Accidentally hearing an active submarine sonar while underwater has devastating effect on human body

Accidentally hearing an active submarine sonar while you’re underwater can have a dire effect on your body.

Sonar technology is pretty much the best thing since sliced bread when it comes to exploring deep seas and mapping large bodies of water.

Typically the unsung hero of huge cases, it was used when search crews were looking for the billionaire-filled Titan sub last year.

Oh, and it was also used by the researchers who found a 30-ft long mass lurking in the depths of Loch Ness – even if wasn’t Nessie herself.

But with it being such a handy bit of tech, you’d probably assume sonar (short for Sound Navigation and Ranging) is completely safe.

However, that’s not totally the case because active sonar transducers emit acoustic signals or pulses of sound into the water with the hope that it runs into any objects that may be of interest - yes, runs into.

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So, if this is the case, then the sound sent out will bounce back off the item, returning an 'echo' to the system which can then calculate the strength of the signal, while giving the operators an idea of what it may be.

Whereas passive sonar simply means listening for the sound made by vessels, which is probably why we all have such a false sense of security surrounding the technology.

We use sound to detect things below the surface as light doesn't travel very well underwater, while ships also use sonar to help them navigate the waves and to effectively 'see' what is in their path.

Most boats are equipped with active sonar technology these days, but obviously its power pales in comparison to that of huge navy ships.

A gang of Australian divers found this out the hard way back in November last year, as they were right in the firing line of the sound pulses when a Chinese vessel blasted its sonar.

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The country's defence minister, Richard Marles, said the HMAS Toowoomba paused while it was in international waters after its propellers ended up tied up in fishing nets.

The divers were sent out to remedy the problem, but China's PLA-N destroyer (DDG-139) ship was also operating close-by and, despite being warned an operation was underway, it 'approached at a closer range'.

Marles said: "Soon after, it was detected operating its hull-mounted sonar in a manner that posed a risk to the safety of the Australian divers who were forced to exit the water.

"The divers sustained minor injuries, likely due to being subjected to the sonar pulses from the Chinese destroyer."

When high levels of active sonar are used, it can cause dizziness, disorientation, temporary memory issues, concentration problems and temporary hearing loss.

In serious cases, it can even cause organ damage.

Marine bioacoustics scientist told the West Australian that active sonar pulses can rupture the lungs, while ones which exceed 210dB can cause fatal brain haemorrhaging.

Divers would likely hear a mid-to-high pitch sound while underwater when the active sonar is emitted, cluing them into the fact that they may be in serious danger.

So if your ears ever start ringing while you've gone for a dip in the ocean, maybe you should resurface - fast.