Lightning Protection Scheme for the DIY'r ... ??

[DaleH]

As they say in Bahstin (read: Boston) ... whaddya think?

1) Lower all antennas and rods, but leave one METAL all-around light mast or one outrigger up (but shortened as short as possible)

2) Wrap chain tightly around the metal light mast or outrigger base and secure with a shackle

3) Drop the length of chain over the side of the cabin and have enough chain to reach 2' or more into the water

4) Put chain through HEAVY rubber rubing so it doesn't chafe anywhere on the cabin or hull

5) Add heavy lead 'sash' weight to end of chain so it'll stay in contact with the water even at speeds up to basic planing speeds

6) Perforate/punch 1/2" to 3/4" holes every few inches around the rubber tubing so it stay in contact with the water

Think it would be work?? OK ... who wants to test it :shock: ?

 

[mx beach guy]

Sound like it might work,Who knows it could save your life.

 

[grouperjim]

We'll get the Myth Busters to do the actual field testing. If anything left of the boat then we'll use the hull for the Racor clear plastic bowl experiment. Or better yet, lets do both at the same time.

All right, whose boat are we going to use? :mrgreen:

 

[Megabyte]

All right, whose boat are we going to use? :mrgreen:

Um... not mine. :shock:

 

[Wicho]

Hmmmmm

On paper... yes..
What do sailboats use for lightening???

William.

 

[goinsfishin]

Sailboats use a grounding system from the top of the mast down that is either embedded in the keel (best) or sometimes to the propshaft housing. Smaller boats might have a solid steel or brass "plug" thru hull.

Usually when they get hit it still fries all the electrics and wiring and if you are unlucky enough to be on-board or even close you can't hear right for a week.

Dale,
I had thoughts along the same lines, would probably work to an extent, would probably still fry your electric gadgets.
The only problem I see is you would need a very heavy weight to keep it down when on plane....would otherwise be riding up and beating on the hull (not good). Maybe not a device to be used when trying to outrun the storm, but after youve been caught and are riding it out.

 

[Porkchunker]

We'll get the Myth Busters to do the actual field testing. If anything left of the boat then we'll use the hull for the Racor clear plastic bowl experiment. Or better yet, lets do both at the same time.

All right, whose boat are we going to use? :mrgreen:

That would be a very interesting Myth Busters show. Lots of smoke and mirrors and myth about dodging lightening that they could debunk. ...now Thomas, how do we attract lightening?... :shock: :shock: :shock:

 

[andertonm]

Just a point of interest and it doesn't really answer the question, but - lightning rods are not made to conduct the lightning strike to ground. Before the lightning, an ionization path forms that allows the lightning to travel from point A to point B. A lightning rod causes the ionization path to discharge to ground, denying the lightning a path to strike. Apparently, the sharper the tip, the more effective the discharge action - that's why they're "pointy."

 

[Megabyte]

Speaking of lightning rods... here is a little history on the subject.

If you are ever in Annapolis and go to see the State House downtown, the lightning rod on top of the Capitol dome was made by Ben Franklin, and has served the building for 208 years. :shock:

http://www.msa.md.gov/msa/stagser/s1259 ... htrod.html

 

[FishStu]

I am no electrical or lightning expert--in fact I don't understand it at all--but what do you accomplish with the chain and sash weight that you don't already have with your metal motor in the water. Would seem to me that the motor grounds everything connected to it .

 

[goinsfishin]

I found a good basic article on lightning and boats, even though geared to sailboats it should clarify things and provide some guidance. here it is http://www.thomson.ece.ufl.edu/lightning/

 

[goinsfishin]

Fishtu's right, your motor is a ground point, however the lightning goes thru your whole system to find ground (water). The idea is to provide the shortest path to groung in order to avoid increased damages.

 

[DaleH]

Sailboats use a grounding system from the top of the mast down that is either embedded in the keel (best) or sometimes to the propshaft housing. Smaller boats might have a solid steel or brass "plug" thru hull.

Yeah, I know and some boats use the DynaPlate, but the DynaPlate or keel or propshaft housing all too often GETS BLOWN TO SMITHEREENS … leaving a huge hole in the hull :shock: !

The boat ‘survives’ the lightning strike only to sink where it was hit!

… what do you accomplish with the chain and sash weight that you don't already have with your metal motor in the water.

I want a DIRECT path to ground (water) without entering ‘me’ or any of my electronic components. Besides, no battery cable can withstand the amperage in a lightning bolt. Then again, the chain might not either … but it is easily replaceable.

Fishtu's right, your motor is a ground point, however the lightning goes thru your whole system to find ground (water). The idea is to provide the shortest path to ground in order to avoid increased damages.

Exactly!

FWIW I have sent my ‘idea’ to Boat/US’s Safety Foundation for analysis and also to the Lightning Lab @ NC State.

 

[Phil]

I have a problem with using the chain as a conductor. The chain links only make surface contact with each other and with rust and salt buildup it would make a very poor conductor. I also have reservations about running on plane with that setup.

If I were to make a quick & dirty setup, I’d buy a set of 25’ 4 guage jumper cables. Then mount an aluminum pipe or thick strip on the transom above the water line extending below the water line. During a TS, clip both leads to the outrigger and the aluminum tube/strip effectively making it a 2 guage conductor. This setup will allow you to run on plane without heavy metal swinging around. You can also use the jumper cable to jump start other boaters and it’s also cheaper than the chain.

 

[DaleH]

Then mount an aluminum pipe or thick strip on the transom above the water line extending below the water line ...

I agree the cables might be a far better choice than chain ... I will NOT attach anything to the hull ... as that is what will BLOWN OFF the hull and disintegrated 'if' a strike hits it :shock: !

I don't want no hole in my big girl ...

I actually thought of using heavy thick 4/0 battery cable but was concerned about corrosion. Sure, a galvy chain might not be the 'best' conductor, but it still would be a straight patch to ground. Hmmmmmmmmm, maybe a thick piece of flat copper or even just copper tubing ...

 

[Phil]

Just a few shallow 3/8" screws in the skin will do--no need to thru-bolt it. At worst, the lightning will rip the pipe off. Copper pipe would work if you like the greenish hue...Don't like all those "interminent" connections in the chain...