Escort see me without pinging

[maillemaker]

I have always assumed that the logic was that no submarine is completely silent, and so if they get close enough a diligent passive operator will hear the sub.

While you are in the sub submerged at any depth you are always hearing creakings and groanings from the boat.

Steve

[Paulebaer1979]

Originally Posted by maillemaker

While you are in the sub submerged at any depth you are always hearing creakings and groanings from the boat.

Today that´s wrong. In a well trimmed sub with "all stop" you only can hear the crew. The hull doesn´t make noise because the pressure doesn´t change - if the sub don´t change its depth.
I guess it was so in the past, too. So we have a silly bug in our nice game.

[BigWalleye]

Originally Posted by Paulebaer1979

Today that´s wrong. In a well trimmed sub with "all stop" you only can hear the crew. The hull doesn´t make noise because the pressure doesn´t change - if the sub don´t change its depth.
I guess it was so in the past, too. So we have a silly bug in our nice game.

As I have read, it was a bit different in WW2 They didn't have the vibration isolation and sound deadening technologies in use today. To hold depth at "all stop" you have to operate the pumps. Turn on the pumps and the escorts hear the noise. Turn off the pumps and the sub settles, as numerous small leaks let water in. And, as the sub settles, the hull compresses, increasing displacement, so you settle even more....

All this is modeled in Stiebler's "Slient Running" patch. Makes an interesting dilemma for the Kaleun!

BTW, escorts have passive hydrophones too, and they are of much longer range that active. They don't have to ping to detect you. Pinging, even today, is primarily for a targeting solution.

[BigWalleye]

Originally Posted by BL!TZKR!EG

Which is one of the things I cannot agree with.

I spoke to a former U-Boot-Kaptain about this. His words were: "That exactly is LI's job when submerged: the correct trimming. And then the boat lies stable in the water. Nothing changing. I would have shot my LI if we were to sink only because not using the pumps"

So where did this funny idea originate from?

From a number of first-person accounts, including Werner's, AFAIK. Why would he bottom the boat if it could hover? You can hold trim for a while, but the boat does continuously take on water. As long as water is coming in, water must go out or the boat will settle. How can trim be maintained without running the pumps? How can neutral buyancy be maintained without running the pumps? Technical manuals and first-person accounts all indicate that the submarine could not "hummingbird" for an indefinite period.. It could maintain trim and bouyancy for a while, but not indefinitely. Sooner or later, either pumps or motors would have to be operated to maintain depth.