A Minor Case of EMP???

Last night at 1825, we had a very strong bolt of lightening come extremely close but just above and forward of our Flying Bridge. We suffered the loss of 1 RADAR system, 2 VHF-FM Radios, and the Intercom System.

The RADAR unit/Antenna was the higher of the 2 antennas. The VHF-FM radios antennas are 1 to Port and 1 to Stbd. The Intercom has a speaker mounted on the Flying Bridge forward. All system fuses are intact. No circuit breakers were tripped.

Yall's thoughts????

Most of the time when people use the term EMP, they mean a electromagnetic pulse with the potential to take out electronics over a wide area. Lightning strikes and near hits tend to damage electronics, especially radio systems connected to antennas, but over a very small area per strike.

What you describe certainly fits the description of a strong pulse of electromagnetic energy. I've seen IT systems killed by near-hits with lightning before. My sympathies, sir.

The fuses and circuit breakers failing to protect the equipment is curious. I'd be interested in knowing how the EM energy coupled to the equipment. I'd also be interested in which component of the radar failed.

Fuses and circuit breakers can do pretty well to protect against surges entering through the electrical supply. They don't necessarily do as well at protecting against surges entering through an antenna. It sounds like the intercom's wiring served as an inadvertent antenna.

More information can be read at http://www.arrl.org/lightning-protection .

If you have good lightning protection on your antennas, you may have less to repair or replace.

Those were my thoughts exactly concerning the Intercom system being fried.

I won't know about the RADAR components until we have an ET come onboard in Houston.

Add the TV satellite tracking antenna system to the list of fried electronics....

My best guess would be splash from the lightning strike. Same end effect as EMP, a large voltage drop over distance. It's the reason that cattle, with their front and rear hooves so far apart, do so poorly in lightning storms.

If your not using shielded cables and electronics enclosures, a near strike would fry anything in the immediate vicinity.

ET???? Did he... phone home?

Here's a weird twist: at noon today, the STBD VHF-FM radio came on line and is now working as designed. Any ideas as to what may have happened???

Incidents like only occur to people of impeccable good charactoer who are pure of heart - loyal, brave, clean, etc, etc

Nice idea but towboaters are not that pristine. I wish!

Well OK, you're pretty good for a towboater.....

An internal circuit breaker reset? A temperature sensor cooled enough to allow normal operation?

It must be something along those lines of thought....

Sorry to hear about your troubles. Just a reminder that fuses are notoriously "slow" in electrical terms. With advanced electronics the damage can be done well before any fuses blow. Breakers are better, just. One of the reasons the more capable surge protection schemes rely on a combination of things like MOVs and Diodes.

Another thought {rare} for the return of the radio is that caps that got overcharged coming back down normal operating range?

In any case, good luck with the tech and let us know what they find.

I'd expect overloaded caps to blow. A well made marine VHF rig may well have a thermal protection circuit that reset itself.

The TV Satellite System came back to life today.

The survivor radio quit transmitting today.

This is too weird. Maybe the lightning strike damaged one of the ship's cable assemblies? If you're dealing with a wonky junction or connector...

Wildman, I am not at all suprised by the random failures you are seeing after a "EMP" event. Todays electronics can fail, then "heal", only to fail again later.

I consider any electronics that have suffered such an event as unreliable and in need of replacement, especially if it is a life safety item.

I have attended many technical classes on static discharge and service work techniques that demonstrate the failure/heal cycle. Even improper touching of some components will cause changes to many components. Think about the problems in creating a static free workstation.

I strongly suggest that any equipment that suffered a failure and is now working be removed from service. Even competent repair technicians can not diagnose and prove safe equipment that has undergone a high static discharge event.

The survivor radio had a bad mic. It's working now with a new mic.

Nomad: it sounds like what you described!!!

The RADAR and the intercom system came back to life today. That leaves 1 VHF-FM Radio left O.O.C.