Operating the Sonar When the Transducer is Out of the Water

Geez, after 33 years of operating various fishing boats, I only now learned that a sonar unit and transducer could be damaged by operating the sonar when the transducer is out of the water as when attached to the trolling motor when stowed while moving from spot to spot. From another message board…

“Most manfacturers caution against operating the transducer when not in the water. Think of the transducer like the head or skin on a drum. When struck it emits sound. The transducer is designed to be operated while its “drum” is in water, which has a dampening effect. When operated in air there is no dampening effect and the “drum” could be damaged by being struck too hard by the electrical pulse which excites the piezoelectric element of the transducer.”

Apparently, the sonar will maximize power to the unit when the transducer is in air, trying to get a signal. This powerful air pinging can damage the internal circuitry of the head unit as well as the transducer itself via heat generation.

Perhaps everyone was aware of this but me? So, who’s turning their bow unit off/on when stowing the trolling motor while moving from spot to spot??

That’s a great theory and it sounds good but what does the owners manual say?

Never heard of that. Guess I’ve been doing it wrong hole hopping for 25 years with my flasher.

Immediate thought was also hole hopping. I was under the impression they had a rugged design barring a guy or gal doesn’t break a chunk off of it.

I have seen this referenced in other message forums, but never seen any reference to it in any manuals / documentation… which makes me wonder how legit it is.

I have on a couple occasions heard a faint ticking when walking past my boat trailer as it is parked in the driveway. After further investigation, I realized the sonar unit in the boat was still turned on and pinging away. It had been over 6 days, since the boat had last been used.

Maybe I was just lucky, but I never noticed any ill effects from this happening.

marineman wrote:

I have seen this referenced in other message forums, but never seen any reference to it in any manuals / documentation… which makes me wonder how legit it is.

Sounds like fear mongering to get attention.

I used to forget mine on all the time and never had a problem

BrianF wrote:

Apparently, the sonar will maximize power to the unit when the transducer is in air, trying to get a signal. This powerful air pinging can damage the internal circuitry of the head unit as well as the transducer itself via heat generation.

Sounds bogus to me. The transducer sends and receives a sound wave that is tuned for frequencies that work best in water. In air, it still sends the same sound wave at the same frequency, it just doesn’t receive it back because it doesn’t travel well through air. Thus, no reading shown on your screen in air. Your unit desn’t “maximize power to the unit when the transducer is in air, trying to get a signal”. It doesn’t “know” the difference, it has no intelligence, it’s just a machine.

Just found this on Humminbirds website. Couldn’t find anything on Lowrances site.

All tests should be conducted in a lake, pond, river or sea. Testing your transducer while out of the water can damage the transducer, the unit or both.

http://www.humminbird.com/support/faqs/DepthReadings

Doubt it will change anything for me. And if these manufacturers were honestly seeing damage while out of the water after all these years you’d think they would have found a way to automatically shut off just the transducer when it’s dry. Wouldn’t be all that hard.

Technically this is correct. Most transducers are designed to run operate at variable power levels and loads, yet if it is out of water, doing so can reduce their lifespan. Take the Vexilar vs Marcum, the older Vex’s had an output of 400 watts Pk to Pk while the Marcum has 2500 Watts Pk to Pk. There are all sorts of reasons for the higher power yet the lower power is definitely easier on your transducer, that is a fact. Sometimes locators do have have variable power levels as well a 50Khz pulse can be more strain than a 200Khz pulse dependent on how much energy is being applied to the crystal, so there are a lot of variables. Personally I wouldn’t spend too much time worrying about it however like I said, technically your best bet to maximize transducer life is to have it in the water while running. After 45 years of owning boats and portable units, I have never had to replace a transducer because it stopped working. (except when I ran into that rock!)

My Ray Marine Axiom with the 3D live transducer warns against running dry as it can if done too long lead to overheating the transducer. The heat generated needs water immersion to keep it running cool. This comes from the manufacturers owners literature.

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I’ve never noticed any negative effects from my ice units accidentally being turned on in the garage or travel, and running for days without me noticing. I’ve also heard its how the Russians are finding our fishing spots, and interfering with them.

To be honest, I never thought about this problem with an ice fishing sonar, rather more to protect the investment I have made in the Helix 12 G3 that is about to be installed on the bow of my boat.

Noticed that the peak-to-peak power output is 10X greater on the Helix 12 (4000 watts) than it is a Vexilar FL8 (400 watts). Could be more of an issue with these high powered open water units?

FWIW, I have had a number of transducers go bad inexplicable over the years, though not a head unit.