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Old 18-10-2020, 17:42   #31
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Re: What if a lightning strike destroys instrumentation?

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Originally Posted by Jammer View Post
26 replies and no one has pointed out that pilotage and dead reckoning are primary skills that are more important than celestial navigation.

You use celestial navigation to find, say, Bermuda or the Marquesas if you lose all your electronics on a passage to one of those places.

You use pilotage and dead reckoning to find your way to the harbor at Luperon or to get through the Exumas on your way to someplace where you can get parts.

I understand what you are saying but when I started the thread I was thinking the lightning destroyed radar, depth-sounder, GPS navigation (and charts), radios and mobile telephone. That would leave you with binoculars, hand bearing compass, binnacle compass and possibly a timepiece. Anything else worthwhile?

As far as dead reckoning is concerned I become confused because I thought you'd lose that as well? (Aren't logs electronic?) But I'm no expert as I haven't even got my yacht in the water yet!

Maybe I should start reading Dr David Lewis's books?

Following his longstanding interest in old navigational methods used to explore and populate the Pacific, he employed similar techniques for the Tahiti-New Zealand leg of the Rehu Moana voyage without using a compass, sextant or marine chronometer
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Old 18-10-2020, 17:59   #32
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Re: What if a lightning strike destroys instrumentation?

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Originally Posted by coopec43 View Post
I understand what you are saying but when I started the thread I was thinking the lightning destroyed radar, depth-sounder, GPS navigation (and charts), radios and mobile telephone. That would leave you with binoculars, hand bearing compass, binnacle compass and possibly a timepiece. Anything else worthwhile?

As far as dead reckoning is concerned I become confused because I thought you'd lose that as well? But I'm no expert as I haven't even got my yacht in the water yet!


Maybe I should start reading Dr David Lewis's books?
Following his longstanding interest in old navigational methods used to explore and populate the Pacific, he employed similar techniques for the Tahiti-New Zealand leg of the Rehu Moana voyage without using a compass, sextant or marine chronometer
As I noted above, several GPS units aboard.

Also, paper charts, real ol’e fashioned compass, bearing compass, two depth devices, hand held lead line, AIS, who needs radar in a pinch?

We shut down all electronics in electric storms including disconnecting the mast main 40-pin connector. We run dead reckoning in a storm and hand steer. All electronics are disconnected both + and - leads. We have learned this through three strikes. We hav lost LED cabin lights, wiring, fuses, antennas, nav lights, winded, radios, stereo, circuit breakers, list is long. Two pole disconnects have so far protected every time.


Decided long ago a sextant was not in the plan.
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Old 19-10-2020, 12:15   #33
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What if a lightning strike destroys instrumentation?

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Originally Posted by Annie in WA View Post
Electronics failing during lightning strikes, how about LED lights they are all electronic and I don't put my cabin or nav lights in the oven. Any first hand experience from Florida or Panama sailors?


Head lamps and backup nav lights should be protected:
Inside a ZipLoc bag
AND
1. In the oven (if it has a glass door protection is greatly reduced)
2. In a metal ammo box
3. In a metal cash box.
4. In microwave.
5. ?????

Non-conductive enclosure isn’t part a of best practices for Faraday cage: ZipLoc

I prefer a steel box rather than aluminum or stainless because I feel it would be better dealing with a magnetic surge as well as the electrical spike but I haven’t been able to find good research either way.

Spare compass or hand bearing compass should be protected too.
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Old 21-10-2020, 06:42   #34
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Re: What if a lightning strike destroys instrumentation?

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Originally Posted by Adelie View Post
I prefer a steel box rather than aluminum or stainless because I feel it would be better dealing with a magnetic surge as well as the electrical spike but I haven’t been able to find good research either way.

The Faraday cage protects against the moving magnetic field. A thorough description of the phenomena requires a couple of years of college math, summary here for those inclined:


https://en.wikipedia.org/wiki/Mathem...magnetic_field


Non-math description here, easier to understand but less rigorous:


https://nationalmaglab.org/about/aro...e/faraday-cage


Quote:
Spare compass or hand bearing compass should be protected too.

I am skeptical as to whether this is necessary.
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