Lightning

[Catigale]

..or anchor/moor next to a BIGGER sailboat

[Sumner]

......... I think kmclemore's idea is the best. Use the Mac's ability to move fast, and get yourself out of danger.............Roger

The problem is that this just isn't always possible. When you sail a lot of the lakes in the mountain states there aren't marinas and ramps or even homes close by. Let's say you are 20-40 miles up Lake Powell where do you go. We anchor out every night and some times these storms come up in the middle of the night. You will go to sleep .....

http://purplesagetradingpost.com/sumner ... -koot.html

... with clear sky's, no wind, and wake up 2-3 hours later and all h*ll has broken loose. You can be in the 10,000 Island area in Florida where you can count on afternoon showers almost daily at some times of the year. You are going to have to deal with lightning there.

We have a slow S under power, but I also think that having a faster X or M can maybe lull a person into a false sense of safety. How many times has the wind come up suddenly and the waves increase to the point that you can't motor at 10 to 20 mph and have to slow down and run at hull speed? If that becomes the case then you are going to have to deal with the situation just like we do.

I don't know what the answer is as lightning is never the same, but if you are out in situations like we are maybe at some point you need to do something to improve your chances of possible surviving a lightning strike. It is kind of like saying I'm not going to wear seat belts as I might get in a wreck and the car catches on fire and they break and I can't get out. Nothing will work in all situations, but there are some things that do seem to help.

We will probably try the plates over the side attached to cables that can be attached with a good electrical contact to the mast or shrouds. I'm going to keep reading and do something. We were out about 45 days last year and had to deal with lightning about 4-5 of those. Once we did go to shore and just sat in the rain under some boulders for a while.

c ya,

Sum

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[SkiDeep2001]

Another option, if you can't get out ot the way of an approaching thunderstorm, would be to drop your mast, so as to lessen the chance of a strike. I know it cuts into sailing time to lower/raise the mast, but hey, I can always use the practice. Just make sure you are done handling all the de-rigging chores before the storm gets within striking distance, which can be considerable. Lightning can strike an object up to ten miles away. If you hear thunder less than thirty seconds after witnessing a lightning strike, then you are unsafe. Rob

[Russ]

......... I think kmclemore's idea is the best. Use the Mac's ability to move fast, and get yourself out of danger.............Roger

The problem is that this just isn't always possible.

Yes. Especially when this is a Venture forum of non powersailors. Even power sailors have been caught in bad junk that they couldn't outrun or had no place to run to.

I'm going to keep reading and do something. We were out about 45 days last year and had to deal with lightning about 4-5 of those. Once we did go to shore and just sat in the rain under some boulders for a while.

It's a difficult subject and the more I read about it the more confusing it gets. What I've taken away from it is that if you can't ground your mast properly, you are better off not trying at all as you could create a bigger problem. And properly grounding the mast isn't easy and probably impossible with a trailerable sailboat like a Mac.

I'm concerned about your decision to go to shore during the storm. You may be putting yourself at a greater risk dinking into shore than staying on the boat. Lightning strikes can occur long before/after a T-Storm.

Interestingly what I've read is fewer people get struck by lightning on sailboats than power boats. That may be because masts provide some protection over open powerboats or there are simply more powerboats.

Last year a fisherman near our marina got hit and killed. Witnesses said he was casting his rod. Strange thing was the actual storm was much farther away.

The best advise I could find was stay away from metal and don't sit directly under the mast where a lightning bolt might seek ground. Oh yea, and pray.



--Russ

[bubba]

Dissipation array on top of mast.

Do these work when I have a VHF antana mounted right beside it extending up 3 ft or so ? Also I noticed the VHF antana has a plastic covered tip, does this help with lightning strikes or attract it ?

[Russ]

Dissipation array on top of mast.

Do these work when I have a VHF antana mounted right beside it extending up 3 ft or so ? Also I noticed the VHF antana has a plastic covered tip, does this help with lightning strikes or attract it ?

Best answered by Hammin' X:
It is designed to dissipate the charge that develops on your mast, not a lightning strike. It is this charge that attracts the lightning and initiates the strike.

So it's my understanding that it "brushes" the air to dissipate the charge, therefore I don't believe an antenna would interfere with its functionality.

I'm not a lightning expert, but I really doubt the plastic tip does anything more than keep you from poking your eye out when installing it.


--Russ

[rwmiller56]

Sumner wrote: We will probably try the plates over the side attached to cables that can be attached with a good electrical contact to the mast or shrouds. I'm going to keep reading and do something.

That sounds like a good idea. Anything to divert the strike energy to ground (water), and keep it from arcing, like under the mast.

I feel fortunate that I do most of my sailing in the SF Bay Area, where we rarely if ever have any lightning strikes near the bay. They have been know to occur, though, at the higher elevations of the bay area. I will pay attention to this when sailing at higher elevations, like Lake Tahoe.

Roger

[Catigale]

IVe been caught in lightning a couple of times, including twice under power.

I ended up on the balls of my feet in the cockpit, avoiding touching metal parts.

With my Tillerpilot, I could even go below and pilot from below decks - a strike would definitely fry it, but at least I would survive

[Hamin' X]

Let me try and answer some questions and address some misconceptions. First, the VHF antenna. The plastic tip serves several purposes. Underneath the plastic, the antenna rod is cut square and this can cause coronal discharge, creating static in the receiver. Coronal discharge occurs when surface charges build up on an object and discharge into the atmosphere. Bad for radio reception. The cap also prevents puncture wounds and serves as a visual clue. On some antennas there is a crimped on ball, or teardrop end. Same function.

