Escort see me without pinging

[Zosimus]

Originally Posted by BigWalleye

Yes, the pumps could be operated by hand. Everything on the boat except the propulsion could.But do you have a source that says that neutral buoyancy could be maintained indefinitely with hand-operated pumps? And that operating the pumps by hand was silent? Less noisy, sure, but a continuous noise source was all the escorts were listening for. And sound travels a long way in water.

Does anyone have a published source that says that a WW2 submarine could maintain constant depth indefinitely without operating electric motor-driven equipment? There are certainly first-person accounts (and technical documents) that indicate they couldn't.

No one is saying that the boat will hover indefinitely underwater. Yes, under normal operation the pumps are used to evacuate any accumulated water. However, under silent running, compressed air and hand pumps are used to maintain trim. Sure, one cannot vigorously operate a hand pump without making too much noise. Similarly even vigorous operation of a hand pump is not as efficient as just turning on a motor and letting it run. Compressed air will need to be used, and eventually it will run out.

However, even if the boat seems to be settling, maintaining depth is just as simple as angling the boat up slightly. Yes, this will result in a certain loss of forward motion, and yes, the boat will eventually fill up with so much water that the angle will end up being too extreme to maintain. Nevertheless the amount of water that a submarine takes on at periscope depth is negligible. The water just doesn't have that much pressure. On the other hand, at 100 meters under, the water will have 10 times the pressure and the amount of water entering will be substantially greater.

So no, I'm not saying that a boat can hover indefinitely at all stop 220 meters under the surface without running pumps. However, I don't see why someone would be all stop at that depth. If you really have run into a hunter-killer group, you need to make tracks. My boat can go 20 hours under before the CO2 hits 3. During that time I would hope to be at least 20 nautical miles away from the initial point of discovery and 30-40 would be better for my survival. So don't call all stop. Run silent, run deep, and run for your life.