He gave the example of lookie-lous wandering up to downed power lines after a storm. If the lines are still hot as you walk towards the line the potential at one foot is higher than the other. Current flows thru your body.

Same thing with a swimmer. But very minor currents disrupt the nervous system paralyzing the swimmer.
 
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I never thought much about electric current, but I would never dream of getting in the water in a marina because of the very high likelihood that a liveaboard is dumping their sewage in the water.
 
Portage_Bay said:
wandering up to downed power lines after a storm. If the lines are still hot as you walk towards the line the potential at one foot is higher than the other. Current flows thru your body.
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Often hear leave both feet on the ground and shuffle away, never lift one. Now I see hopping on one foot or both feet is also an option.
 
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Don L said:
So your theory of electrical current flow it is goes out, choses to go through a higher resistance person, and then loops back?
Click to expand...
No - that's the whole point - a human body is more electrically conductive (less resistance) than fresh water!
 
SeaDogAK said:
I never thought much about electric current, but I would never dream of getting in the water in a marina because of the very high likelihood that a liveaboard is dumping their sewage in the water.
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I’d agree regarding many marinas but it’s super tempting when you are on a finger sticking out into the lake that is full of swimmers and paddle boarders just yards away on a hot summer day. How far away from a marina does one have to be to safely swim? Why isn’t it also a risk to swim off a boat that has an inverter or is running a generator in the open water?
 
If your boat spends any amount of time plugged into a freshwater marina, you should install an ELCI to protect your self. The day is coming where some one will die of ESD and a boat owner will be sued or in the worst case charged for manslaughter.

I installed an ELCI but for the wrong reason. I wanted to be sure I didn’t trip a GFI dock. One day, I had a refrigerator die. Unknown to me it created a short between my neutral and ground. Fortunately the ELCI detected it and tripped. While I was confused for a bit when the ELCI wouldn’t reset after the refrigerator was unplugged, I eventually found the short in the refrigerator’s outlet socket.
 
tiltrider1 said:
If your boat spends any amount of time plugged into a freshwater marina, you should install an ELCI to protect your self. The day is coming where some one will die of ESD and a boat owner will be sued or in the worst case charged for manslaughter.

I installed an ELCI but for the wrong reason. I wanted to be sure I didn’t trip a GFI dock. One day, I had a refrigerator die. Unknown to me it created a short between my neutral and ground. Fortunately the ELCI detected it and tripped. While I was confused for a bit when the ELCI wouldn’t reset after the refrigerator was unplugged, I eventually found the short in the refrigerator’s outlet socket.
Click to expand...
The wires or the socket itself?
 
Sababa said:
I’d agree regarding many marinas but it’s super tempting when you are on a finger sticking out into the lake that is full of swimmers and paddle boarders just yards away on a hot summer day. How far away from a marina does one have to be to safely swim? Why isn’t it also a risk to swim off a boat that has an inverter or is running a generator in the open water?
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Because current flow is back to source. When the source is the boat itself, there is no path through the water required to return to source.
 
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