Lightning

[Sumner]

.......... Heavy strap, keel bolts, 1 sq foot plate, it's all there.....Roger

Two disturbing facts...

..one is that a 1 sq. ft. plate is pretty much useless in fresh water. Things get a lot tougher protecting a boat in fresh water.

...the second is that I've read a couple places not so good things about lightning and water ballast boats vs a lead keel. The lighting can/could blow a hole in the bottom of our boats trying to get to ground since there is not a direct path from the mast to the keel as in a boat that had those connected via a strap and a keel boat. Also the water in the ballast tank is a conductor so it could try and jump from the mast to the ballast water (making a hole there) and then through the bottom of the ballast tank to the water (second hole). That isn't a pretty thought.

Here is an another link that I thought was good out of the ones I read....

http://www.marinelightning.com/ECE/SGEB17.html

..... If a person doesn't want to take the time to read it here is the part I felt was most important if you don't have good protection on your boat, which most of us don't......

Personal Safety
Consider the worst case scenario for a lightning strike to a sailboat - a small boat in fresh water. If the boat has been provided with a well-built protection system it is still an exceedingly hazardous situation. If lightning protection does not exist, the situation is life threatening. In both cases, the areas to avoid are close to the waterline and close to large metal fitting. In the unprotected boat, an additional -danger zone is beneath the mast or boom. Even in the unprotected boat, it is unwise to get in the water, as electrocution is highly probable if lightning strikes nearby. In fact, there is no safe place on an unprotected small sailboat, and in a protected boat only places of relative safety. There is, however, one place that is more hazardous than a small unprotected sailboat, that is a small unprotected boat without a mast. Every year there are multiple deaths of boaters in open boats caused by lightning strikes, but very few reports of sailors in sailboats killed by lightning.
The above general rules also apply to larger sailboats. These are generally safer, if protected, since it is possible to get away from the waterline and large metal objects, and yet still stay dry inside the cabin. As far as unharnessed electricity is concerned, a dry human body is much less attractive than a wet one

c ya,

Sum

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[bubba]

After thinking about it if we put our heavy copper grounding wires cliped to the shrouds on both sides and hang them in the water about a foot and half for wind waves and are moving we should disperse any electrical build up that attracts lightning. Last storm we were in the copper grounding wire ends that was in the salt water was really clean and shiny from some electrical transfurence in to the water.

Many years ago my wife sailed 20 ft daysailers 'Highlander boats' and one of them got struck by lightning and blew out both sides of the hull where the shrouds connected because they had no escape for the lightning to go to ground or water, so we keep the grounding wires under the king bed to use in lightning storms.

[Rick Westlake]

Didn't we stir this pot up last year, too?

I've taken the "massive grounding" approach to lightning protection; last year I bought and installed a SEYLA "Strikeshield" mast grounding system. It's a 1/0 gauge, tinned-copper grounding cable with a machined copper grounding electrode that drops into the water beside the boat; the upper end bolts to a thick copper mast plate, so it can be left below in good weather and quickly attached in worrisome weather.

Even if this isn't enough to prevent lightning damage, it will provide a path outside the hull for the discharge to follow. I hope never to test it with a lightning strike, but it may help me sleep better if there's a mutter of thunder around the anchorage.

[Russ]

There is, however, one place that is more hazardous than a small unprotected sailboat, that is a small unprotected boat without a mast. Every year there are multiple deaths of boaters in open boats caused by lightning strikes, but very few reports of sailors in sailboats killed by lightning.

This is what I was talking about.
You are probably safer inside your boat (not under the mast) than dinking into shore unprotected. The fact that so few sailboaters killed by lightning suggest that maybe the mast takes the strike instead of the occupants. If my boat gets a hole blowed in the bottom vs. me, I'm better off.


--Russ

[NiceAft]

Every year there are multiple deaths of boaters in open boats caused by lightning strikes, but very few reports of sailors in sailboats killed by lightning.

As much as I would like to believe that it is inherently safer to be in a sailboat during a lightning storm, I think that the ratio of power boats to sailboats may be a bigger reason. Who knows? Maybe because we know what the wind does to us in 30 kPH, we know to get the heck off the water when the sky gets dark, and Maria really picks up.

Ray

[Sumner]

....This is what I was talking about.
You are probably safer inside your boat (not under the mast) than dinking into shore unprotected.....--Russ

Russ the stern of the boat was under 100 feet from the shore with a stern line. It is quick to get into the dinghy off the stern ladder/platform and using the stern line to pull to shore we were there in under a minute . Believe me we might of been in a little danger for the minute, but once ashore and under some large boulders within 30 feet of the shore's edge we felt much safer there.

I agree if we would of been anchored out 1/4 mile and would of had to row or power to shore staying with the boat would of been better.

