Lightning strikes

[davidfox]

Does anyone know what happens in a lightning strike. I returned from Holland 2 weeks ago and was caught in a horrendous thunder storm about 30miles off the dutch coast, we were reasonably prepared for winds etc prior to the storm hitting and we received over a period of an hour winds between 30-45 knots, building sea, torrential hail and rain all of which was mind focusing but the lightning and thunder all around was pretty scarey especially as i considered having a 13m aluminium lightning conductor stuck up in the air a certain receipe for a strike. I sat there in the cockpit soaking wet about 3m from the mast with my teeth clenched waiting for the bang, imagining being dismasted which in those conditions would not have been funny. Apart from going deaf what happens?

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[Spacewaist]

Check your electrickery and magnetics.

A lightning bolt is an electric current with a very large electro magnetic field. If you didnt protect your instruments they may have been fried.

Check everything electrickal - instruments, GPS and VHF. (My VHF TX channel was fried off Lisbon a few years ago during a storm in whcih I was not aware of actually being struck). Id also check the ships compass(es), particularly if it is a fluxgate type.

Presumably you havent sunk, so if you did ground a discharge it didnt go through the hull.

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[Richard_Woods]

I was hit by lightning last year when sailing on the east coast USA. It's a very common event there.

I won't say any more now, as PBO will shortly be publishing an article about my experiences. (I think it is due for the Oct issue). But I would just say that if you are planning to go ocean cruising you will need some form of protection

Best wishes, Richard Woods
www.sailingcatamarans.com

<hr width=100% size=1>Richard Woods of Woods Designs for quality sailing catamaran designs
www.sailingcatamarans.com

 

[RPC]

There is a whole section on lighting strikes and yachts on the following cruisers website

Have you visited the Blue Water Cruising Site <A target="_blank" HREF=http://www.onpassage.com>http://www.onpassage.com ?

 

[AndrewB]

Previous postings.

This is very much a FAQ, you may find 'topic exhaustion' among regulars who have posted their experiences before. But a search will throw up several accounts, as well as many different views on the best way of coping with the risk.

Check HERE, HERE for four previous longish threads.

Probably the best available research on this topic comes from the University of Florida, see for example <A target="_blank" HREF=http://www.thomson.ece.ufl.edu/lightning/SGEB17.html>HERE</A>.

 

[William_H]

In simplest terms protection from lightning is regarded as adequate by experts as having at least 2 square feet of conductor in the water connected by heavy wiring to the mast. Heavy being like welding cable or starter motor cable about 1cm diameter. the mast itself will conduct current reasonably well without too much damage but stainless steel, wet wood or hull is quite resistive so gets very hot with the high currents involved. you can burn the hull or fuse the stays if they are the only circuit to the water hence the need to bypass the current to the water with as low a resistance as possible. Trees tend to attract lightning because they conduct enough to get the leader going but when the main current hits the conductor the moisture in the wood boils and the tree explodes. You may see on church spires a copper conducter about 40mm wide 3 mm thick into the ground and this seems to be adequate although you would never know with your boat mast until you get hit what is adequate. regards will

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