newbie lightning protection?

justsomeguy · Jun 5, 2016

There is no consensus. There's plenty in the archives on "lightening" too.

woodster · Jun 5, 2016

the only people i have ever know that seem to have protection from lighting is the Warlocks.....

JamesG161 · Jun 5, 2016

justsomeguy said:
There is no consensus.

You never need a consensus on a SCIENCE!
However several types of sciences involved, thus the confusion.
List in order of your ability to control them...
1) Electrical (flow of electrons)
2) Math (statistics)
3) Religion

If you combine all 3 you can reduce your chances of being a target.
In a nutshell...
1) Ground your boat and Isolate yourself
2) Buy Insurance
3) Pray it doesn't hit you

The most concise discussion I have seen for science 1) is attached.

@woodster I admit Magic may be in play too, but lightning is not a reason for avoiding showering for 3 weeks.

Good Avoidance...
Jim...

PS: Someone posted these pages from this great book by Nigel Calder.
https://www.amazon.ca/Boatowners-Mechanical-Electrical-Manual-Essential/dp/0071432388

justsomeguy · Jun 5, 2016

JamesG161 said:
1) Ground your boat and Isolate yourself
2) Buy Insurance
3) Pray it doesn't hit you

All good things, JamesG161.
I commend rpludwig for searching the archives. He'd already listed the basics for minimizing the risks in his OP, which amounts to the "consensus" arrived at numerous times in these fora.

Kermit · Jun 5, 2016

justsomeguy said:
... which amounts to the "consensus" arrived at numerous times in these fora.

But did we ever come to a consensus on the plural of "forum?"

justsomeguy · Jun 5, 2016

Kermit said:
But did we ever come to a consensus on the plural of "forum?"

woodster · Jun 5, 2016

JamesG161 said:
@woodster I admit Magic may be in play too, but lightning is not a reason for avoiding showering for 3 weeks.

this is not southern california ....we do have rain here ya know

JamesG161 · Jun 5, 2016

Kermit said:
But did we ever come to a consensus on the plural of "forum?"

After 2 years of high school Latin... Singular nouns end in "US/UM" Plurals end in "AE" ( pronounced aye).
Thus....
Status Statae
Datum Datae
Octopus Octopae
Porpus Porpae

Forum Forae

So don't be caught among the Group of ANAE!

justsomeguy said:
There's plenty in the archives on too.

Yeah I hate my spell checker for changing mistyped LIGHTNING to LIGHTENING

@rpludwig All seriousness aside...
My boat has the ABYC standard E4 lightning protection, but I have a 7200 lb grounding lead keel, and my mast and standing rigging is 4 gauge wire grounded to it. I also have a static charge dissipater on top of my 67' mast.

You can web search it.
http://www.kp44.org/ftp/UnderstandingLightningProtection.pdf

However there is no known surface of the earth Prevention.
Jim...

CloudDiver · Jun 5, 2016

To give you a simple answer... For any small boat, yes, the first line of defense is to try to stay out of inclement weather. Beyond that, if you think you might get caught off guard; The most cost effective lightning protection for small boats is to carry a long set of automotive jumper cables. You can split the set so you have two cables... Attach the gator clamp to your backstay, strip the other end so you have maybe a foot or more of bare wire and throw it over transom into the water. If you do get struck it gives the bolt a path to the water and hopefully not through your hull.

Kermit · Jun 5, 2016

rpludwig said:
you guys are a hoot!...
...I will stow some jumper cablae!

I nearly spewed!

CaptDon01 · Jun 5, 2016

Lightning is looking for a path to ground.....improve the grounding on your boat, and you'll help ease lightnings search for another path to ground.....

Best solution? Good insurance and a low deductible.

Don

Bill Roosa · Jun 5, 2016

But insurance will not get you back to shore after a strike so........
Common practice in tall buildings that get hit numerous time a year is to take the lightning to ground by a dedicated lighting circuit that is OUTSIDE the building. Nobody in the construction industry would even consider running the lightning circuit inside the building, that is a great way to get your occupants dead.
What this means for boats is disconnect the mast to keel circuit and run jumper cable size wires from the four stays over the side and into the water. I have a set of jumper cables that I cut in half and separated to give 4 cables with clamps on one end. strip the insulation off enough of the non clamp end to have bear wire entering the water, not insulated wire , bear wire. Deploy at the first sign of lightning.

walt · Jun 5, 2016

I think its interesting to look at how a capacitor works when you consider the effects of grounding or not, or if you keel has direct metal connected to the water or if the cable has the insulation stripped off in the last post

A capacitor has two plates with an insulater in the middle. When a charge (for example electrons) is put on the plates, a voltage develops across the plates. The voltage across a capacitor is directly proportional to the charge in the capacitor. Add charge and the voltage increases proportionally.

In the case of the boat, an ungrounded mast forms one plate of the capacitor and the water the other plate. The insulator is mostly air plus a thin layer of fiberglass. Or if a wire is connected to the mast and is hanging in the water and its insulated, then the inner wire is one plate of the capacitor and the water is the other plate and the cable coating is the insulator.

In the case of an ungrounded mast, if lightning attaches to the mast, a huge amount of charge flows into the mast. Guess what happens to the voltage of the capacitor from the bottom of the mast to the water surface.. all that huge amount of charge creates a proportional huge amount of voltage.

As we know.. air is ionized during a lightning strike and all that charge creating all that voltage on our capacitor easily ionizes air and an ionized flash or air forms, the capacitor breaks down and all that charge flows to ground.

Same thing happens through the wire insulator. All that charge very easily creates such a high voltge across the insulator that it breaks down.

Whatever models you have that say grounding matters, please let us know what they are. Or if its based on some real statisitics also let us know. If its that you have to have a ground to get your cabin lights to work.. you might not have the right model.

Grounding or not may have a small influence on your chances of receiving a strike but its probably way less significant compared to the fact that you have a significant long vertical conductor (your mast) which makes a nice electric field short cut for lighting.

walt · Jun 5, 2016

I also have a static charge dissipater on top of my 67' mast.

Curious as to why? (hopefully without using analogies to explain since they are best used to mislead and may have nothing at all to do with the actual problem but sound good).

walt · Jun 5, 2016

By the way, the only argument I have here is regarding if grounding influences your chances of a strike. I think grounding is a good thing.

I used to hear an argument that you should not do any sort of grounding if you are not prepared to do it completely right. The argument was that inadequate grounding was going to invite a side flash..

But in the case of an ungrounded sailboat, you already have 100% chance of a side flash if you are not grounded. So how can adding anything increase the odds over 100%.. Uh.. well 100% is 100%, you cant. Adding any sort of grounding like the cable from the mast to the water adds an extra path for the lighting to take. If you dont do a good job with your ground path, you may not remove enough charge to prevent the side flash.. but any sort of additional path might reduce the strength of the side flash. And if you do a good enough job with your known path for the lightning, you may out compete with ionized air and prevent a side flash. Its about the odds.. You start with 100% chance of a side flash doing nothing, additional grounding paths start to reduce the odds. You may not get the odds all the way to zero but there also isnt really any evidence that you will do something bad like attract lightning by adding grounding.

Edit.. I just noticed this is in the C22 forum. With the way the post show up when I go to this site, I often dont notice which forum they are posted in.. Sorry about that..

justsomeguy · Jun 5, 2016

Maybe there should be a "sticky" post on lightning strike risk mitigation somewhere on these forums?

newbie lightning protection?

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