ASDIC modelling in game

JuanLiquid · 06-16-20, 11:16 AM

I'm not sure if thermal layer are modelled either.

And about sea floor, in my last mission I was 3-5m over the sea floor at 240m of depth. And the still managed to ping me, I repeated, move the uboat to another location and I stopped again pretty close to the floor. Again pinged. 4-5 attemps later I desisted. They shoud have problems pinging me at the sea floor, right?

stellaferox · 06-16-20, 03:59 PM

Actually lying ON the seafloor gives some protection as I noticed. As long as it is the range of 150 - 200m

Catfish · 06-18-20, 07:54 AM

First, i have to admit i still have not played, but i will

As far as i read and followed the development, thermal layers have not been modelled yet.

Regarding ASDIC, from witness reports to what i read over decades i have some doubts about the accuracy and general effectiveness of ASDIC, at least until very late in the war. It is right that the systems got better over time, but most of escorts had an early type 141 or earlier on board, if at all. A lot of escorts did not have installed any.

Also it is unlikely to find a boat via ASDIC at periscope depth, for the same reason it could not be detected by it when surfaced. The ASDIC's detection cone for shallow swimming objects only works in very "special" environments, and mostly not even in completely calm seas. In most of the 50ies books about submarine detection this is still described as a big problem.
When waves are reflected from the ocean floor at shallow depths it is more likely, also a thermal layer can reflect upwards to meet a U-boat hull, and then being reflected back by already becoming inaccurate.
So even if the DE is lucky and gets a reflection from a certain direction, the real depth and distance are impossible to measure. If you think of atlantic waves and the general disturbance in the upper water column the chances for detection are small, to say at least. This has been modelled in some of the real old simulations.

If a boat still had been detected by active ASDIC at low depth, the contact would be gone by a distance of appx. 400 meters, from then on the DE would have to race to the last point of detection, guess where the boat turned to and at what speed, and also guess its depth.
Listening devices and ASDIC would also not work at higher speeds of course (which is why hedgehog and squid had been developed).
The DE also had to be quick to not become a victim of its own depth charge explosions.

The tactics and methods can be read quite accurately in C.S. Forester's "The good shepherd", though even this is highly optimistic for the time it is supposed to happen.

To make it short i doubt a boat at perisope depth could be detected by ASDIC in most circumstances

. If anyone finds a good report on that, i would like to read it.

stellaferox · 06-19-20, 04:32 AM

@Catfish

You are right. They couldn't detect U-boats on the surface or at periscope depth. That is how Kretschmer got detected. One of the crewmembers shouted ALARM and the U-Boat crashdived from the surface whilst on attack on a near convoy. That way the destroyers could find him. There is good material on that on YT.

It is not modelled well in the game, same as layers. At that time that knowledge wasn't widely used though. I am still waiting for some significant updates on the game. The last one being september last year. Since then there was only a login update (which we cannot notice) and the addition of morse, which nobody uses. They have been announcing Scapa Flow missions, chartupdates and more challenging gameplay since september 2019 but there is complete silence on the weekly updates from the DEV-team. Not a good sign for an Alpha game. UBOAT has been developing much faster and is really attractive nowadays. It is a pity as I like this game very much.

I fear for the further development of the game

Fidd · 07-01-20, 11:20 AM

I'd hesitate to ease to ease the risk of asdic detection, as in some ways this compels more realistic behaviour. For a start maintaining PD was not always easy, and so keeping to PD in daylight when hunted was a tactic with it's own risks. Firstly that part of the boat my accidently broach and be spotted, after which it was in for a very rough time, or, the much faster manoeuvering destroyers presented a risk of being rammed.

