how to be undetectable?

[CapitanPiluso]

Here you can find some more (real world) info

http://www.maritime.org/fleetsub/sonar/index.htm

[allanon87]

first of all thanks guys for answer, very useful. thanks for the document it's great!!Back to thread.

you're right i'm in shallow water so there isn't a thermal layer, so i will stay deep, but now i know that i can go faster than 1-2 knots. In fact for fear to be detected that was my operation speed.
thanks for the document it's great!!.
About passive sonar: when i stay near the floor of the sea enemies can hear me with more difficult...that's mean even me can hear him more difficult?

[Pisces]

Originally Posted by allanon87

...

About passive sonar: when i stay near the floor of the sea enemies can hear me with more difficult...that's mean even me can hear him more difficult?

Won't work. You make the same amount of noise near the bottom as above. Until you make a nose dive, then you are louder.

Active sonar directed at you might theoretically give you an edge because the echo of the bottom and your echo almost coincide. But don't count on it. Your sub is still a very good reflector compared to the seabottom. And in-game I don't think this is modeled at all.

[allanon87]

i assumed that the different speed of the sound between sea floor and surface helped me to be more undetectable....so i was wrong.
but i'm quite sure that near surface (20m depth for expample) an enemy radar can find me, that's right?

[Pisces]

Originally Posted by allanon87

i assumed that the different speed of the sound between sea floor and surface helped me to be more undetectable....so i was wrong.

Oh ok, you mean curved soundwaves because of soundspeed changes with depth. In reality the sound is curved towards depths with lower soundspeeds. So it is either bend back to the surface, or into the depths if there is a maximum. And both bottom and surface might cause it to reflect. If there is a minimum speed somewhere, then the sound is bobbing up and down around that depth. This is called the deep sound channel. How the sound curves from or towards you is complicated, especially how much of it arrives at the listener. Dr.Sid made a simulation program to illustrate this by ray-tracing. It's called SoPro iirc. There should be a thread about it somewhere over here.

The game simplifies this sound physics allot. On the other side of a layer you are pretty much undetectable. Unless you get within a certain distance from a surface contact, then it is a direct path detection. This distance is dependent on your depth. DrSid did found this out in a series of tests on detection ranges some years ago. Again, do a search.

but i'm quite sure that near surface (20m depth for expample) an enemy radar can find me, that's right?

Radar doesn't penetrate water. But sometimes you do if you are too close to the surface, and the waves are bad.