How SONAR Works

Summary

In this video, the dangers of submarine sonar to divers are explored. Sonar, used by submarines for navigation, emits sound waves that can be extremely loud. Active sonar pings, reaching up to 235 decibels, can cause severe injuries or even death to humans. Unlike bats' harmless ultrasonic sonar, submarine sonar operates at much lower frequencies, making it far more dangerous. However, submarines typically avoid using active sonar near coastlines due to regulations protecting marine life. Despite the risks, the chance of encountering harmful sonar while diving is rare, thanks to these precautions.

Takeaways

• 😀 SONAR stands for Sound Navigation and Ranging, a technology used by submarines to detect objects underwater.
• 😀 There are two types of sonar: Active (which emits sound pulses) and Passive (which listens for ambient sounds).
• 😀 Active sonar works by sending out sound pulses and measuring the time it takes for them to return, allowing the submarine to calculate object distances.
• 😀 The decibel level of active sonar can reach up to 235 decibels, which is extremely loud and potentially harmful.
• 😀 Sounds above 194 decibels are classified as shockwaves, and in water, they can be far more intense and dangerous.
• 😀 A 235-decibel sonar ping could potentially burst your lungs and cause brain hemorrhaging, leading to death or severe injury.
• 😀 Bats also use sonar, but their frequencies are ultrasonic (20-200 kHz), much higher than human hearing, and much less harmful.
• 😀 Submarines typically avoid using active sonar near coastlines due to regulations that aim to protect marine life.
• 😀 If submarines detect marine life, they must reduce or turn off their active sonar to avoid harm to the environment.
• 😀 Although active sonar can be dangerous, it is unlikely a submarine would use it casually near divers, as it would compromise its stealth.
• 😀 In the ocean, threats to divers from submarines are minimal, with other dangers, such as natural predators, posing a greater risk.

Q & A

What is SONAR and what does it stand for?

SONAR stands for SOund Navigation And Ranging. It is a technology used for navigating and ranging objects underwater using sound waves.

Why is SONAR preferred over RADAR or light for underwater navigation?

Sound waves travel much better through water than RADAR or light, which is why SONAR is used for underwater navigation and detection.

What is the main difference between Active and Passive SONAR?

Passive SONAR listens to sounds in the water, such as marine life or ships using active sonar. Active SONAR, on the other hand, sends out sound pulses and listens for the echoes to determine the distance of objects.

How does Active SONAR work?

Active SONAR works by emitting sound pulses and measuring how long it takes for the sound to return after bouncing off an object. This information helps calculate the distance to the object.

What is the potential harm of an Active SONAR ping for divers?

A loud SONAR ping can be as intense as 235 decibels, which can cause severe damage, such as bursting lungs and brain hemorrhaging, potentially leading to death. At minimum, it would leave a person in critical condition.

What is the loudest sound a human can hear before eardrums rupture?

The loudest sound a human can hear before their eardrums are damaged is around 160 decibels.

How does the loudness of sound differ in water compared to air?

In water, sound can be much louder than in air. While sounds above 194 decibels in air are considered shockwaves, underwater, sounds can exceed these levels and cause significant harm.

Why don't bats' sonar sounds cause harm to them or other animals?

Bats use ultrasonic sonar, which is at a frequency range of 20 to 200 kilohertz. Humans can't hear these high frequencies, and the sounds are much lower in volume (about 120 decibels), which does not cause harm.

Why do submarines typically avoid using Active SONAR?

Submarines avoid using Active SONAR because it compromises their stealth. Active SONAR emits sound that can be detected by others, revealing the submarine's position, which goes against their main tactical advantage.

Are there any legal restrictions on the use of SONAR near coastlines?

Yes, ships are not allowed to use Active SONAR within 12 nautical miles of a coastline to protect marine life. If any marine life is detected, the submarine or ship must turn off or reduce the power of their Active SONAR.