06-18-20, 07:54 AM	#3
Catfish Dipped Squirrel Operative Join Date: Sep 2001 Location: ..where the ocean meets the sky Posts: 17,799 Downloads: 38 Uploads: 0	First, i have to admit i still have not played, but i will As far as i read and followed the development, thermal layers have not been modelled yet. Regarding ASDIC, from witness reports to what i read over decades i have some doubts about the accuracy and general effectiveness of ASDIC, at least until very late in the war. It is right that the systems got better over time, but most of escorts had an early type 141 or earlier on board, if at all. A lot of escorts did not have installed any. Also it is unlikely to find a boat via ASDIC at periscope depth, for the same reason it could not be detected by it when surfaced. The ASDIC's detection cone for shallow swimming objects only works in very "special" environments, and mostly not even in completely calm seas. In most of the 50ies books about submarine detection this is still described as a big problem. When waves are reflected from the ocean floor at shallow depths it is more likely, also a thermal layer can reflect upwards to meet a U-boat hull, and then being reflected back by already becoming inaccurate. So even if the DE is lucky and gets a reflection from a certain direction, the real depth and distance are impossible to measure. If you think of atlantic waves and the general disturbance in the upper water column the chances for detection are small, to say at least. This has been modelled in some of the real old simulations. If a boat still had been detected by active ASDIC at low depth, the contact would be gone by a distance of appx. 400 meters, from then on the DE would have to race to the last point of detection, guess where the boat turned to and at what speed, and also guess its depth. Listening devices and ASDIC would also not work at higher speeds of course (which is why hedgehog and squid had been developed). The DE also had to be quick to not become a victim of its own depth charge explosions. The tactics and methods can be read quite accurately in C.S. Forester's "The good shepherd", though even this is highly optimistic for the time it is supposed to happen. To make it short i doubt a boat at perisope depth could be detected by ASDIC in most circumstances . If anyone finds a good report on that, i would like to read it. __________________ >^..^<*)))>{ All generalizations are wrong.

06-16-20, 11:16 AM	#1
JuanLiquid Machinist's Mate Join Date: Jun 2016 Posts: 130 Downloads: 60 Uploads: 0	I'm not sure if thermal layer are modelled either. And about sea floor, in my last mission I was 3-5m over the sea floor at 240m of depth. And the still managed to ping me, I repeated, move the uboat to another location and I stopped again pretty close to the floor. Again pinged. 4-5 attemps later I desisted. They shoud have problems pinging me at the sea floor, right?

06-16-20, 03:59 PM	#2
stellaferox Soundman Join Date: Nov 2007 Posts: 142 Downloads: 51 Uploads: 0	Actually lying ON the seafloor gives some protection as I noticed. As long as it is the range of 150 - 200m

06-19-20, 04:32 AM	#4
stellaferox Soundman Join Date: Nov 2007 Posts: 142 Downloads: 51 Uploads: 0	@Catfish You are right. They couldn't detect U-boats on the surface or at periscope depth. That is how Kretschmer got detected. One of the crewmembers shouted ALARM and the U-Boat crashdived from the surface whilst on attack on a near convoy. That way the destroyers could find him. There is good material on that on YT. It is not modelled well in the game, same as layers. At that time that knowledge wasn't widely used though. I am still waiting for some significant updates on the game. The last one being september last year. Since then there was only a login update (which we cannot notice) and the addition of morse, which nobody uses. They have been announcing Scapa Flow missions, chartupdates and more challenging gameplay since september 2019 but there is complete silence on the weekly updates from the DEV-team. Not a good sign for an Alpha game. UBOAT has been developing much faster and is really attractive nowadays. It is a pity as I like this game very much. I fear for the further development of the game

07-01-20, 11:20 AM	#5
Fidd Captain Join Date: Apr 2005 Location: Blighty! Posts: 542 Downloads: 10 Uploads: 0	I'd hesitate to ease to ease the risk of asdic detection, as in some ways this compels more realistic behaviour. For a start maintaining PD was not always easy, and so keeping to PD in daylight when hunted was a tactic with it's own risks. Firstly that part of the boat my accidently broach and be spotted, after which it was in for a very rough time, or, the much faster manoeuvering destroyers presented a risk of being rammed.