The dissipators do the same thing for the entire boat, but in reverse. Each one of the wire ends is a square cut, with a sharp edge. These encourage the discharge of the charge that builds up on the boat and rigging. Please note: dissipators do not need to be metal, or even what you consider to be a conductor. The charge that they are conducting is a surface charge that will flow on the outside of most objects. Ever wonder why the old dead snag is the one that gets struck in the middle of a healthy forest? The leaves and needles of the live trees are acting as dissipators. The old dead snag is radiating the charge from just a few points. Fewer points, same amount of charge. It's like waving a flag at the clouds and saying, "Here I am, kick me".

Now you are thinking, "Why don't I just throw some wires into the water and drain off the charge that way?" Sorry, the charge is coming from the water and crawling up the outside of your hull to start with. The wires will just give the charge an easier path and wave the flag at the clouds harder. "Well, the wires will conduct the lightning strike to the water and all will be well, right?" Wrong, The wires will melt, or a connection to the wires will fail. Now where will the high voltage, mega-amperage electricity that you invited aboard go? Any where it wants to and you will be dealing with molten metal from the failed connections and wires, as well. Most people have neither the funds, equipment, nor the technical ability to install a proper grounding system. Better to do nothing, than to invite disaster. Personally, I prefer the dissipator method, but I'm sure that there is someone out there that will take your money for a suspect ground system. I have even seen some folks that use a ground system in conjunction with the dissipators. Think about it and you will find it as funny as I do.

~Rich

[Russ]

Good stuff Rich,

I now understand how those dissipators work.

From what I've read, you are spot on about poorly grounding. Hanging an inadequate ground over the side (jumper cables) will provide a path that will result in molten jumper cables melting a hole in the side of your boat.

The dissipator is tempting, but at $ 123 per unit is a little pricey. The next one up is over $300 for what looks like a wire brush.


--Russ

[NiceAft]

The best protection is getting off the water before the storm gets to you

As to the speed of a Mac getting you out of trouble i.e.

Use the Mac's ability to move fast, and get yourself out of danger.

, you will have a false sense of security. The same false security of believing jumper cables over the side will work.

A few years ago I was motoring back from the northern most part of Lake George, and a storm (a real black sky) approached over the mountains from the stern. I tried to outrun it, but my Honda 50hp was not up to the task. I needed to travel about 15 miles to the nearest public dock, and a 50hp motor just won't outrace a fierce storm running the same way as you. As the storm caught up to us, I quickly pulled around an island with tall trees, and anchored as close to the shoreline as possible. The wind was blowing hard as I let out about 200' of line (so much for the protection of tall trees), and the admiral and I then went below and closed the hatch to ride out the storm. It was a scary 10 minutes.

Not as scary as the time we were in our Phantom (think SunFish) when the same thing happened as we were sailing a lake in Saugerties N.Y. There was no below to go to We just sailed to shore as the lightning flashed all around us That, was scary


Ray

[flynfol]

Years ago I was throwing engine covers on an old cargo plane (Beech 18) during my "paying the dues part of my career". There was a fast approaching thunderstorm which struck a light pole about 50 yards away. The induced voltage in the aluminum plane sitting on rubber tires passed from my forearm which was touching the plane,to the ground. Needless to say, it was a heck of a shock, way more than the auto sparkplug ignition variety. As you suspect, the cover was left to blow away in the wind.

Years later, over the Gulf of Mexico, I was at 39000' well away (at least 20 miles) from thunderstorms, when the plane lit up inside like being in a flourescent tube. The resultant bang and loss of all comms and nav equipment and frantic passengers talking of fireballs rolling up and down the isle then out over the wings made for a long trip. Luckily we carried a handheld nav/comm (KX99 for you techies) that allowed us to go feet dry at MSY. We figured the strike hit the tail nav light which had 7 separate 1/2" dia holes, including one through the glass lens. There were 300 or so exit holes the size of a pinhead over the entire plane, including in the wiring inside the fuel tanks for the capacitance fuel indicating system
Nobody was shocked or hurt, no fires. We were leaving a contrail that day, and maybe we "bridged" the gap between to high potentials.

Lightning is some crazy stuff, and being static electricity, doesn't act like the stuff we play with.

Then there was this pelican at night after takeoff over Brownsville , Texas one night...........................

J

[DaveB]

I live and Sail SW. Florida, Nations Capital of the World for Lighting . In 45 years of Sailing East Coast down to S. America and 22 years sailing all Florida I only had one branch of Lighting that trashed (killed the depth computer,no fire) my depth sounder in Pensicola during Beer Cruise 2007.
Way I look at it is you won't know it hit you in a direct hit, other is take out all your electronics (get a lead liner box and put electronics in it during Lighting) or disconnect wireing to them as a much less solution.
The branches off these Lighting strikes is usually the kill of electronics.
Dave

Is there a danger of being in the sailboat in a lightning storm?

[Sumner]

Just to make one thing clear. If I do install a grounding system it WON'T BE JUMPER CABLES ATTACHED TO A METAL PLATE. It would be in accordance with the following....

http://www.kp44.org/LightningProtection ... ndards.php

I'll leave the jumper cables in the Suburban,

Sum

[rwmiller56]

Good post, Sumner.
ABYC should know what they're talking about. Heavy strap, keel bolts, 1 sq foot plate, it's all there.

Roger