Detection in game & reality

[Deamon]

...With the hydrophone I can pick up a potential target 20km+ away.
How come given how accurate the game is in many respects, it differs here? :hmm:



On one occasion in WWI a german u-boat in the atlantic detected a convoy with the hydrophones 100km away! What about that ? :P

But that were rare exceptions. In reality the possible detection range varies dramaticaly dependent on the sea state, sound speed profile, season, water depth, bottom type, plancton and algea populaition in the are of propagation. In winter for example you would achiev twice the range under the same conditions as in summer. But well if SHIII doesn't simulate all this aspects than it maybe has pretty fixed ranges and that is what can be complained about but 20+ kilometers in favourable conditions is pretty ok, especialy if it's a convoy. A convoy is always mutch further detectable than a single ship, this is also what needs to be taken in account when complaining the sonar model.

If you want to learn more about the ditails start maybe here:

http://www.fas.org/man/dod-101/navy/docs/es310/syllabus.htm

Scroll down to U/W ACOUSTICS & SONAR

Deamon

[Abraham]

Thanks for the interesting link, Demon

[Deamon]

In reality, there could possibly be an infinate number of variations for
cause & effect. But in gaming, it would be a nightmare to try & program
even 10% of them into a true simulation....


Many of the aspects are rather easy to programm. But some other aspects could be a nightmare indeed but approximations can be used instead. But still a hard part will remain that is to hard to code.

Deamon

[Col7777]

Wow a good thread,

I have listened on the hydrophone and heard nothing and not been warned by the operator of any ships, but my watch crew has spotted them.
Then I've spotted ships before my watch crew on other occasions too.
I've seed destroyers almost stop in the water trying to pick me up then suddenly serge forward again perhaps looking for another spot or they have picked me up.
Then I've also been in the middle of a convoy and NOT been detected, and again been in the same position and BEEN detected, so I'm not sure if certain water/weather conditions apply in the sim or not as to being detected and detecting other ships.
Having said all that I think I would like my hydrophones to be a little better than they are though.

[U-1966]

Ah yes! I love being the one to solve a controversy. How about from the mouth of the master himself Otto Kretschmer.

From the book "The Golden Horseshoe, The Wartime Career of Otto Kretschmer, U-Boat Ace."

From page 83. Otto lists 12 standard operating procedures for
U-99. Number 12 reads and I quote:

"U-99 will dive for two hours just before dawn each day at sea. This will serve twofold purposes: first it will avoid the risk of running into ships and planes we have not seen during the night and which might see us first; and secondly IT GIVES US A CHANCE TO USE THE HYDROPHONES TO SWEEP FOR UNSIGHTED SHIPS. In addition, it gives the crew an opportunity to relax, clean up and have breakfast in peace"


So diving to detect ships is not as one poster said "arcade like". It is Historically accurate. The Mods I use do not allow lone ship contacts to appear on the map unless seen by the crew. So I use Otto's method above to sweep for targets two hours every morning. I have managed to pick up 2 ships in three patrols with just that method. Pretty realistic I think.

[Deamon]

Thanks for the interesting link, Demon

Never minde mate.

Here's one more very interesting one on shallow water acoustics:

http://www.npmoc.navy.mil/KBay/shallowacoustics.htm

In shallow water the detection ranges must be mutch shorter than in deep waters, like in atlantic for example.

Here's one more:

http://www.fas.org/man/dod-101/sys/ship/deep.htm

You might finde this interesting as well:

http://www.fas.org/man/dod-101/sys/ship/acoustics.htm#levels
http://www.pmel.noaa.gov/vents/acoustics/tutorial/tutorial.html
http://www.fas.org/man/dod-101/navy/docs/fun/part08.htm
http://www.fas.org/man/dod-101/navy/docs/fun/part09.htm
http://www.fas.org/man/dod-101/navy/docs/fun/tass.htm
http://www.fas.org/man/dod-101/navy/docs/fun/season.htm

Deamon

[Tullaian]

My conclusions are that;

a) regardless of skills and weather conditions you won't get a visual contact further out than 8km. The ship just won't be drawn in game. Big disadvantage to visually acquiring targets in good weather as historically they could see things even 20-30km away in good conditions.

b) conversely in poor weather and or bad light the computer watchers will visually ID targets at ranges well beyond your ability to visually see anything. I've had visual contacts reported by the WO at night in 15m seas at 3km , when I won't be able to see the ship till it is under 300m. Similarly the green/yellow/red triangles will light up a target via the scopes often well outside actual visual acquisition range.

c) hydrophone range seems to be 20km regardless of weather conditions and model. Thermocline , water density , depth etc. all don't seem to impact that to any great deal. I can't see a difference between target acquisition at 20m , 40m or 80m. I use 40m since someone said that is historically what the Uboats used, but I can hear the targets just as well at the other depths.

d) hydrophone operators seem inconsistent. I've had them call out contacts I can barely hear manually and then lose contact at a range where my wife playing on the next PC can hear the contact. They can also track targets while surfaced for a period of time but they will eventually lose a target it you surface for extended periods (15-20m ? ). Once they lose the target if surfaced you won't be able to hear it again till you dive.

[JohnnyPotPie]

I call it scoot and sink, wash rinse and repeat... Using the hydrophones to pick up on enemy ships is by far more effective than just cruising about hope'n to get lucky. For some reason even with really good weather and visibilty you cant seem to see smoke on the horizon. In WW2 was this tactic of submerging and listening an accurate simulation of UBOAT combat during ww2. Personaly I would think you could see farther than you could hear, due to technology of the time. :hmm:

[Abraham]

This is really the revival of a long lost thread...

@ Demon: thanks for the extra links!

@ Tullaian: I fully agree with your conclusions.
By the way, are your wife and you that close?...
d) hydrophone operators seem inconsistent. I've had them call out contacts I can barely hear manually and then lose contact at a range where my wife playing on the next PC can hear the contact...
:D