LIGHTNING DETAILS -Risk Management

[Davidhoy]

Originally Posted by noelex 77

The brush head static charge dissipators seem to have only a very minor benefit in reducing the chance of a strike over simply grounding the mast.

I doubt the efficacy of those upside down toilet brushes too. I had one on my masthead when it got hit, and there were several other similarly tall masts nearby, yet mine was still the "chosen one". Like I said before, lightning is a strange beast - anyone who tells you they know how to beat it is tempting fate. But there are things we can do to reduce the damage caused, as you rightly pointed out.

Of course your gorgeous aluminium hull has no grounding issues at all ;-)

[Davidhoy]

Originally Posted by Cadence

It's a crap shoot! It would be nice if the answer could be found.

There's nothing you can do to eliminate the risk of being struck by lightning, but there are things you can do to ensure that no damage occurs. Take commercial aircraft as an example - they are regularly hit (once a year per plane, on average), but when did you last hear of any failures. However, the cost of making your boat "lightning-proof" would likely be beyond the reach of most cruisers.

[Cadence]

Originally Posted by Davidhoy

There's nothing you can do to eliminate the risk of being struck by lightning, but there are things you can do to ensure that no damage occurs. Take commercial aircraft as an example - they are regularly hit (once a year per plane, on average), but when did you last hear of any failures. However, the cost of making your boat "lightning-proof" would likely be beyond the reach of most cruisers.

They may have the advantage of no ground verses a boat? I wouldn't want to stand in water swinging a golf club or holding an umbrella. I strike without someplace to go isn't likely to have that great of an effect?

[GTom]

Originally Posted by ottow

Hard to know until tested ;-)
But probably a lot better than keeping the bag in a locker.

Mitigation is the way to go, I honestly do not believe one can protect a AWB yacht from lightning.
The bolt jumps 100s of meters in free air before striking, carrying millions of amps. Any protective device smaller than a main battle tank will simply fry...

Bonding wiring (of sufficient gauge) or wires from the stays/rigging to water may protect the hull and provide a better path for most of the energy.

To my knowledge metal boats do very fine, they act as a Faraday cage themselves if the deck is also metal . Maybe we should get a copper-mesh "boom-tent", both sides in the sea?

[noelex 77]

Originally Posted by Cadence

They may have the advantage of no ground verses a boat? I wouldn't want to stand in water swinging a golf club or holding an umbrella. I strike without someplace to go isn't likely to have that great of an effect?

A lightning strike that hits the mast will find its way to ground (water) whether the owner wants it to or not.

If you are in a yacht, due to its construction, the boat is effectively standing in the water and swinging a golf club above its head.

By providing a controlled path to ground the damage is minimised, although the enormous power of a severe strike can still cause significant problems. The main benefit of effective grounding is the risk of very severe problems (such as when energy punches a hole through the boat and the boat sinks) is eliminated, or at least very significantly reduced. The risk of more minor damage such as the loss of electronics is only slightly reduced with effective grounding.

[Olddan1943]

Originally Posted by Cadence

It's a crap shoot! It would be nice if the answer could be found.

Yup you nailed it.

I would like all new electronics but, I cant get hit by lightening. LOL

[RPZ]

So perhaps copper straps from the mast(s) above deck going over the sides into the water? Heavy copper cable from the steel rigging into the water?

[ArmyDaveNY]

I wonder if a kite or balloon trailing the boat by a hundred yards or so, grounded to the water but not connected to the boat by anything likely to conduct electricity would work to keep lightening from striking the boat. It's probably not very practical but it would make an interesting experiment.

Do you think I could get a government grant to study this? I think ten million and four years while I "experiment" in various places around the world would be sufficient.

[Cadence]

Originally Posted by noelex 77

A lightning strike that hits the mast will find its way to ground (water) whether the owner wants it to or not.

If you are in a yacht, due to its construction, the boat is effectively standing in the water and swinging a golf club above its head.

By providing a controlled path to ground the damage is minimised, although the enormous power of a severe strike can still cause significant problems. The main benefit of effective grounding is the risk of very severe problems (such as when energy punches a hole through the boat and the boat sinks) is eliminated, or at least very significantly reduced. The risk of more minor damage such as the loss of electronics is only slightly reduced with effective grounding.

I agree! I don't know why you quoted me? I was responding to aircraft being an entirely different animal as far a lightning strikes.

[Olddan1943]

Originally Posted by ArmyDaveNY

I wonder if a kite or balloon trailing the boat by a hundred yards or so, grounded to the water but not connected to the boat by anything likely to conduct electricity would work to keep lightening from striking the boat. It's probably not very practical but it would make an interesting experiment.

Do you think I could get a government grant to study this? I think ten million and four years while I "experiment" in various places around the world would be sufficient.

Ask the ding bat congress woman from Calif. She will get it for you.

[GTom]

Originally Posted by RPZ

So perhaps copper straps from the mast(s) above deck going over the sides into the water? Heavy copper cable from the steel rigging into the water?

A conclusion in a previous, lengthy topic was that lightnings prefer a high contact-area electrode in the water.

Originally Posted by ArmyDaveNY

I wonder if a kite or balloon trailing the boat by a hundred yards or so, grounded to the water but not connected to the boat by anything likely to conduct electricity would work to keep lightening from striking the boat. It's probably not very practical but it would make an interesting experiment.

In calm conditions interesting. Don't try it downwind...

Do you think I could get a government grant to study this? I think ten million and four years while I "experiment" in various places around the world would be sufficient.

Repulsing a hit is only possible if you change the electronic charge in the surrounding area, then the driving force of the strike is simply gone. The "only" problem is to do that you'll need more energy than that of a lightning...

[noelex 77]

Originally Posted by Cadence

I agree! I don't know why you quoted me? I was responding to aircraft being an entirely different animal as far a lightning strikes.

Sorry. Yes I agree aircraft (when flying) are far more removed from ground and therefore the effect of a lightning strike is not the same.

[Cyrus Safdari]

Originally Posted by RPZ

So perhaps copper straps from the mast(s) above deck going over the sides into the water? Heavy copper cable from the steel rigging into the water?

OK imagine the total electrical output of Hoover Dam, trying to go through a length copper cable...

[GTom]

Originally Posted by Cyrus Safdari

OK imagine the total electrical output of Hoover Dam, trying to go through a length copper cable...

It does in lightning rods... 0-1 gauge (40-60mm2) cables I think.

Originally Posted by Cadence

Hoover Dams output and lightning is apples and oranges.

True!

[Cadence]

Originally Posted by GTom

It does in lightning rods... 0-1 gauge (40-60mm2) cables I think.

Hoover Dams output and lightning is apples and oranges.