Lightening flash, engine dead?

[Bene505]

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.

[sailingdog]

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

[mrwuffles]

Benes diesel is not small I must say. How would the electrical current get to the engine anyway wouldnt it just go down the mast and hopefully its grounded and dissipates right into the water? Try emailing them, I looked and it doesn't look like they run there engines with tons of computers, Perkins Sabre Marine Diesel Engine for Leisure Craft Applications

[sailingdog]

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.

[Bene505]

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.

[CalebD]

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).

[Leither]

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........

Stuart

[Bene505]

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?

[tweitz]

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.

[AdamLein]

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.