Sonar and phones simultaneously

[KrazyDimondRX]

Hi everyone,

I read somewhere (cant recall source ) that when a persuing ship is pinging you, they cant use their phones to track you. i.e it's one device or the other.

Now i understand the theory, but can anyone tell me wether this rule applies on sh3??

Secondly, if the rule does apply in sh3, does that mean they cant hear me when they dont receive the returning ping (nothing). Or only when their ping is returned ("The enemy is pinging us sir" ) ???:hmm2:

Thanks in advance,
KDRX

[Mittelwaechter]

The passive hydrophone hears a braod band spectrum of sound waves. Any kind of noise was detectable, of course dependent on own speed as of distance and level of the noise source.
The active hydrophone (ASDIC/Sonar) emitted a 'ping' - a sound bubble with it's perimeter expanding 360°. Any object hit by this perimeter reflected the ping and partially back to the emitter.
The active hydrophone had special (passive) receivers for the own ping frequency. Different models were developed. Common was a mixture of a pretty 'broad' receiving device and a small extra sensitive search device. Both devices were turnable and searched for the ping echoes. If a U-Boot was hit by a ping perimeter it reflected some of the sound back to the emitter/receiving device. If the broad search receiver was turned into the direction of the U-Boot it could receive this echo under given circumstances. This echo was transformed into an electric signal and visualised for the ASDIC/Sonar operator.
The broadband passive only hydrophone would have heared a very loud echo of the ping, therefore it wasn't used while active ping operations.
The extra sensitive search device was able to receive the echo only in a very small cone - therefore ideal to determine the correct course to the target. Even the depth of the object could be detemined with this 'search beam' (it wasn't a beam at all), because the listening cone was adjustable (up to a certain degree) in search height (or better search depth) too.
The distance to the object was measured by the time it took a ping to travel back to the receiver.

The U-Boot crew never knew if they were detected after being hit by a ping until the actions of the search dog were interpretable.
This is indicated by "... is pinging US!" They go for US right now. In the German version they say "We are detected!"

As I understand it, in SH3 the passive hydrophone stays operational all the time and it works perfectly even after a depth charge run destroyed the usable audio conditions completely for several minutes.
There is only a fixed deaf spot in the wake of the vessels due to their own propellor noise and the hydrophone doesn't work as long as the attacker is at high speed (to avoid it's own depth charges).
The ASDIC can't cover the area under the ships hull and a short deep zone forward as the complete 90° to 270° sector aft. Under good conditions the ASDIC will detect you within ~1800 meters if you show your broad side or your upper deck and the dive planes to reflect the ping.

[KrazyDimondRX]

Thanks for the reply:up:

Most would agree standard operating procedures are to "ahead flank" and full rudder when splashes are heard.

I always thought the charges were masking our subs, but your telling me its their own prop wash masking our escape??

"As I understand it, in SH3 the passive hydrophone stays operational all the time and it works perfectly even after a depth charge run destroyed the usable audio conditions completely for several minutes."

If i'm understanding correctly you're saying after a depth charge run (passive)phones are still working/running/operating but fruitlessly? kind of like a refigerator with its door left open?

Thanks again,
KDRX

[Mittelwaechter]

The passive hydrophone is working and will pick you up if you are noisy after you get out of the DD's deaf zone, either by the turning DD or you manouvering into the detectable area. As soon as you get into his ~210° to ~150° area you are detectable if you are noisy enough, no matter what happened before.

If a DD passes/overtakes without depth charging you - i.e. on his regular patrol course, you may power up as long as you stay in his "six", even if he is slow.

[KrazyDimondRX]

gotcha:up: ok cool.

Thanks for walking me through that.
It's 1943 things are pretty tough, air cover is remorseless, thought i'd found me an underwater loophole.

Thanks again Mittelwaechter :salute: (http://www.subsim.com/radioroom/member.php?u=230860)

KDRX