Depth transducers in an electrical storm?

I’m currently anchored in the Bahamas and just had a severe squall pass by with lightning. I have 2 depth transducers and both would go offline periodically while the squall passed and then come back online shortly thereafter. It did this several times during the 30 min squall.

I’m between squalls now and both depth transducers are working fine. I thought the transducers work off sound waves. Does electrical activity cause transducers to go haywire? Anything to counter this effect?

Electrical pulses in the transducer excite the transducer to create the sound waves. When the sound waves bounce back the transducer picks up the sound waves and converts them into electrical impulses.

Are you operating the boat during a severe squall or just at anchor? It may just be a phenom that occurs during strong lighting storms and would not affect normal use. I would suggest turning off all electronics if you can during a lightning storm.

I had a boat's VHF antenna hit by lightning it took about 12" off of the antenna and damaged some other electronics, AIS system.

I was wondering due to the symptom. What is the frequency of lighting? I found this...

"When lightning strikes, it releases electromagnetic radiation in the VLF or Very Low Frequency band, which runs from 3 Hz to 30 kHz. "

Some transducers are in the 42-65kHz range. I am willing to bet the the lighting was confusing the transduces. It was seeing the lighting as a signal source and did not know how to handle it sending the unit off line.

Just a guess, but sounds good?

Thanks for the info, the electrical pulse must be throwing off the transducer. Not an option to turn all electronics off as I need to be able to go on immediate notice. Squall with 48 knot winds near rocky shoal so need my electronics to monitor situation.

One good way to protect your communication electronics in a lightning storm iso disconnect the antenna leads. Panel installations make this difficult. Pulling power leads is also recommended where possible. If not struck directly but subjected to near misses, the induced current in wiring can still be strong enough to damage electronics.

The lightning could be affecting the sounder module itself directly. Not much else you can do other than checking the negative wire connections and any chassis grounds.

rgano said:

One good way to protect your communication electronics in a lightning storm iso disconnect the antenna leads. Panel installations make this difficult. Pulling power leads is also recommended where possible. If not struck directly but subjected to near misses, the induced current in wiring can still be strong enough to damage electronics.

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While disconnecting your electronics may reduce risks from lightning strikes it’s not always prudent to go completely dark. I was anchored in 10 ft of water near a shoal and needed to monitor radar, depth, anchor alarm, etc. if my anchored dragged in the 48 knot wind I needed situational awareness.

You may lose the signal if the water gets too churned up due to wind and wave action.

Thanks for the reply but I seriously doubt it was due to turbulence, I’ve been in much worse sea state and didn’t lose depth. I followed up with Furuno and they confirmed in an electrical storm the transducers can be affected.

"Affected" is way better than zapped to death. Looks like yours are somehow self protecting.

Wdeertz said:

While disconnecting your electronics may reduce risks from lightning strikes it’s not always prudent to go completely dark. I was anchored in 10 ft of water near a shoal and needed to monitor radar, depth, anchor alarm, etc. if my anchored dragged in the 48 knot wind I needed situational awareness.

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If your dragging anchor in a 48 knot wind then you need a much larger anchor.

fgarriso said:

If your dragging anchor in a 48 knot wind then you need a much larger anchor.

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Thank you for the sage advise

rgano said:

One good way to protect your communication electronics in a lightning storm iso disconnect the antenna leads.

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Having a radio taken out by a lightning strike would suck. Anyone have a switch to conveniently disconnect antennas during such events? Getting in behind my radios would be an impediment to disconnecting the antennas during storms.

HeadedToTexas said:

Having a radio taken out by a lightning strike would suck. Anyone have a switch to conveniently disconnect antennas during such events? Getting in behind my radios would be an impediment to disconnecting the antennas during storms.

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One reason I also have a handheld radio in addition to my 2 Larger VHF radios. Might not have the range of the built in VHF radio with a 12’ antenna in the flybridge but would work in a pinch.