First time being depth charged - Evaision Advice?

desirableroasted · 02-26-11, 09:09 PM

Quote:

Originally Posted by USNSRCaseySmith

The hydrophone overshooting me?? Ive never heard of this, could you elaborate more??

I knew you would ask, and I can't find the diagram. I hope some helpful soul can round it up.

EDIT: I have removed several lines of inaccurate information here. My apologies!

See Sailor and Tom's notes below.

Bakkels · 02-26-11, 09:42 PM

If you're running GWX3.0, a detailed explanation can be found in the manual, in the gameplay appendix

Sailor Steve · 02-27-11, 10:55 AM

Quote:

Originally Posted by desirableroasted

I knew you would ask, and I can't find the diagram. I hope some helpful soul can round it up.

The escort's hydrophone's has a cone around the escort in which it can sense you. IIRC, it can (but won't always) sense any noise between the surface and a 45-60 degree angle down.

Thus, the deeper you are, the closer you can be to the escort without being detected, as his hydrophone cone may be overshooting you.

It is imperfect, and as far as I know, the diagram was illustrative, not definitive, but it seems to work. As you have probably noted yourself, 150 meters may be 3 times as deep as 50 meters, but it's 10 times safer.

Sorry I missed this first time around.

The stock game doesn't represent this, but they made it adjustable, so GWX does.

Basically by the time he's actually dropping depth charges, he can't actually hear you anymore.

Tom · 02-27-11, 11:50 AM

Quote:

Originally Posted by desirableroasted

I knew you would ask, and I can't find the diagram. I hope some helpful soul can round it up.

The escort's hydrophone's has a cone around the escort in which it can sense you. IIRC, it can (but won't always) sense any noise between the surface and a 45-60 degree angle down.

Thus, the deeper you are, the closer you can be to the escort without being detected, as his hydrophone cone may be overshooting you.

It is imperfect, and as far as I know, the diagram was illustrative, not definitive, but it seems to work. As you have probably noted yourself, 150 meters may be 3 times as deep as 50 meters, but it's 10 times safer.

I think that is how active sonar works. The ship sends a sound pulse in a direction, and listens for echoes. The devices for sending the sound pulse couldn't be directed downwards, so once you're close enough to the ship he can't ping you.

So, in order to avoid active sonar, being pinged, you must be either far enough for the sonar to not reach you effectively (out of range), or deep enough and close enough, that the sonar beam overshoots you. If neither of these is possible, presenting as small a profile as possible helps lower your echo very much, possibly allowing you to not be detected. The further away you are, the lower your echo. Your speed or sound level doesn't effect the ability of active sonar to find you.

Hydrophones, on the other hand, are passive microphones, and they can detect you from any direction, except from the baffles, where the sound of the ships own engines and screws will mask any other sounds.

The most important thing when avoiding passive hydrophones, is being as quiet as possible. Distance helps too, both downwards and horizontally. Furthermore, a thermal layer may greatly reduce the ability of hydrophones to hear you. Keeping a low profile, which was the most important method of avoiding sonar, does nothing to help avoid being heard by hydrophones (except that keeping your stern pointed towards the listening enemy usually moves you away from it, thus lowering your sound level.)

timmy41 · 02-27-11, 12:21 PM

Whether or not the ASDIC is audible to humans depends on its frequency. Generally, or so ive read, earlier ones had a frequency in the higher spectrum of human hearing, and later in the war there were even higher frequency ones that people couldnt hear, but feel because the boat would vibrate.

LordCucumber · 02-27-11, 02:27 PM

Quote:

Originally Posted by Tom

(except that keeping your stern pointed towards the listening enemy usually moves you away from it, thus lowering your sound level.)

Ok... so what if you would back up silently with your nose to the enemy instead of heading away with your stern to the enemy.. Would your own boat's profile mask the sound (blocking it if you are facing the enemy on 0 degrees)?

Tom · 02-27-11, 02:47 PM

Quote:

Originally Posted by LordCucumber

Ok... so what if you would back up silently with your nose to the enemy instead of heading away with your stern to the enemy.. Would your own boat's profile mask the sound (blocking it if you are facing the enemy on 0 degrees)?

