thunderstorms

[sailingdog]

Considering the very small surface area of the contact, the indirect route and the poor electrical conductivity of stainless steel, I believe this is more a psychological measure than anything that would affect the outcome of a lightning strike.

Originally Posted by Joesaila

I know I felt like a target...a marine elec tek told me of some who connect jumper cables to the backstays and the other end to a large 'dyna plate' and drop it overboard. My book says to get away from anything metal...what does that mean? Its like telling someone in a little jail cell to keep away from the bars...Go swiming I guess.

[TejasSailer]

"i plan on going out on the lake this weekend thunderstorms possible ..."

Here's a novel idea. Don't go out. That's what we do.

[southerncross31]

When lightning strikes wood it flash boils any moisture causing the wood to explode apart. Even if no metal is involved small amounts of moisture will act as a ground. I once saw a flagpole blow apart as a result of a lighting hit. It was old and probably had lots of water in it though.

[sailingdog]

Originally Posted by TejasSailer

Here's a novel idea. Don't go out. That's what we do.

Sometimes that's not an option... sometimes you're already out...and the thunderstorm is rude enough to come out to play...

[Boasun]

If you are that worried that much and don't have a lightening arrester system on your boat. Then using wire clips and attach battery jumper cables to your shrouds and hang them in the water.
Otherwise look up a good lightening rod system for your vessel and let us know what you found out. I think many people don't like looking into this subject for fear of what they may find.

You could have your In-laws hang onto the shrouds and trail their hands in the water. Or have your boss do this. Or that very rich relative also...LOL

[jimspafford]

took the boat out saturday reckon i got lucky only got caught in a few small showers was able to run from the bad storms was some thunder but no strikes on me got back to the dock after it was all over

[sailingdog]

A properly designed lightning grounding system will have a lightning rod at the top of the mast, a heavy conductor connecting the base of the mast to a heavy copper plate on the outside of the hull, using as straight a path as possible, to help reduce the chance of side flashes. If the mast is not aluminum, then a heavy copper wire should be used to connect the lightning rod to the copper plate in the hull. Wooden masts and carbon fiber masts do not conduct electricity well enough to be used. Carbon fiber masts also have the problem of internal delamination in the case of a lightning strike, caused by the heat generated as the electrical charge passes through the laminate's graphite components.

A 2" wide copper or bronze strip 2-4' long embedded in the hull of the boat is an excellent lightning grounding strip. If it has threaded studs that pass through the hull, it would work quite well, and have points to attach the grounding cables to. A minimum of four linear feet of exposed plate edge is generally thought to be the safe minimum for a lightning ground plate. IIRC, a brozne Dynaplate, often used as a radio ground which is sintered bronze, is not a safe lightning grounding plate, as the water that is trapped within the plate can vaporize during a lightning strike and cause the plate to "explode".

Ideally, the shrouds, stays, chainplates and stanchions should also be attached to the ground plate. This will effectively form a "Faraday Cage" that will help protect the boat's occupants. The "cone of protection" from such a system usually covers a 45˚ cone with the lightning rod's tip at its apex.

[Boasun]

A Horror story from my own Past: While working a 100' utility boat (steel hull) in the Gulf of Mexico. We were struck by lighting. It hit the SSB antenna. Blew out the Antenna coupler and the SSB before going through the radio's ground strap and out through the hull. The mate on watch, and only a couple of feet away, had to go change his now brown pants. :lol:
The Antenna had an air height of 49+ ft.
So think about Lighting safety out there and do install a good Lighting rod system for your sakes, if you can afford to. But the odds are about 58,000:1 to be struck by lighting and over 7,000,000:1 to win the lottery. Guess which will happen first!!??

[arbarnhart]

Originally Posted by TejasSailer

"i plan on going out on the lake this weekend thunderstorms possible ..."

Here's a novel idea. Don't go out. That's what we do.

If you live in the southern US, that pretty much means don't go most days from March until October. We are in a drought, but pretty much everyday's forecast include a chance of T-storms.

[camaraderie]

I have all wood spars, if I'm struck by lightening, am I looking at a blow out on my mast

Yeah...but you also have metal fittings and shrouds leading to the deck and those should have a path to ground as well. One thought would be to get a lightning rod type device up there and bonded to the metal work and shrouds at the top of the mast to minimize the chance of losing the spar.