Lightning Arresotr For Solar Boat

Discussion in 'OnBoard Electronics & Controls' started by ashwinnaique, Sep 25, 2015.

  1. powerabout
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    powerabout Senior Member

    the boat with the tall mast was a hood in mast furler so enormous mast, 110'ish off the water.
    Tons of equipment up there
     
  2. BertKu
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    BertKu Senior Member

    Powerabout, Tall does not mean attractive for lightning to strike. It is a question whether it is electrical the shortest and lowest resistance for that particular area to be attractive to find its way for the lightning to that particular high mast. If that is difficult for somebody to understand, then that person will never understand what lightning is all about and how to deal with it.
    Bert.
     
  3. powerabout
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    powerabout Senior Member

    sure but when you look at this vessel you would think it would be a magnet yet it wasnt.
     
  4. BertKu
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    BertKu Senior Member

    You see that makes it so difficult to judge whether a boat needs lightning protection or could do without it. To play it safe, you do it in a controlled way, therefore knowing what the consequences are, should a strike find its way to the mast. Maybe a boat builder can find a low resistance downwards material combined with the stainless steel shackles and wires. Alternative to properly calculate what the Resistance is from top to water line, thereafter it is a matter of calculation. I know a lot of people will be skeptical, but they haven't done tests with 1 to 2 MegaVolt test sites. Bert
     
  5. powerabout
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    powerabout Senior Member

    Bert
    I've never seen it do same thing twice
    I have seen it go down a J24 mast then out the hull where there was moisture in the hull 5 or 6' from the mast, no burns on the mast but blew fist size holes in the hull and sunk it in 1 minute.
    One of my buddies did carbon mast tests with Hall spars in a lab with a massive van de graaf
    If the mast was sealed it must have run down the outside and no damage?
    If there was any exposed carbon it hit one fibre, then next and so on and turned the mast into a piece of floppy epoxy with no carbon left in it.
    I have seen one photo in a UK marina of a boat with spreaders and rigging on the deck and a down wind patch of black dust and mast completely gone.

    I think those furry sticks on top might do something as I know a few asian boats with those and no hits in 30 years?

    No Beach cats have ever been hit in our club but I have been whacked a few times by lightening risers when holding the back beam on the land in the rain and then the lightening hit the ground somewhere else.
    Also happened to me holding the stern stainless on a yacht standing on the dock then it hit the water a few hundred meters away. Its like touching a spark plug.
    Blew the mast B&G gear as normal as this boat was a magnet ( Mumm 30)
     
  6. BertKu
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    BertKu Senior Member

    That is correct, because none of them had the same environmental condition.
    I could have predicted that. if a measurement was taken on the electrical resistance from top to waterline. More than 0.1 (0.5 Ohm)? Nobody in the world can predict where the strike will find a better low resistance to get to the earth level.

    You still don't get it. What was the measured resistance over the full length. Not done? Then you will stumble on any impurities in the product and anything can happen. It is not controlled. The energy get stuck and will react like an wild animal to get rid of the obstruction.

    I am not surprised. The idiots did not do their calculations and measurements. If they had done so, they could have calculated what would have happened.
    You may have a point, it may generate an opposed static electricity of a few thousand volt static and thereby avoiding the lowest resistance path to earth. Good point. For a long time I have considered to do test with 100 to 200 KV ionizer and create a negative field, whereby the path to earth for the lightning is no longer attractive. Snack is, if it is the 10% of a electrical search from ground to cloud, I am blown up.
    No comment. Bert
     
  7. BertKu
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    BertKu Senior Member

    Our apologies for deviating from your topic. However I trust that it was interesting for you and your project. Some advice on the use of varistors, Transient Absorbs, gasarrestors products.

    1) First at all, you should not put a varistor over the plus and minus, but from plus to earth. If the minus is a solid low earth potential, then it is fine . You can then connect the varistor from plus to minus.

    2) Don't forget the tolerance. Let say + 20% / minus 10% (what is normal for a varistor) If your DC Voltage is 24 Volt and your varistor is a 30 Volt device. The Varistor could be 30 - 3 = 27 Volt. That would be your 1 mA threshold level. Should you have a charger which is a 28.8 Volt charger, you will clip the varistor by 1.8 Volt. The varistor will get warm or hot and it could no longer function properly anymore when a real surge pops up.

