Radiated Sound Level?

[groomsie]

I think I've seen indirect references to being able to find how much sound you are radiating. Does this indeed exist? If so, is it part of a mod (and if so which mod) or part of the game (how do I find it?)?

Anyone ever heard or seen anything like this?

[SteamWake]

There used to be a 'noise meter' in SH3.

It was eliminated in SH4 by common concensous as being 'unrealistic'.

[groomsie]

Agreed, it does seem kinda unrealistic, just thought I'd seen it mentioned and wondered where it was...now I know.

[SteamWake]

The new noise meter is the behaviour of the DD's.

If they suddenly stop what there doing and start steaming right towards you at flank... your makin too much noise :p

[Nisgeis]

I find it annoying that even at silent running speed, you can still hear your own screws at 180, when you shouldn't be able to.

[BlueFlames]

I find it annoying that even at silent running speed, you can still hear your own screws at 180, when you shouldn't be able to.

Silent running isn't a magical switch that makes machinery stop making noise; it is an instruction to the crew to stop especially loud tasks and avoid making unnecessary noise. Driving a 1,200-ton steel tube through the water at four knots takes a fair bit of oomph, so yes, you're going to get a noticeable of engine and cavatation noise, even at one-third-ahead in silent running. The only way to truly silence the noise an electric motor makes in a hydrophone (be it yours or a destroyer's) is to turn it off.

Of course, when you start dialing it back to speeds of one to two knots, your own engine noise gets quiet enough that you'll be able to hear nearby and fast-moving ships over it, but the only way you're going to get the full effectiveness of your hydrophone in that rear arc is to stop the engine.

[SteamWake]

Alot of the reason you are deaf in the baffles is due to the turbulance in the water. Even if your only making turns for 1 knot your still stirring up the water, not to mention the beaings in the shaft. electric motor hum.

I dont know for certain but i would think if you couldent hear that noise there is something wrong with your sonar.

I have noticed... at least with RFB if you cut engines entirely you can listen at 180.

[LukeFF]

Originally Posted by SteamWake

I have noticed... at least with RFB if you cut engines entirely you can listen at 180.

That's just your own propeller noise. The American sonar sets will not pick up sounds from about bearing 150-210.

[Nisgeis]

Originally Posted by BlueFlames

Silent running isn't a magical switch that makes machinery stop making noise; it is an instruction to the crew to stop especially loud tasks and avoid making unnecessary noise.

Yes, thankyou. I am of course aware that there is nothing magical in a submarine. One of the sonar operator's most important jobs is to sweep over the sub on a flat or bass boost cycle filter and report any machinery that is making noise so that it can be secured.

Propeller noise occurs primarily because of cavitation on the tips of blades, or the blades themselves. There may also be some mechanical vibration of the blades. Cavitation is more likely at higher rotational speeds and lower pressure water. A slow turning prop would not cavitate. The sonar operator's manual states:

Own ship's screws are heard at 180 degrees, except during silent running.

Where is your source that says that this is not so? I'm all for learning new things.

[Nisgeis]

Originally Posted by SteamWake

Alot of the reason you are deaf in the baffles is due to the turbulance in the water. Even if your only making turns for 1 knot your still stirring up the water, not to mention the beaings in the shaft. electric motor hum.

The baffles are sound deadening material installed on sonar to attenuate the noise from the propellers, so the sensitive sonar receiver doesn't add energy to sound beams on a different bearing and give false readings. Even with engines stopped and the motionless, the performance astern of sonar with baffles is markedly reduced. If you have a look at a modern chin mounted sonar, it has sort of a teardrop shape, the circular section at the front has the sonar head in it and the section aft of that has a T shaped baffle. The first baffle stops the sound from the propellers and the second baffle perpendicular to it stops the front of that baffle reflecting sound from a different bearinginto the receiver.