For those who depend upon electronics...

[Maine Sail]

While I still have my "DR skills" I have grown very comfortable with my electronics over the years. Last Wed I was hit by lightning and lost everything.

Even electronic devices, such as my hand held GPS, that were NOT EVEN CONNECTED, got fried. We could have easily been off sailing in the pea soup we have had for the last month or so and been left with nothing but paper and compass.

While I still keep a full DR kit with all the tools & charts my skills have admittedly become a little more rusty than I would like. I for one will be focusing on tuning up my skills cause even with multiple GPS devices on board they were wiped out in a split second..

This was not even a direct hit.... No depth, no speed, no gps, no radar, no VHF, no epirb, no nav lights, no compass light, no interior lights....


Good time to reflect on what you would do if you lost all these items in a split second while off cruising...

 

[Ross]

I have a Walker patent log that I can deploy. and a watch. Did the lightning mess with the magnetic compass?

 

[Interlude]

Same happened to us. Besides checking that all paper charts are on-board I now keep a hand held GPS, depth sounder and compass in a Faraday's cage. The magnetic compass is probably okay, but better to be cautious.

Regards
Stuart

Interlude
Sydney, Australia

 

[sailaway78]

DR skills

I agree that we should keep our DR skills sharp. Another thing I always do when far offshore is keep a reasonably close position in my head at all times, as well as a compass course to the closest landfall.

 

[Maine Sail]

I have a Walker patent log that I can deploy. and a watch. Did the lightning mess with the magnetic compass?

Hard to tell without more testing. I plan to have it professionally swung anyway as I have heard of strikes throwing off a compass...

 

[DougM]

Maine Sail:
Not that it makes any difference, I'm curious as to whetheryour boat was hooked up to shore power when it was zapped. I can see from your photos that it was a nasty hit.

I have heard of people keeping their portable electronics in the galley oven when not in use. I wonder if that really prevents damage from a strike.

 

[Maine Sail]

Maine Sail:
Not that it makes any difference, I'm curious as to whetheryour boat was hooked up to shore power when it was zapped. I can see from your photos that it was a nasty hit.

I have heard of people keeping their portable electronics in the galley oven when not in use. I wonder if that really prevents damage from a strike.

Doug,

She was on her mooring with all switches off. Lightning apparently came in through both electromagnetic pulse and the ground side of the system.

 

[All U Get]

While I still have my "DR skills" I have grown very comfortable with my electronics over the years. Last Wed I was hit by lightning and lost everything.

Even electronic devices, such as my hand held GPS, that were NOT EVEN CONNECTED, got fried. We could have easily been off sailing in the pea soup we have had for the last month or so and been left with nothing but paper and compass.

While I still keep a full DR kit with all the tools & charts my skills have admittedly become a little more rusty than I would like. I for one will be focusing on tuning up my skills cause even with multiple GPS devices on board they were wiped out in a split second..

This was not even a direct hit.... No depth, no speed, no gps, no radar, no VHF, no epirb, no nav lights, no compass light, no interior lights....


Good time to reflect on what you would do if you lost all these items in a split second while off cruising...

Hi MS,
Sorry to hear about your boat, but you're right about the DR skills. 1 degree error in a mile is around 100 feet so making a declination error around here of 15 degrees would take you 1500 feet off course. Traveling two miles and looking for a channel marker would be quite futile, especially in fog.
Hope your repairs go smoothly.
All U Get

 

[catsailor]

DR only works if you know where to start!

I make it a practice to write down bearing, speed, and lat/lon every 30 minutes if visability is bad. I have had GPS go out before and having a starting point was very nice.

I would much sooner keep my back-up GPS in a pot than in the microwave; the odds of it sliding to the back and getting nuked by an idiot (me) are too great.

 

[Mario G]

Our last outting is the 1st time we had anything but charts. lol my charts and the nav reading on my GPS doesn't seem to correlate.

 

[Ken13559]

Mainesail, after my 1st lightning damage some years back, I fitted zener diodes across all possible 12V leading to any electronics as well as Protech-4 charger output. Even had any problem since <fingers X>. My friend too fit the zener after his got hit. Then following year he got "hit" again while passing an oil rig during a lightning storm. He felt tinkling sensation from the standing riggings not once but twice although he didn't touch it. None of his electronics got fried that day. So maybe the zener diodes did help, may be it didn't, but no harm trying.