    3) If you use AC on board, bear in mind to take the fluctuation into account and also the factor 1.4 x the average voltage i.e. 230V AC = 325 Volt peak + 10 % negative tolerance = another 35 Volt. Your varistor should be at least a 400 Volt varistor. A 375 Volt varistor may clip the peak of the AC and it will slowly destroy the grains and become a short circuit. You will then say it is rubbish, it does not work. Also you place always the varistor from Life to Earth and not from Life to Neutral. Most people do that stupid thing and don't realize that neutral not always is really a low resistance to earth.

    Also you place a varistor from Neutral to Earth + from Life to Earth in a plug. Why would you say. I am then wasting a varistor. That is correct, but if you use an extension cord, there is no guarantee that the life has become neutral and if you use a varistor just from Life to neutral it is normally not very effective and people will say, it does not work, it is rubbish.

    4) If you use a lightning gas arrestor, for floating line equipment , like a telephone, it is better to use a lightning arrestor with one gas chamber and not two separate arrestors. We have done tests and because after the surge has ignited the chamber, both lines will be protected from the surge, while otherwise still a spike may be let through when using two separate arrestors. The middle part (connection) is then connected to earth.

    5) Transient absorption zenerdiode are the fastest devices. i.e. Pico Second reaction time, but can only handle low energy spikes.

    6) You should re-route the surge energy and not try to suppress it. By suppression the energy normally you get reactions like some forum members who are stating it does not work, but they forget that lightning energy is incredible high in energy and when directed to earth, normally a suppressor can handle the re-routed energy then absorbed energy.

    7) You calculate the surge protection device by taking the highest normal peak voltage to earth. By gas arrestors, please note that the arrestor stays short circuited if the DC voltage is not removed but must be lower than 30 - 35 Volt.
    i.e. a 450 Volt gas arrestor must have the 230 AC voltage brought to below 30 -35 volt to open up again. That is happening every 1/100 of a second (50 Hz)but you must realize that a gas arrestor is a short circuit and will trip your fuse. Normally it is not advisable to use gas lightning arrestor on AC. Except I use it from Life to earth and I don't mind if the earth leakage switch trips. It will protect the complete installation by a surge.

    Bert
     
    Last edited: Oct 1, 2015
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  8. BertKu
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    BertKu Senior Member

    Powerabout. It is actual interesting to see how a lightning strike moves observed at slow motion. The cloud creates friction against each other. Due to the friction, the electrons in the outer rings of the molecules get passed onto another cloud and where the electrons are moved out, the core is positive and the cloud becomes positive and the other cloud becomes very negative due to the additional electrons. Now the energy, the number of negative electrons are becoming so vast, that the energy, the negative electrons, start finding a path to earth (or another cloud sometimes to equalize) after a meter/yard it get stuck, the numbers build up and it moves side ways or whatever and find a lower resistance path. Now it arrives at your mast. It starts finding some stainless steel wires and it starts moving (normally at the outskirts of the material, not the center) downwards. suddenly it get stuck halfway at a shackle which is rusted or has grease or is a plastic obstruction. The negative electrons build up and tries to find another way, either by jumping through a better path in the air or your head, if you stand close to it, you will be cooked mince meat. A lightning strike is not pre-arranged, it is feeling its way through the air and in the process it jumps sideways, through wet wood , through anything what at that position is the best option for getting the negative electrons to earth. i.e. your water line.

    If you thus give a lightning strike a very low resistance way to get to the waterline, you can 100% predict that that lazy lightning strike is NOT jumping via your head or via the air for the fun to a higher resistance route. A lightning strike is not stupid, it takes the lowest resistance and if you provide that, by very low electrical resistance from top of the mast to the WATERLINE, not to the deck only. You can calculate what the scenario will be and can also predict what is going to happen to your boat and yourself.
    When I see a medical doctor, I am also not surprised if he predicts that I will get an heart attack, he measures my blood pressure or Cholesterol or place all the sensors on my body and measure. WHY ARE BOAT BUILDERS NOT MEASURING WHAT THE RESISTANCES ARE? AT LEAST THE CAN LIKE A DOCTOR PREDICT with reasonable certainty whether they have protected the boat well enough or badly. Bert
     
