Unknown Extremely loud sound?

[MB NZ]

I actually went diving today (more on that later). Something curious happened. Diving solo. Got down to about 16 metres and heard an almighty sound. It was like someone smacking a steel girder with a hammer right next to my ear. It was a clear sound, not muffled in the way that sound often is underwater. I've been round the block. Heard anchors dropping before. ****, I've had one nearly dropped on me! Heard boat crew bashing dive weights on the hull to get divers attention. I've heard ladders being dropped etc. Nothing compares to the clarity or volume of what I experienced today. I fully expected my next breath to be a mouth full of water because my first stage or tank valve had exploded, but nothing. Everything functioning normally. No ear trouble before or afterwards. Any thoughts?

 

[BoltSnap]

Dynamite fishing?? It happened to me many times. It was the worst thing that ever happened to me underwater. Initially, I thought my Tank had exploded, and I was dizzy for a few seconds. I realized that my Tank didn't explode since I was still alive. The fishing boat that dropped the dynamite was about 1km away the first time it happened. Other times, it was 1/2 - 1 km away. The bastard that dropped the explosives the first time died a year later when the dynamite he was using exploded in his boat.

It was the scariest experience I have ever had underwater. You feel it in your spine.

 

[Still Kicking]

Commercial fishermen used to drop "seal bombs" on us (u/w firecrackers) when we were diving in squid runs at night.

They were a loud thud - you''d feel them as much as hear them.

Nothing like the sound the OP described.

 

[lostsheep]

???

 

[OMyMyOHellYes]

Where were you?

Check for earthquake activity?

My earthquake dive included a series of loud higher pitched "pings" followed by really low, loud rumbling.

Or was it just a single accoustic impulse?

 

[Nemrod]

Maybe you got to close:

 

[lexvil]

I like the idea of an active sonar ping but it’s unlikely as most (US) subs don’t ping unless targeting or training but it’s possible. My experience with an earthquake seemed more like a boat passing overhead.

Curious situation.

 

[BoltSnap]

Illegal fishermen using dynamite to fish. They must be Australians coming in to take fish away from the Kiwis.

 

[Biotech Diver]

I like the idea of an active sonar ping but it’s unlikely as most (US) subs don’t ping unless targeting or training but it’s possible. My experience with an earthquake seemed more like a boat passing overhead.

Curious situation.

I actually went diving today (more on that later). Something curious happened. Diving solo. Got down to about 16 metres and heard an almighty sound. It was like someone smacking a steel girder with a hammer right next to my ear. It was a clear sound, not muffled in the way that sound often is underwater. I've been round the block. Heard anchors dropping before. ****, I've had one nearly dropped on me! Heard boat crew bashing dive weights on the hull to get divers attention. I've heard ladders being dropped etc. Nothing compares to the clarity or volume of what I experienced today. I fully expected my next breath to be a mouth full of water because my first stage or tank valve had exploded, but nothing. Everything functioning normally. No ear trouble before or afterwards. Any thoughts?

It doesn’t have to be a U.S. submarine. Every country with an underwater force or an anti submarine warfare capability uses active sonar.

 

[lexvil]

It doesn’t have to be a U.S. submarine. Every country with an underwater force or an anti submarine warfare capability uses active sonar.

I am only familiar with US boats but active sonar is a great way to meet a high speed fish no matter who’s country you call home port.