Lightning While Docked

[Hydra]

Originally Posted by Bash

Anytime we're in an electrical storm I put one set of handhelds (GPS+VHF+PLB) in the oven, and another set in the microwave. I'm told that these appliances will function as a Faraday cage.

To protect electronics from lightning, I would rather put them in a watertight container and hang it over the side, in the water. *This* would surely work as a Faraday cage.

Alain

[Vasco]

Originally Posted by stacy

Our cat just got struck by lightning 3 days ago at the dock in Georgia. We are still determining the extent of the damage. Does any one know how to evaluate the rig for damage? Any thoughts on the incidence of rig damage from a strike?

After a direct lightning strike the rig should be pulled and inspected. Rig damage does not occur that often but what can happen is the headstay foil (if you have one) can have the sections welded together, also the headsail can be burnt not to mention all the wiring and internal halyards. Have a surveyor check everything, and I mean everything. It is amazing the things you find later, such as blown LED's on the panel. The boat should be hauled too to inspect the hull and thru hulls.

[stacy]

VASCO, Thanks for the info

[GordMay]

Originally Posted by Hydra

To protect electronics from lightning, I would rather put them in a watertight container and hang it over the side, in the water. *This* would surely work as a Faraday cage.
Alain

A submarine, deeply submerged in electrically conductive sea water, for example, is the most effective Faraday cage that can be constructed.

[Vasco]

Originally Posted by GordMay

A submarine, deeply submerged in electrically conductive sea water, for example, is the most effective Faraday cage that can be constructed.

How deep, Gord?

[Vasco]

stacy,

I forgot about the rudders. Check these closely, sometimes they have soaked up water and that can turn to steam and delaminate them or blow them apart. A surveyor should know all the things to check closely.

[GordMay]

Originally Posted by Vasco

How deep, Gord?

Mixed layer depth. About -150 Ft.

[hellosailor]

The watertight container might have mixed results--unless it was a metal container. Swimmers have been electrocuted by lightning striking water, the ground gradient is still large enough to fry whatever is in the water, and you'd still need the metal faraday cage to protect the contents. Except, now you expose them to flooding risk as well.

Better to keep them on the boat.

Gord, i suspect part of the protection that subs get is from staying at depth. As you go deeper, the discharge is also spreading wider, so the voltage differentials across whatever is in the water are going to be less at greateer depths.

And oif course, even a flimsy aircraft fuselage is good enough to make a fine faraday cage. The heavy pressure hull of a sub way exceeds that, no waterjacket required, is it?

[eyschulman]

At the dock in a storm try to tie up near but not too close to boats with taller masts-not 100% protection but pretty close.

[Bash]

Originally Posted by eyschulman

At the dock in a storm try to tie up near but not too close to boats with taller masts-not 100% protection but pretty close.

We just had a Hanse 54 move out of the marina, with a three-spreader mast that must have been at least 80' tall. When he left, I thought, "There goes my lightning rod."

[capcook]

I guess losing the electronics, as painful as that would be, is not the worst case... How often to you also get pinholes along your hull ? I guess that would total the boat, no ?

[Lively Wanderer]

I recently read a thread about fuel storage for extended cruising. The consensus seemed to be that the safest thing to do was lash the extra fuel containers down on deck.

Of course various metal objects were suggested as being available to lash the containers onto.

Well you know; lightning, metal, fuel…

Is this an irrational fear caused by my overactive imagination? Or is there a real potential for barbeque?

[cat man do]

Originally Posted by eyschulman

At the dock in a storm try to tie up near but not too close to boats with taller masts-not 100% protection but pretty close.

I have seen boats that have been hit by lightning in an marina that had many much taller masts close by.

[SailFastTri]

Originally Posted by Lively Wanderer

snip

Well you know; lightning, metal, fuel…

Is this an irrational fear caused by my overactive imagination? Or is there a real potential for barbeque?

Definitely irrational.

[marcro]

I did a course a few years ago run by an New Zealand guy working out of the university of Miami. He turned his findings into a commercial concern.

About MLP

I have used his expertese in the design of systems for superyachts and ships.
He is worth a read if you youre interested, he discovered some very interesting things!

However having said all of that I still reckon its a black art with lots of unknown!!!