  9. powerabout
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    powerabout Senior Member

    Are you saying 1mm wire from masthead to water will make all lightening issues go away?
    I thought you need to measure resistance at a bazillion amps being pushed by a bazillion volts,
    which way does the big spark go, up or down?
    Do cats get hit less than mono's
     
  10. BertKu
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    BertKu Senior Member

    Powerabout, It is not the Voltage what is your problem, that can be a trillion Volt or 1 million Volt. The Voltage is the potential between A and B, it is the current what does the damage. The current creates a field around the wire. The magnetic field and the heat created by the HIGH friction of the HIGH resistance what does the damage. By having low electrical resistance the (in 1978 RSA) measured up to 40 current bursts of up to 50.000 Ampere each very short burst is no longer a big problem. Although with the more severe weather we are having, currents of up to 80.000 Ampere has been measured in the USA. But if you take 50 wires of 1 mm from top of mast to the waterline, you can safely say that for the few milliseconds, which each current bursts the wires will not heat so badly up that it will burn through, but 1 wire x 1 mm wire is not good enough. at least 40 - 50 mm2 in total over all your COPPER wires from top of the mast to the waterline is more advisable. And if copper is out, then thicker stainless steel wires, but then the mast is getting top heavy.
    You get a burst of 50.000 Ampere, e few micro/millisecond, then a pause then again a burst of a few thousand ampere , again a pause and then again a burst of up to 50.000 Ampere, until all negative electrons have moved from the cloud to earth (or visa versa) Because it is short bursts, a total of 10 mm = 10 mm x 10 mm x 0.785 x 100 - 600 Ampere/mm2 = +/- 50.000 Ampere. better to be spread over a number of downward wires. Yes, it will get hot, but because of the interval and total duration of the surge, the wires should survive. If you expect higher discharges from the clouds, you have to consider more copper or substantial more stainless steel. But measure your resistance from top of the mast to the waterline. Borrow a low resistance earth Ohm meter equipment from an electrician. They have to measure the earth resistance by law for every house installation. Buy him a beer and do some measuring
    90% , the surges comes from cloud to earth (down). 10 % from earth to cloud. (up)
    Sorry, I have now to attend to the EK and Porta problems (and that of myself)
    Bert
     
  11. powerabout
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    powerabout Senior Member

    Wow, I didnt know its pulsed current therefore it is possible to add a reasonable size conductor to earth so hence I get where your coming from you should then do a mega-ohm test

    I looked at a boat on the slipway once and with keel stepped mast that looked well earthed yet the lightning went down the shrouds into the chain plates and then out horizontal where each fore aft bulkhead bolt was which was 2 above the water and 2 below the water and made small holes so it leaked.
    Crew were in the cockpit when it happened leaning on the rails, they said it all got a bit tingly for a while
     
  12. BertKu
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    BertKu Senior Member

    No, you need to know what the resistance is. It has to be much lower then 0.5 Ohm , even less than 0.05 Ohm . You cannot measure this with a megaOhm tester. You are unable to measure less than 1 Ohm
    Speak to a local electrician.

    I can believe, that it gave some wwooowwh reaction.
    Bert
     
  13. BertKu
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    BertKu Senior Member

    Everybody will get a surprise when they do measure their resistance on their boat.
    Bert
     
  14. BertKu
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    BertKu Senior Member

    Oh, Powerabout. I forgot. Please use a platinum or paladium tip at the top of the mast to ensure a predicted entrance for the strike.
    Bert
     

  15. BertKu
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    BertKu Senior Member

    Powerabout, why don't you make and produce and do marketing a unit special for the yachting/boating industry. It is rather simple. A stable battery. A sensitive milliVolt meter. A bridge circuit. A number of spider wires which will have to be dumped in the sea at various places. A quality potentiometer for zero adjustment regulation, a very long wire for up to the top of all kinds of long tall masts, and that is all.
    One dumps the spider wires in the sea. You put the other mast wire also in the sea. You set the system to zero. You move the mast wire to the top, after the wire is cleaned and dried and then you do your measurements.
    Bert
     
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