 

[kloudie1]

Yeah, I believe I'd have a tinkling time too ... as well as some other more smelly ones.. LOL !! ..
Seriously.. Ken, what type zener and how wired in?? Sounds interesting

 

[Ross]

I installed a surge suppressor on the main breaker panel in my house. We had small surge suppressors that we wired into the equipment that we built in industry. I wonder if they would help on a boat.
Down here on the Chesapeake there are shoals that extend for a half mile from the shoreline and there are other places where the depth goes from 30 feet to shoal like a cliff face. The current is often very strong in places during the flood and ebb of the tides. I carry a leadline for sounding but I think that in conditions of poor visibility I would heave-to and wait for conditions to improve.

 

[jibes138]

I hear the sparkies (EE's) around here talking about zener diodes that only allow current in one direction in terms of lightning protection on aerospace circuit cards. Seems like the right direction but we really need a good EE to tell us how to protect our grounding circuits from reverse current. If the mast is grounded to the keel or the engine and so are all your electronics you have an opportunity to charge up all the systems with high voltage, even though no current is flowing. Seems like that is a recipe for a spark plug where the voltage rises until it can jump the air gap to ground and create a spark. Since lightning has millions of volts, the gap is pretty big like a cloud to the ground.

 

[Witzend]

Zeners would not have prevented Maine's outcome. They are intended to conduct in the reverse direction at the breakdown E rating. The 12 volt systems in a boat can be protected from a malfunctioning regulator with these devices, but they would just fry in the a lightening strike. Besides the strike generally comes from the ground side.

 

[Snotter]

I hear the sparkies (EE's) around here talking about zener diodes that only allow current in one direction in terms of lightning protection on aerospace circuit cards. Seems like the right direction but we really need a good EE to tell us how to protect our grounding circuits from reverse current. If the mast is grounded to the keel or the engine and so are all your electronics you have an opportunity to charge up all the systems with high voltage, even though no current is flowing. Seems like that is a recipe for a spark plug where the voltage rises until it can jump the air gap to ground and create a spark. Since lightning has millions of volts, the gap is pretty big like a cloud to the ground.

I'm an EE but I am not an expert in lightening. I would like to hear what someone more knowledgeable has to say; but, I will give you my theory.

Lightening produces a big spike of electricity: instantly on; conducts for a while; then instantly off. (I say instantly but I know in terms of microseconds it ain't so.) This can be modeled with a step function. Mathematicaly transforming a step function from the time domain into the frequency domain results in many many frequency components, many of which are at very small wave lengths. When the wavelengths get to be on the order of the length of the circuits and wires in your electrical and electronical equipment, the circuits start acting like antennaes. (I don't like the word antannae.) When that happens the circuits start conducting large currents that are induced by the electro-magnetic waves resulting from the frequency components stemming from the lightening strike. The electronics go snap, crackle, and pop. If this theory is true then I would think diodes ain't going to work; however, I am a believer in faraday cages. Just my humble beliefs.

 

[Bob Poff]

Snotter is headed in the right direction.

The rise time on the induced voltage is fast enough that expressed in terms of frequency, it would be equivalent to VHF or lower end UHF. Zeners help, but avalance kind of slow.

You also get a double bang. The first as the field expands, and another as it collapses.

If I remember correctly the PolyPhasor telephone line protectors use a combination of MOVs, Zeners, and finally a gas tube. Each device intended to do it's thing at different points in the event time line. The MOV does it's best on the initial edge of the rise, then the zener avalanches trying to hold the voltage within reason, then finally gas tube ionizes and conducts the (relative) major part of the current to ground.

An MOV reacts quite fast. But will fail after repeated acts of bravery. Or even the first if hit hard enough. I've had cases after a hard strike where the MOV was shorted, its guts sprayed over the insides of the equipment. But only replacing the MOV had the equipment back and running.

 

[wonkodsane]

And even if the actual component electronics survived the induction caused by the magnetic field, it is unlikely that anything with firmware wouldn't get scrambled up good.

 

[kenn]

It seems as though lightning protection is still a dark art, primarily because it's too hard to test it... is this assumption correct? Has any person/institution developed a reliable simulation of a lightning strike, that would allow different methods to be tested?

 

[walt]

I have tested consumer electronics at work with a big ol lightning surge generator instrument. Its got a "microsecond range" rise and "millisecond range fall" time, 40 ohm output and goes up over 6K volts. You basically check functionality before, zap the part (usually both polarities), check functionality after. For example, we might directly drive an antenna input with this instrument or a DC voltage input - or drive the AC plug.

The zap level is usually something learned over time. The manufacture has some lightning failure rate they determine to be unacceptable and basically keep raising the zap level pass spec until they see less than this failure rate (on warranty returns).

FYI, here is a pretty good surge protection device for 12 volts. There is a 3K watt part which is better (this one is 1.5K watt) but for some reason I cant find it.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=1.5KE18AGOS-ND