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Glad I found Sailnet
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Discussion Starter · #1 ·
Today's modern engines have microprocessors built-in, it seems. So when lightening strikes, or comes close enough to give your boat a strong Electro-Magnetic Pulse (EMP), do you have the kind of engine that will keep going? Or will it quit on you?

Not sure yet whether my Perkins Sabre diesel has a microprocessor or not, but it will be something I'll look into.
 

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Telstar 28
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Most of the smaller sailboat diesels are pretty primitive and many don't have much in the way of anything electronic on them. :)
 

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Telstar 28
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The lightning doesn't actually have to get to the engine to damage the engine, if the engine has any electronics on it.

The lightning is at 500,000+ volts or so... that means it can induce a voltage potential across any wires that are coming in or out of the engine... that voltage doesn't have to be very high to fry ICs... probably only in the range of 6-15 volts, depending on the ICs involved.
 

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Glad I found Sailnet
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Discussion Starter · #5 ·
The moving charge (electrons and/or protons, not here to argue this one) in the bolt creats a big magnetic field. That field induces current in any conductor nearby. So even a short wire will have a voltage across it. Like SD said, only a few volts will fry an IC.

I think I'm ok on this one. And I wonder why marine diesels would be made with any microporcessors at all, given that lightening strike er.. um.. potential.
 

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Tartan 27' owner
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I have my doubts as to whether Beneteau would outfit their sailboats with a microprocessor control unit/governor even if your engine is what, 65 HP? Why would they do that? It is not a car or a truck which stands a lot smaller chance of getting hit by lightning. There are plenty of dependable mechanical devices which will do the same thing (with a tiny degree of inaccuracy over a digital model) with half of the headaches.
You have the book on your engine so check it out. Does it have a 'brain' that would be vulnerable to EMP? I would doubt that on your 50' boat but I could be wrong.
I would almost worry more about lightning making a direct hit on your engine (somehow) and melting the cylinders or igniting your fuel tank. There are a lot of things you can protect yourself from but lightning is not the easiest thing to protect yourself from. There is a major debate of folks who say to ground everything (and they seem to get struck more often) and other folks who say to ground nothing and leave it all independent with a minimum of a grounding plate for the mast (located on the hull exterior). It is really more like alchemy then science at this point as people want to sell you on their ideas. Is it fun to sail through a lightning storm? No, but I have done it on an ungrounded MacGregor 26S. No one is a fan of lightning on the water except those that are trying to sell you some kind of protection from it (that is not really proven).
 

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Retired and happy
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As is often the case, I suspect that SD has the best handle on this one. The electromagnetic pulse associated with the freekin' big voltage of a lightning strike can fry almost anything electronic in the vicinity. All the small marine diesels I have ever been involved with have no electronics and are therefore safe from this effect. However, such a strike is likely to make toast out of any electronic gear one might have aboard, so expect little or no display from the blackened and smoking remains of your depth sounder, log, GPS, laptop, stereo sound system etc........:eek:

Stuart
 

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Discussion Starter · #8 ·
Agreed, it's a good reason to carry paper charts, and put the little x where you are periodically. I've heard of using a Faraday cage around equipment. I image that if you put a spare, handheld GPS in a metal box, it will still work after a lightening strike. But how many of us actually put a spare in such a box?
 

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Lots of power boats have electronic controls nowadays, and it could produce some interesting problems. The other usual engine location of electronics is in the ignition system, so your diesel is safe on both of those counts.
 

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How about electronic fuel injection? Not exactly sure how it works but I believe that on some modern engines, there's a microcomputer that regulates fuel flow.
 

