[Sarah Barracuda]

My guess is they are fish food, they keep on talking about “Pinging” every 30 minutes..reminds me of MH370 they heard “Pinging” too which amounted to nothing the sub probably is stuck in the wreckage of the Titanic

[cableguymn]

not even enough of them left for the fish.

[Bonemaker]

“..they keep on talking about “Pinging” every 30 minutes...”

Whales.

[Pajamajan]

"the sub probably is stuck in the wreckage of the Titanic"

Yeah, stuck in the wreckage of the Titanic, which the designers ironically, also didn't think needed too much safety equipment.

[Pete from Shawnee Mission]

Currents at the bottom could be bouncing the wrecked submersible against the hull of the Titanic, making a banging noise.

In the 1959 movie "On the Beach" all human life in the northern hemisphere has been killed due to a nuclear war a U.S. Submarine was sent to see if the radiation is dispersing and to find the source of a radioed telegram signal.

(From IMBD) "The submarine next stops at a refinery near San Diego, which has been pinpointed as the source of the mysterious Morse signals. A crew member discovers the power source is still running on automatic control. Nearby, a telegraph key has become entangled in a window shade's pull cord and a half-full Coca-Cola bottle, and is being randomly pulled by an ocean breeze, causing the radio signals. "

Something like that.