Your boats profile doesn't mask sound as far as I know, at least not in the game. Perhaps realistically speaking, if you moved in reverse, your hull would be in between the destroyer trying to listen for you and your screws, which generate noise, dampening the noise a bit. Moving in reverse is slower though - the same RPMs would move you a bit faster ahead because of the submarine's shape. So moving ahead is probably a better idea anyway.

In game, your sound level depends only on engine RPMs and silent running status (repairs, loading torpedoes etc. cause noise), as far as I know. Your depth and distance from the ship listening for you determine if this sound will be heard or not. Your aspect or direction of movement do not matter.

But if the listening enemy switches to sonar instead, aspect immediately becomes the most important factor and sound level isn't important anymore. Unless, of course, some other ship is still listening, or the ship using asdic switches back to passive listening.

Thus, moving as silently as possible and maintaining as narrow a profile as possible is always the best plan.

Sailor Steve · 02-28-11, 01:45 AM

Quote:

Originally Posted by LordCucumber

Ok... so what if you would back up silently with your nose to the enemy instead of heading away with your stern to the enemy.. Would your own boat's profile mask the sound (blocking it if you are facing the enemy on 0 degrees)?

Real life? WW2 submarines couldn't stop underwater, and trying to back up while submerged would make the boat extremely difficult to control. You'd probably make it worse if you tried that. Even surface ships are difficult to control in reverse.

desirableroasted · 02-27-11, 03:08 PM

Quote:

Originally Posted by Tom

I think that is how active sonar works.

I stand absolutely corrected...

sharkbit · 02-27-11, 03:11 PM

Pray they don't have Hedgehogs!

FlankSpeed · 02-27-11, 03:13 PM

Are hedgehog and squid launchers modeled in the game for the later war?

sharkbit · 02-28-11, 06:09 PM

Quote:

Originally Posted by FlankSpeed

Are hedgehog and squid launchers modeled in the game for the later war?

Hedgehogs are modeled in the game.

Squids are not.

maillemaker · 03-01-11, 01:41 PM

Depth is your friend. Late in the war, your best chances of survival are to go as deep in the yellow zone as you can. An undamaged sub can go right to the end of the yellow zone no problem. Once my boat sustains any damage, I no longer go after escorted targets as I can't go deep enough to get away.

02-26-11, 09:42 PM	#2
Bakkels Seasoned Skipper Join Date: Jan 2011 Location: Groningen, The Netherlands Posts: 709 Downloads: 101 Uploads: 6	If you're running GWX3.0, a detailed explanation can be found in the manual, in the gameplay appendix __________________ My sh3 skins : http://www.gamefront.com/files/user/Bakkels Or go to the sh3 downloads section > skins

02-27-11, 03:11 PM	#10
sharkbit The Old Man Join Date: Apr 2008 Location: Denver, CO Posts: 1,529 Downloads: 334 Uploads: 0	Evasion Advise? Pray they don't have Hedgehogs! __________________ “Prejudice is blind. There will always be someone who says you aren’t welcome at the table. Stop apologizing for who you are and using all your energy trying to change their minds. Yes, you will lose friends, maybe even family. But you will gain your self-respect. You will know your worth. Once you have that, nothing can stop you.”

02-27-11, 12:21 PM	#5
timmy41 Weps Join Date: Mar 2010 Posts: 367 Downloads: 9 Uploads: 0	Whether or not the ASDIC is audible to humans depends on its frequency. Generally, or so ive read, earlier ones had a frequency in the higher spectrum of human hearing, and later in the war there were even higher frequency ones that people couldnt hear, but feel because the boat would vibrate.

02-27-11, 03:13 PM	#11
FlankSpeed Seaman Join Date: Feb 2011 Posts: 32 Downloads: 12 Uploads: 0	Are hedgehog and squid launchers modeled in the game for the later war?

03-01-11, 01:41 PM	#13
maillemaker Sea Lord Join Date: Apr 2007 Posts: 1,639 Downloads: 75 Uploads: 0	Depth is your friend. Late in the war, your best chances of survival are to go as deep in the yellow zone as you can. An undamaged sub can go right to the end of the yellow zone no problem. Once my boat sustains any damage, I no longer go after escorted targets as I can't go deep enough to get away.