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Telstar 28
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I keep a handheld GPS and a bunch of batteries for it in a cookie tin in the bridgedeck of my boat usually... handheld VHF there too when I remember to to put it back....
Agreed, it's a good reason to carry paper charts, and put the little x where you are periodically. I've heard of using a Faraday cage around equipment. I image that if you put a spare, handheld GPS in a metal box, it will still work after a lightening strike. But how many of us actually put a spare in such a box?
Most of the marine diesels I've worked with/on are using mechanical fuel injection pumps. Some of the fuel pumps are electric, and as such might be vulnerable to lightning, but none of sailboat marine diesels I've seen have electronic fuel injection. I've seen fuel injection on big rail diesels that are in some of the stinkpots I've worked on... but they're considerably more horsepower... like 700+ HP and the fuel injection requirements are considerably more precise, with far more cylinders to worry about.
How about electronic fuel injection? Not exactly sure how it works but I believe that on some modern engines, there's a microcomputer that regulates fuel flow.
 

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Can lightning strikes affect modern diesel engines?

Absolutely.

Here are two instances, gleaned from friends on the Waterway Net this morning.

1. While underway near Newport last year, the Spirit of South Carolina (South Carolina Maritime Foundation Spirit of South Carolina) lost both Cummins diesel engines due to a lightning strike; and

2. A former Commodore of the WaterWay Net, Bud, had his boat in a shed. The boat had a GM 8-71 diesel which was started by a nearby lightning strike, with him nowhere nearby!

Glad my 20-year old 4-108 doesn't have any microprocessors :)

Bill
 

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Bill-

The Cummins on the Spirit of South Carolina is a bit bigger than most of the boats on Sailnet would need...and probably requires EFI to run efficiently due to the sheer size of it.
 

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dog,

Yeah, and the 8-71 ain't no small puppy, either :)

But, the OP's general point is valid, i.e., that EMP from lightning can play havoc with just about anything having a microprocessor.

So, next time you're sailing in a severe lightning storm situation you can console yourself with the knowledge that that megayacht which waked you 10 minutes ago might just come to a screeching halt somewhere up ahead :)

Bill
 

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moderate?
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Agreed, it's a good reason to carry paper charts, and put the little x where you are periodically. I've heard of using a Faraday cage around equipment. I image that if you put a spare, handheld GPS in a metal box, it will still work after a lightening strike. But how many of us actually put a spare in such a box?
I do...two handhelds in the microwave oven along with a 36 pack of AA batteries whenever we were on passage. It is one of those things you just have to do for safety's sake.
Standard oven works great too.
 

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Agreed, it's a good reason to carry paper charts, and put the little x where you are periodically. I've heard of using a Faraday cage around equipment. I image that if you put a spare, handheld GPS in a metal box, it will still work after a lightening strike. But how many of us actually put a spare in such a box?
You already have a spare metal box, mine is made by Hillerange. Put your gear in the stove when lightning is near. I've done it before but haven't been hit by lightning. In theory it will work.
 

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Aspiring to be a Mexican
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I'm not sure if this relates at all, but driving towards the Miami Airport after a family vacation in the Keys last June, our rental car was struck by lightning. It was an '07 Subaru with plenty of electronics to be sure. The lightning struck right next to my head on the roof rack. It scared the everything out of me. I'm a trained race car driver and instructor and I take a lot of pride in staying calm in unexpected situations while driving, but I must admit that I flinched. I really flinched.
There was almost no damage to the rental car, a small pinhole burned through the paint on the roof rack and a 1/4" burn on the RF wheel. The car continued to operate normally.
The strangest part really was the sound. Obviously there was a large BANG, but immediately after that there was a crack! crack! crack! crack! crack! crack! crack! crack!
Exactly like the static electricity sound that you hear when you pull two sweaters apart after removing them from the dryer but 1000 times as loud.
I couldn't hear well out of my left ear for a couple of days and it's still not like it was before. That used to be my good ear!
 

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Aspiring to be a Mexican
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BTW, I heard a story about a small 20something foot centerboard sailboat gunkholing somewhere on the East Coast that was struck by lightning. The story goes like this, the keel stepped mast was struck and the lightning went straight down, burned a hole in the fiberglass, the mast sling shotted through the hole and down into the mud and the boat stopped dead in it's tracks, impaled on it's own stick.
Has anyone else heard this one or can anyone add any validity to the story?
 
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