What is your guys take on Don Casey? I see him mentioned often and he has some thoughts on Static Dissipators and how to properly ground a boat (similar to the system Rick is using). He also has some suggestions on how to deal with fresh water vs. salt water.......

http://www.sailnet.com/forums/gear-main ... tions.html

I believe a system similar to Rick's wouldn't be that hard to make or that expensive and you could modify it like Casey suggested with longer copper (if you trust that) for fresh water.

c ya,

Sum

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[Catigale]

Interesting read Rick. Don knows his stuff and does cite a couple of studies that might be better reading than the paranoid stuff you tend to get from the guys trying to sell you protection gear.

I sail in two main venues - on anchor on Cape Cod (where I cant run away) and on the Hudson in NY, where tstorms come up quickly and you also usually cant get to a place on land. Ive chosen NOT to protect my boat as I am in the Rich school that unless i maintain such a system, I end up attracting lightning instead of dissipating a strike.

The one tip I do like in the link is to use flattened 1/2 inch Cu pipe rather than AWG 4 wire - this is probably a lot cheaper and has more charge carrying capacity than the wire solution, if I SWAG'd that right

[Hamin' X]

After thinking about it if we put our heavy copper grounding wires cliped to the shrouds on both sides and hang them in the water about a foot and half for wind waves and are moving we should disperse any electrical build up that attracts lightning. Last storm we were in the copper grounding wire ends that was in the salt water was really clean and shiny from some electrical transfurence in to the water.

Please do some research into what causes lightning. The charge on the boat is coming from the water and is trying to reach the clouds. It is generated by interaction between the clouds and the ground/water. When you trail wires in the water, you are only giving a better path for the charge that is coming from the ground and making yourself a better target for a strike. If you use this approach, it is imperative that you use a massive grounding system and that all metal objects are bonded together and connected to a common, low reactance ground system, because you will be more likey to be hit. This means that even where the shrouds connect to the mast and chain plates must be bonded, as well as the mast step. Bolts and pins will not do. Do not use multiple ground wires in the water. When attempting to control lightning, you must create a single, massive ground path. If your transom bracket for your outbaord is in the water, that is where you must creat your ground path.

The whole project is a tremendous undertaking and if not done right, will be worse than doing nothing. The total cost of protecting a Mac will quickly become a sizable percentage, if not out strip the value of most of our boats.

~Rich

[Catigale]

I

f your transom bracket for your outboard is in the water.

I dont think this is an 'if'. Every Mac I have seen has the motor mount in the water.

There sure seems to be a huge amount of bad info on this, but given Rich's professional experience grounding antennae, Im going with him on this one.

(corrected spelling errors)

[Russ]

Rich,
I too will rely on your experience and knowledge on this one. Since my Mac's outboard mount is in the water and I have no backstay, it seems like any attempt to ground my rigging would be next to impossible or would require a hundred pounds of cabling.

So how about some recommendations here. If caught in an electrical storm, what do you recommend?
Do you believe those dissipators are worth the hefty price tags?



--Russ

[Hamin' X]

RE the transom: This thread is in the Venture forum, so there might be some that are not in the water at all times.

As for the dissipators, make your own. You need not be concerned with super connections, as they are only going to carry micro-current loads. Material matters not, but I prefer SS, as it retains shape best. It need not be mounted at the top of the mast, just in open air.

Take a six inch piece of 1/4 inch, or better SS cable (the finer the strands, the better) and place it in a copper, brass, or bronze battery eye type terminal and crimp it tight. Fan out the wires and goop some liquid electrical tape (DO NOT USE SILCON CAULK) down in the center, to prevent most corrosion. Screw them onto the mast, or clamp them to the shrouds about half way up, on each side. Just make sure they do not interfere with sails, or running rigging.

As I said, we are not overly concerned about connection quality for electrical purposes, due to the low current. Anything under 10 Megohms (10 Million Ohms) is fine. What we should be worried about is mechanical strength.

Some folks have used the type of dissipator that aircraft use, but this is not really suitable for our purposes. Aircraft generate their own static charge via high speed air flow and must bleed it off into the same air. Our charge is conducted from the water to the boat and discharged into relatively calm air. Very little charge on a boat is developed by wind in the rigging.

I only bought my 26X in October of '09 and have not done this yet to my boat. As soon as I get the first cutting of hay up, I'll do so and post a how to in the Mac Mods section.

~Rich, from DEN again.

[bubba]

Rich I like your Idea of making your own.

[Catigale]

RE the transom: This thread is in the Venture forum, so there might be some that are not in the water at all times.

Another halyard whipping for me....

Ventures and transom mounted small outboard come out of the water

Powersailors X and M do not, in general.

Thanks for the catch.

[THE CUSCUS]

On a swing keel boat, could one connect the mast to the pivot bolt with a cable of sufficient size??? Surely the keel would be better than a scrap piece of metal thrown overboard?

[Catigale]

I suspect the metal keel on the Ventures would be fine....useless on my generation of powersailor of course (FG)

Im rethinking that. You need good connections on these systems or else the lightning reaches the point of resistance and then just blows a hole whereever it jumps - in this case the bottom of your boat.

How would you make sure your keelboat has a low IMP connection to your keel??

All this points back to Rich's post that to do this right costs MegaBucks.