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John Smith
07-01-2009, 04:47 PM
Our weather these days seems to bring thunderstorms, complete with lightning almost daily.

Aside from running like hell for shelter, what's the best way to insure not getting hit by lightning. I'm guessing stowing the masts would be a good start.

Ian McColgin
07-01-2009, 05:23 PM
Thunderheads can range in altitude from remarkably low to over 60,000 feet high, but most seem to be 20,000 feet plus.

The electric discharge is the shortest electrical distance from the place in the cloud where the charge is building to the place on earth the complementary charge is.

It's true that certain tall hills and buildings on tall hills and trees on tall hills (height of hill often disguised by the rolling topography) get lots of strikes but those are anomolous conditions. At sea, the ability of a normal yacht's mast to "pull" the lightening is really limited. I know from personal anecdote of two boats hit by lightening and one of those was on shore.

It does make sense to have a path for lightening to follow and it makes sense to understand the gauss cone of relative safety, but really the sharp wind of a thundersquall is the hazard. Not the lightening.

I keep a length of old rigging cable to wrap on the leeward shrouds and toss over the side. That at least reduces the sense of electric crackle and eliminates St Elmo's fire. Never been hit so I don't know if it's as good a protection as the advocates claim.

Sail on & G'luck

rbgarr
07-01-2009, 05:24 PM
In the final analysis, lightning will hit whereever it damn well pleases and there's hardly a thing any of us can do about it.

You don't mention how much of a bother it is to lower your masts. Are we talking a small skiff or a job for a crane?

johnw
07-01-2009, 05:31 PM
My mast is an aluminum Snipe mast. When I see a thunderstorm approaching, I run for shore.

Bob Adams
07-01-2009, 05:37 PM
In the final analysis, lightning will hit where ever it damn well pleases and there's hardly a thing any of us can do about it.



Very true. A couple summers ago I was in the wheelhouse docked at the marina when a bolt ignored the outriggers on the sports fisher next to me, the aluminum mast of a sailboat 30 feet away but splintered the piling one of my bow lines was tied to :eek: Pretty spectacular.

John Smith
07-01-2009, 06:11 PM
In the final analysis, lightning will hit whereever it damn well pleases and there's hardly a thing any of us can do about it.

You don't mention how much of a bother it is to lower your masts. Are we talking a small skiff or a job for a crane?
15' wooden skiff, wooden masts. Easy to take down, now I've slotted the deck.

Only metal would be my drain plug. And, I guess, the outboard.

Ron Williamson
07-01-2009, 06:15 PM
We were at the public docks in Little Current last year when a thunderstorm rolled in and hit the windex of a charter sailboat, just down the dock.
It blew a pretty good hole(2"+)just above the waterline
Little Current has high hills to the south, radiotowers, transmission lines,a steel swing bridge and quite a few taller sailboat masts.
R

J. Dillon
07-01-2009, 06:36 PM
It's been a problem for a long time Here is a way they treated it aboard 17th century British men o War :

JD

"Prior to the early nineteenth century vessels carried copper chains which had to be hoisted to the lightning conductor on the masthead (if there was one fitted, and this was by no means widespread) whenever a storm appeared imminent; contact with the sea (the "earth") was made by a connexion outside the hull. One major problem with this system was the speed at which the chains could be hoisted, sometimes the ship was damaged before they were in position.

An improvement came when copper strips were run down each of the masts and through the hull to the ship's bottom, which in the case of many ships was now sheathed in the same metal. It is recorded, however, that in one man-o'-war the conductor actually passed through the powder magazine!

The French flagship 'L'Orient', which exploded dramatically at the Battle of the Nile, had a lightning conductor fitted to its masthead, which for a time stood as a trophy in the hall of Merton Place, the home Nelson shared with the Hamiltons. It is now in the collection of the National Maritime Museum at Greenwich. (The L'Orient explosion was not due to lightning.)

As an aside, the slang term for naval full dress trousers is 'lightning conductors', referring to the resplendent broad gold stripe down the seams."

