Enemy sonar at medium speeds?

[Sailor Steve]

5000 meters is 5 kilometers, which is only 3.1 miles. I was unhappy when an escort in NYGM spotted me at 7000 meters, but 5000 doesn't seem unreasonable.

Now that I think of it, 7000 meters is only 4.2 miles. Someone recently posted that the horizon from the conning tower of a sub is around 8 miles, and ships can be seen a lot further away than that.

My fifth patrol, in mid-January 1941, I was at 14 meters, doing 1 knot, as a Black Swan was slowly moving towards me. It was the lead escort of a convoy, I'd been in position for 1 hour at 1 knot (so it's not as if they had advanced warning I was even in the vicinity).

I didn't position myself quite where I'd wanted: I was pointing directly towards the convoy track, which meant it (and the frigate) was heading straight towards me. Which is what I wanted, except I'd wanted to be positioned so the frigate would pass to one side of me around 1.000 - 1.500 meters off to the side. Instead it was closing to pass within only a couple hundred meters.

While still at 15 meters, scope never being raised once the frigate had closed to 2.500 meters, and still at 1 knot, running silent, I was tracking it manually on the hydrophones. When it was approximately 400 meters away I suddenly heard its screws crank way the heck up. Then, 5 seconds later, it started actively pinging.

I'd dearly love to know what reason it had to detect me

[Trygvasson]

Originally Posted by Albrecht Von Hesse

.... still at 1 knot, running silent, I was tracking it manually on the hydrophones. When it was approximately 400 meters away I suddenly heard its screws crank way the heck up. Then, 5 seconds later, it started actively pinging.

I'd dearly love to know what reason it had to detect me

Sounds like an Elite hydrophoneman heard your 1 knots. How do you manage to run at 1 knot anyway? were you maneuvering at Dead Slow? Any maneuvering or speed increases your audio signature, you are advised by BDU Lehmann that the only real silent running is a full stop.

[robj250]

Originally Posted by Sailor Steve

5000 meters is 5 kilometers, which is only 3.1 miles. I was unhappy when an escort in NYGM spotted me at 7000 meters, but 5000 doesn't seem unreasonable.

Now that I think of it, 7000 meters is only 4.2 miles. Someone recently posted that the horizon from the conning tower of a sub is around 8 miles, and ships can be seen a lot further away than that.

Thanks Steve
I just happened to remember that in the original Silent Hunter, I has developed a charting board based on the radar of the US subs and the maximum distance for radar to pick up a convoy or ship was 17 nautical miles (of course - depending on the height of the radar itself)