Lightning at Sea!

Rannsachair · 31 July 2006, 20:59

I had my first experience of lightning at sea yesterday just East of Jura.

Blue skies quickly became black followed by hailstones, the wind got up and the wave height increased significantly then had a number of lighting strikes at the sea under a mile away from the boat!

I was somewhat concerned and tried to get out from under it as quick as I could.

I was conscious that when standing I was the highest point on the boat (had a low a-frame to fit in the garage and use a short vhf antenna) so despite the heavy sea's I tried to stay as low as I could. Should I have unplugged the electronics?

I do not intend to go out in lightning again, though if I am unlucky enough to be caught, just wondered what is best precautions to take - apart from the obvious: do not go out in lightning.

Ribald · 31 July 2006, 22:28

Anchor chain tied round the a-frame and dangle the anchor in the water - oh and electrics off.

dctucker · 01 August 2006, 03:39

Electrics on or off, they'll be fried if you're struck. Many boats have been struck in local harbors recently, many thousands of $$ in damage to electronics. Witinessed a boat struck maybe 300 meters away just Friday evening... massive shower of sparks, incredible crack of thunder. Closest I've ever been to a strike, frightening... Toasted electronics are not the big concern if YOU'RE on the boat at the time!

Best bet is to keep a weather eye, and head away from the storm cell, you should be able to navigate around them, I have in the past, in a 5 knot sailboat, a 35+ knot RIB should make it a bit easier.

Simon B · 01 August 2006, 08:25

The engine is grounded into the sea so the charge should find its way to earth through this, likely taking out the electrics also.

The fire service attended a "small" fire at our place recently and showed us a sample of phone cable that had been struck - There was no conductor left inside the insulation and the insulation had ruptured every 25-50mm (1" to 2") presumably to let the copper/ali vapour out.

jwalker · 01 August 2006, 10:10

Quote:

Originally Posted by Simon B

The engine is grounded into the sea so the charge should find its way to earth through this, likely taking out the electrics also.

I am under the impression the current runs from earth up to the clouds.

Electricity likes sharp edges and points.

codprawn · 01 August 2006, 16:59

Quote:

Originally Posted by jwalker

I am under the impression the current runs from earth up to the clouds.

Electricity likes sharp edges and points.

Usually but you can get + or - charges with lightning. Even worse you can get ligtning that switches between + and - so you don't know where the hell you are with it.

Used to be a bit of a passion of mine messing around with Tesla coils etc - with my new den I may just start experimenting again!!!

Limey Linda · 01 August 2006, 17:24

If you have ever experienced St. Elmo's fire in an electrical storm storm you will REALLY know how wierd storms can be. I did, only once, right in the middle of the Bermuda Triangle and it was accompanied by 270 degree sheet lighting going from cloud base to sea surface. Pucker cord got really tight. Flashes and blue streaks in the air inside the cabin of the boat and at the the same time trying to get and RDF heading on St. George, Bermuda. Will try not to do that again.
Regards, T.

Jonny Fuller · 01 August 2006, 22:45

Quote:

Originally Posted by dctucker

Electrics on or off, they'll be fried if you're struck.

Agreed.

I don't think people appreciate the shere amount of power in a lightning bolt.

The break/gap produced by a battery isolator or switch, will be little defence againt the might of a lightning bolt.

If it's managed to jump from clouds at ??? feet altitude to ground, what possible difference will a 5mm gap in a contactor make??

Nos4r2 · 02 August 2006, 00:40

Quote:

Originally Posted by Jonny Fuller

Agreed.

I don't think people appreciate the shere amount of power in a lightning bolt.

The break/gap produced by a battery isolator or switch, will be little defence againt the might of a lightning bolt.

If it's managed to jump from clouds at ??? feet altitude to ground, what possible difference will a 5mm gap in a contactor make??

Yep. One of my previous work's vans was struck in France in May. I wish I'd taken a photo of the electrics when it came back-they were exactly as described earlier.

Surprisingly, the guy managed to drive it back though he did have to get a bumpstart off the ferry. Diesels do have their advantages...

gtflash · 02 August 2006, 18:01

Quote:

Originally Posted by Jonny Fuller

Agreed.

I don't think people appreciate the shere amount of power in a lightning bolt.

great scott!! 1.21 gW

(name that film??)

jon is entirely right, switches do not stand a hope in hell. Once had the joy of trying to repair a stereo struck by lightning! Not a sausage left and non of the switches did a dicky bird!

Stormchild · 09 August 2006, 02:56

Watched a tele programme that reckoned a strike hit produces heat 4 times that of the surface of the sun.......forget the electronics, I doubt there'd be much left of the RIB!

EDDO · 11 August 2006, 16:31

A few years ago a neighbour of mine had his TV ariel struck. It went down the cable to his TV, fried it and jumped across from the UNPLUGED PLUG and earthed to the wall socket.
Another time when my son was a toddler , he was in the bath and ball lightening came through the open bathroom window. It hovered towards the bath and disapeared into the bath tap, no problem luckily.

Ed

Long time no see Kernow.

jyasaki · 11 August 2006, 21:32

Back to the Future.

Edit: Sorry; that was the name the film question.

gtflash · 14 August 2006, 17:12

Quote:

Originally Posted by jyasaki

Back to the Future.

Edit: Sorry; that was the name the film question.

yup

Seaharrier · 16 August 2006, 20:14

Saturday we went out for a drink from Zeebrugge to Vlissingen. When we came back the sky above Zeebrugge was totally black and filled with lightning’s. We called Portcontrol to ask them where the storm was going to. Force 6 and East. That was our direction. So we decided to go deeper into the Sea 15 miles away from the coastline. We had a splendid spectacle. While we were in the sun, it was raining cat's and dogs and the sky was filled with lightning’s above Zeebrugge. The storm stayed there for almost 1 hour.

Once home, we saw on the news that a windsurfer was hit by a lightning. Althouh his situation is critical, he is still alive...