Resting on the bottom for a few hours..

JamesT73J · 02-08-10, 05:04 PM

Playing SH3 + GWX Gold and have dropped into the Med for a quick look at Gibraltar, late 1940. Got within a couple of km's of the port in absolutely foul weather at night; lots of traffic and escorts. My plan was to lie on the bottom overnight in about 70m of water, and have a peek through the periscope in the morning, then surface in the evening and sink some stuff.

Bottoming out was easy enough, but after after about 6 hours an escort passed nearby and pinged me, and of course utterly trashed my sub once the charges came.

I'm curious how I was detected. I realised too late that although I was at full stop, I hadn't chosen silent running. Is there enough noise from a submerged, still sub to allow passive sensor detection in SH3?

Cheers

James

Submarine · 02-08-10, 05:40 PM

Water is one of the best transmitters of sound, and there are stories of ships picking up u-boat crew members talking and that is all they need. So without silent running, you are always screwed

ryanglavin · 02-08-10, 06:16 PM

If you don't have silent running on (theoretically, you can't really prove this), the crew could still make all the noise and eat and walk around as much as they want.

Lord Biceps · 02-08-10, 10:43 PM

The game doesn't appear to recognize landforms in any other sense than that they can't be navigated through. In other words, the ship pinging you only finds your sub, not the land you're resting on, as if your sub had been floating freely in the water.

You can also spot ships (and be spotted) through land. This caused quite a bit of trouble for me at Scapa Flow recently, as I was being bombarded by warships from several directions while being completely sheltered (or so I thought) by surrounding islands and coastlines, and not being able to even visually locate where the shots were coming from.

This is a major annoyance for me, I hope they'll fix it in SH5 (or did they do that in SH4? I haven't played it yet).

GoldenRivet · 02-08-10, 11:10 PM

Quote:

Originally Posted by Lord Biceps

(or did they do that in SH4? I haven't played it yet).

this was not fixed in SH4

I wouldnt hold my breath awaiting the correction to arrive in SH5 either

krashkart · 02-08-10, 11:40 PM

Hrm, good stuff to know. Accidentally engaged a destroyer (*cough* The game cheated, I swear!) and had to dive in a hurry. Very glad I remembered the silent running mode, I think it helped spare the sub and crew. Took a good thumping from the ashcans but was able to slip away. Just glad their gunners had bad aim.

Frank0001 · 02-09-10, 12:26 PM

Quote:

Originally Posted by JamesT73J

I'm curious how I was detected. I realised too late that although I was at full stop, I hadn't chosen silent running. Is there enough noise from a submerged, still sub to allow passive sensor detection in SH3?

Odd really, that must mean the escorts are always listening/pinging, even when without suspicion?

JamesT73J · 02-09-10, 01:37 PM

I don't think the idea of a coastal ASW vessel being on constant sonar watch that strange; it's probably a standing order; I know they certainly were when on escort duty. It must be hard work with such a shallow environment with lots of traffic. Anyone try SH1? Coastal DD's used to ping constantly, and they usually detected you.

I'm going to replay later trying the silent running method. If I'm detected passively I can only assume that there is some noise emission even on silent running.

I come from SC / DW with the knowledge that all platforms emit noise all the time, to some extent, so it's merely a matter of the emitter being close enough to the listener before detection occurs; it was therefore highly unlikely that one could close on a vessel with listening gear unless acoustic conditions were very very bad.

Frank0001 · 02-09-10, 02:31 PM

I've had a few times where I'd wait on course of a fat convoy, silent running and engines off. The escorts would still pick me up if they're close enough.
Sometimes they just sail happily by.

GREY WOLF 3 · 02-09-10, 02:32 PM

Astic is A system using transmitted and reflected underwater sound waves to detect and locate submerged objects or measure the distance to the floor of a body of water. So with no sound at all it picks up THAT BIG MASS of metal in your case a sub.

Jimbuna · 02-09-10, 04:05 PM

You need the cloaking device mod otherwise there is no way of hiding your presence.

Stoooopid game engine

Dave Kay · 02-10-10, 12:10 AM

Quote:

Originally Posted by GoldenRivet

this was not fixed in SH4

I wouldnt hold my breath awaiting the correction to arrive in SH5 either

Good thing you pointed that out GR, because I was just about to turn blue-in-the-face until I read further down and saw your post....

:haha :

Torvald Von Mansee · 02-10-10, 12:29 AM

Quote:

Originally Posted by Frank0001

Odd really, that must mean the escorts are always listening/pinging, even when without suspicion?

Sigh...the RN and USN seem to always be on an artificially high level of alert. I don't think it's terribly realistic.

Of course, water as clear as a bell while sneaking into Loch Ewe is probably also not very realistic, either.

Leandros · 02-10-10, 02:57 AM

Quote:

Originally Posted by GREY WOLF 3

Astic is A system using transmitted and reflected underwater sound waves to detect and locate submerged objects or measure the distance to the floor of a body of water. So with no sound at all it picks up THAT BIG MASS of metal in your case a sub.

But then you ought to hear the pinging. My experience is that, for a example a lead escort, only starts pinging after it has got suspicious about you.

JamesT73J · 02-10-10, 03:57 AM

Quote:

Originally Posted by Leandros

But then you ought to hear the pinging. My experience is that, for a example a lead escort, only starts pinging after it has got suspicious about you.