Tom Galyen
07-01-2009, 09:02 PM
Psalm 18:7-15

The earth trembled and quaked,
and the foundations of the
mountains shook;
they trembled because he was angry.
Smoke rose from his nostrils;
consuming fire came from his
mouth,
burning coals blazed out of it.
He parted the heavens and came down;
dark clouds were under his feet.
He mounted the cherubim and flew;
he soared on the wings of the wind.
He made darkness his covering,
his canopy around him-
the dark rain clouds of the sky.
Out of the brightness of his
presence clouds advanced,
with hailstones and bolts of
lightning.
The LORD thundered from
heaven;
the voice of the Most High
resounded.
He shot his arrows and
scattered the enemies,
great bolts of lightning and routed
them.
The valleys of the sea were
exposed
and the foundations of the earth
laid bare
at your rebuke, O LORD,
at the blast of breath from your
nostrils.

Pugwash
07-01-2009, 09:26 PM
In cloud to ground lightning, it may seem that lightning strikes in a downward direction because of how quickly it happens, however, this is actually inaccurate.

By law, negative charges reside at the bottom of a storm cloud.
Positive charges reside at the top of a storm cloud.
If there is enough electrical energy within the storm cloud, a single negatively charged particle (electron) will emerge from the cloud and begin heading towards the ground. This is called a "stepped leader".

On the ground, positive charges begin building up below the stepped leader and since opposite charges attract each other, these positive charges begin heading up to meet the negative stepped leader.

When they connect to each other, a channel is established and more electrons begin flowing downward.

Next a "return stroke" of positive charges flow up this channel and create the bright flash we see as lightning. So yes, the flash we see as lightning goes from the ground up to the cloud.



Which means that you might not want to make yourself the positive ion closest to the cloud. (grounding or earthing yourself)

Milo Christensen
07-01-2009, 09:51 PM
I don't know. I used to regularly go windsurfing in thunderstorms just to get the adrenaline rush from the great everything airborne but the skeg you could get in the gusts. One day the metropark cops wanted to give me a ticket for "reckless endangerment of self."

Some of the moments in my life I've felt most totally alive is the times I've spent sailing on Lake Huron in thunderstorms. It's maybe a Nordic heritage thing, most folks don't seem to understand.

Pugwash
07-01-2009, 10:00 PM
Some of the moments in my life I've felt most totally alive is the times I've spent sailing on Lake Huron in thunderstorms. It's maybe a Nordic heritage thing, most folks don't seem to understand.

Lightning at sea is an "interesting" experience. If you're a commercial fisherman you don't have the luxury of heading for shore as fast as possible.

I'm glad I experienced it. Mind you, I'd prolly have a Billy Mays moment if I tried to haul a creel now.

2MeterTroll
07-01-2009, 10:13 PM
its not so bad the flopperstopper cable and chains take it right down to the water. course it frys the electric something bad. and does get inconvenient when you get a bit of a tingle in the down riggers from a close call.

Ian McColgin
07-01-2009, 10:21 PM
Fifteen people have been killed by lightening this year in the USA, most on shore which is to be expected as most people are on shore.

Today off Orleans on Cape one fisherman was killed by direct strike. The news reported as if the squall was sudden and unexpected which is just plain untrue. It was obvious. I was finishing up some sail repair since other boat yard commitments prevented us from the catboat caber toss and saw it about a half hour out, cleaned up and headed back to Hyannis.

The storm was impressively severe, bringing traffic on the Mid-Cape to a near standstill with suddenly deep run-off all over.

The TV news was scripted as if being in an aluminum skiff somehow increased the odds the boat would be struck. I don’t buy that. Nor do I think the notion that they were the highest - by what? five and a half feet -
mattered. The men (the other in the boat lived.) were clamming on the flats.

I’d have continued clamming secure in the notion that the storm would be over soon and who cares if you get a bit wet. Lightening will do what it will do. It’s well to take reasonable steps for any weather but sometimes what happens if bad luck, not bad judgment.

Condolences to the victim’s family.