LIGHTNING & WATER

[GordMay]

Originally Posted by hellosailor

In Florida the nooze stations have been saying THIRTY miles now. I don't know if that's to prod the slowpokes, or based on hits they've seen. But fifty...sheesh, FIFTY?!...

My caution was for lightning 10 MILES distant (50 Second delay between flash-boom).
Many others caution at 30 SECONDS Delay (6 Miles distant).

[Therapy]

Originally Posted by Alan Wheeler

Yeah well when the stuff starts going flash boom, I too wouldn't care about facts and fictions, I would get of the water quick as :-)

So, cruising is out?

[scotty]

i have seen lightning hit water, it made a circle of water about 10 feet across turn white. it was only white for about 2 seconds. it was also only about a 100 from shore. and about 150 feet from me when it happened

[Therapy]

Originally Posted by scotty

i have seen lightning hit water, it made a circle of water about 10 feet across turn white. it was only white for about 2 seconds. it was also only about a 100 from shore. and about 150 feet from me when it happened

...............

[cat man do]

I've had the boat hit while onboard, very scary and distressing at the time.

Dave

[scotty]

Originally Posted by Therapy

...............

i think the white came from a little bit of fine bubbles in the water, ie probably any imputurities being a point for the water to boil at. think of what happens when you use a microwave to boil water

i have had 3 close calls to lightning, that was one, two was talking on a plug in phone and the telephone pole out side less that 10 feet from me got hit ( i was in a trailer park, no not mine) third was at boyscout summer camp, a storm came thru. running back to the tents to close them up lightning hit a tree as we ran by, about 50 feet behind me.

as this point i think i am safe from pissing god off, he has missed me 3 times

[Therapy]

[amytom]

Was diving in a freshwater lake in TX (Lake Travis) when lightening struck the surface. I was about 40' down when I saw the bright flash and felt "tingly".

I used to work on Ion Implanters and when testing the high voltage we would routinely crank it up with the outer enclosure open until we feel our eyebrows pull away then shut it down.

I guess I'm pretty lucky and should have been a "Darwin Award" winner many times over.

[hellosailor]

"i think the white came from a little bit of fine bubbles in the water, ie probably any imputurities being a point for the water to boil at. "

Purity really won't matter. Throw a million volts into water, and some of it instantly superheats and flashes over into superheated steam, or plasma. That's going to release gas (hydrogen and oxygen even in pure water) and make frothy foam.

The gas from the foam might even be explosive--it has the right hydrogen/oxygen mix behind it.

[Alan Wheeler]

I really don't know, just guessing, so I am not arguing any point here. But my thought would be that no gas is produced. You would need to have an Anode and Cathode in the water and the different gases come of each respectively. I would say the water was boiling for split second.

[Wotname]

Nah, I'd say the water went white with fright - 'cause I would.

[SurfNRG]

While recently in Marsh Harbour in the Abacos/Bahamas we had a bolt a lightning hit nearby. It actually struck a Moorings catamaran (Cat House) and caused it to burn to the waterline. It was during the broadcast of the cruisersnet. Saw a bunch of people running frantically down the dock trying to move other boats out. The Moorings staff was on top of their game to make sure the loss was isolated to only that single boat. Makes you wonder why it chose that boat and not any of the others docked or anchored nearby. Highest mast height maybe a factor? We are not bonded/grounded except for our 55 ft high mast based VHF antenea. How legit is the theory that electricity takes the path of least resistance thus a grounded boat has a better chance of getting hit? I'm assuming the boat that was hit was plugged into shore power since it was at the dock thus having a solid ground.

[hellosailor]

Wheels, you're probably on the right track. Hydroxygen mix is produced by electrolysis. I suspect there is some, after all the "anode and cathode" here just mean "one place with lots of electrons and another that wants them" and that's what generates lightning--two different electrical potentials, just rather far apart.

But the foaming from superheating steam would be a heat effect...I guess making water vapor as it immediately cooled, rather than being gasses from electrical breakdown. Hmmm....probably a paper in there for some graduate student, on the localized effects of lightning claps on seawater. I'd hate to be the guy who had to run out in storms to collect that information.<G>

[Fishspearit]

Originally Posted by SurfNRG

Makes you wonder why it chose that boat and not any of the others docked or anchored nearby.

It was chosen because it was a catamaran Ha,Ha!

Notwithstanding their growing popularity, catamarans are more exposed to loss than monohulls. Experience indicates that the catamaran is more likely to sustain a lightning strike;

From the first post on this thread http://www.cruisersforum.com/forums/...stry-3190.html

Now we have concrete, verifiable, unambiguous proof that it's true! Avoid lightning, sail a monohull!

[SelkirkWind]

Originally Posted by SurfNRG

While recently in Marsh Harbour in the Abacos/Bahamas we had a bolt a lightning hit nearby. It actually struck a Moorings catamaran (Cat House) and caused it to burn to the waterline. It was during the broadcast of the cruisersnet. Saw a bunch of people running frantically down the dock trying to move other boats out. The Moorings staff was on top of their game to make sure the loss was isolated to only that single boat. Makes you wonder why it chose that boat and not any of the others docked or anchored nearby. Highest mast height maybe a factor? We are not bonded/grounded except for our 55 ft high mast based VHF antenea. How legit is the theory that electricity takes the path of least resistance thus a grounded boat has a better chance of getting hit? I'm assuming the boat that was hit was plugged into shore power since it was at the dock thus having a solid ground.

On the grounding issue, water is polar (particularly sea water). It creates a very good ground connection to the boat at the waterline as was previously mentioned. Your radios cannot get to this ground without a metal connection as the fiberglass is an insulator (except to very large current sources like lightning).

Having followed this discussion, here are the things I would do in serious lightening at sea:

In a Monohull or a Trimaran,
1.) Heave to if possible, and mechanically slave the rudder. (Note: even a close call can fry your electronics and thereby kill the autopilot)
2.) Get the crew below and forward (away from the mast and the rudder cables and most of the electrical system wiring in the stern. but aft of the forestay, or any cables leading aloft.) I am remembering that monohull cabins are at or below the waterline.
3.) Grab my fire extinguisher and keep it at hand.

In a Cat,
1.) same as 1.) above.
2.) the cat's hulls are shallow and at the waterline. The backstays are just behind the main beam. I would get the crew to lay on the hull floors forward of the mainbeam.
3.) As above, but one in each hull.

In a dock, like the picture included:
1.) I am sure I have a pressing need to be on shore in a bar.
2.) I should be drinking beer in that bar with the crew.
3.) I will be thinking about how I will enjoy shopping for a new boat my insurance's expense.
4.) More beer!

I look forward to your embellishment and comment on these guidelines.

Fairwinds,
Chip