This is my experience. ASW units seem to listen passively, then locate using active sonar. I notice that silent running disables torpedo loading, pumps, the snort mast (if you have one); I suspect SH3 sums these things (along with your motor and screw noise) into an emissions total. There appears to be no particular penalty for having the pumps switched off; in AOD you couldn't do this for long periods as you'd start to sink as the bilge filled up.

I tried the scenario again, this time running very slowly and using silent running. I was able to stay in Gibraltar harbour for 24 hrs, with no bother.

Much as I adore GWX I wish the escorts weren't such good listeners, especially early war. You can't go flank underwater within 4km of an escort sometimes. Late-war this is completely understandable (there are many cases of u-boats detected ahead of convoys purely by passive means) but early on during the happy times they could do with some ear plugs.

J

02-08-10, 05:04 PM	#1
JamesT73J Medic Join Date: Jan 2002 Location: United Kingdom Posts: 167 Downloads: 9 Uploads: 0	Resting on the bottom for a few hours.. Playing SH3 + GWX Gold and have dropped into the Med for a quick look at Gibraltar, late 1940. Got within a couple of km's of the port in absolutely foul weather at night; lots of traffic and escorts. My plan was to lie on the bottom overnight in about 70m of water, and have a peek through the periscope in the morning, then surface in the evening and sink some stuff. Bottoming out was easy enough, but after after about 6 hours an escort passed nearby and pinged me, and of course utterly trashed my sub once the charges came. I'm curious how I was detected. I realised too late that although I was at full stop, I hadn't chosen silent running. Is there enough noise from a submerged, still sub to allow passive sensor detection in SH3? Cheers James

02-08-10, 05:40 PM	#2
Submarine Torpedoman Join Date: Oct 2009 Location: USA Posts: 117 Downloads: 0 Uploads: 0	Water is one of the best transmitters of sound, and there are stories of ships picking up u-boat crew members talking and that is all they need. So without silent running, you are always screwed __________________

02-08-10, 10:43 PM	#4
Lord Biceps Watch Join Date: Dec 2009 Posts: 26 Downloads: 17 Uploads: 0	The game doesn't appear to recognize landforms in any other sense than that they can't be navigated through. In other words, the ship pinging you only finds your sub, not the land you're resting on, as if your sub had been floating freely in the water. You can also spot ships (and be spotted) through land. This caused quite a bit of trouble for me at Scapa Flow recently, as I was being bombarded by warships from several directions while being completely sheltered (or so I thought) by surrounding islands and coastlines, and not being able to even visually locate where the shots were coming from. This is a major annoyance for me, I hope they'll fix it in SH5 (or did they do that in SH4? I haven't played it yet). Last edited by Lord Biceps; 02-08-10 at 11:01 PM.

02-08-10, 11:40 PM	#6
krashkart Navy Seal Join Date: Jan 2010 Posts: 5,292 Downloads: 100 Uploads: 0	Hrm, good stuff to know. Accidentally engaged a destroyer (cough The game cheated, I swear!) and had to dive in a hurry. Very glad I remembered the silent running mode, I think it helped spare the sub and crew. Took a good thumping from the ashcans but was able to slip away. Just glad their gunners had bad aim. __________________ sent from my fingertips using a cheap keyboard

02-09-10, 02:31 PM	#9
Frank0001 Chief Join Date: Apr 2008 Posts: 317 Downloads: 16 Uploads: 0	I've had a few times where I'd wait on course of a fat convoy, silent running and engines off. The escorts would still pick me up if they're close enough. Sometimes they just sail happily by. __________________ Snipers of the Seas One eel - one Kill

02-08-10, 06:16 PM	#3
ryanglavin Samurai Navy Join Date: Jun 2009 Location: Evading that Hunter/Killer Group on my Tail Posts: 584 Downloads: 35 Uploads: 0	If you don't have silent running on (theoretically, you can't really prove this), the crew could still make all the noise and eat and walk around as much as they want.

02-09-10, 01:37 PM	#8
JamesT73J Medic Join Date: Jan 2002 Location: United Kingdom Posts: 167 Downloads: 9 Uploads: 0	I don't think the idea of a coastal ASW vessel being on constant sonar watch that strange; it's probably a standing order; I know they certainly were when on escort duty. It must be hard work with such a shallow environment with lots of traffic. Anyone try SH1? Coastal DD's used to ping constantly, and they usually detected you. I'm going to replay later trying the silent running method. If I'm detected passively I can only assume that there is some noise emission even on silent running. I come from SC / DW with the knowledge that all platforms emit noise all the time, to some extent, so it's merely a matter of the emitter being close enough to the listener before detection occurs; it was therefore highly unlikely that one could close on a vessel with listening gear unless acoustic conditions were very very bad.

02-09-10, 02:32 PM	#10
GREY WOLF 3 中国水兵 Join Date: Jan 2009 Location: Down deep avoiding drm attacks Posts: 284 Downloads: 33 Uploads: 0	Astic is A system using transmitted and reflected underwater sound waves to detect and locate submerged objects or measure the distance to the floor of a body of water. So with no sound at all it picks up THAT BIG MASS of metal in your case a sub. __________________

02-09-10, 04:05 PM	#11
Jimbuna Chief of the Boat Join Date: Feb 2006 Location: 250 metres below the surface Posts: 190,473 Downloads: 63 Uploads: 13	You need the cloaking device mod otherwise there is no way of hiding your presence. Stoooopid game engine __________________ Wise men speak because they have something to say; Fools because they have to say something. Oh my God, not again!!