PDA

View Full Version : DD's Sensors ........



Redwine
07-02-2004, 07:58 AM
It is an important point to discuss to have a real behavior........

DD's sensors capability changes lot of during the war.........

Kapitan Kretschmer use the surface attack at early war due to the reduced capability of DD's sensors, he introduce his sub into the convoy on surface........

In some situation his sub pass between the escorts at very few distance, at night and they can not to detect the sub..........

Some times at une miles of the escorts, and in some situations between two escorts separated one mile, half mile to each one and they can not detect the sub.........

This situation are described many times in the book of Terence Robertson..........


How many factors affect the DD's capability......?

In his own Rulers manual write by Kpt. Kretschmer, he wote the sub must to attack from the dark side of the convoy, it is the oposit side of the moon......... this prevents the merchants wards to watch the sub silouete.......

He wrote, if no moon, the sub must to attack from the wind side, the merchant's wards was lower effective watching with the wind in his face........

Night was a very good cover almost at early war.........

Visual detection, even at clear day was so dificoult too............due to the reduced silouete of the sub........

Pasive sensor are less effective when the sub runs in surface, sound propagation along the surface is not so good.......

Terence Robertson afirm, the ASDIC was unutil if the sub was on surface....... and it is less effective even at periscope depth......

When you run into the convoy, it is very dificoult to escorts to detect you by radar, or pasive or active sonar......... because the radar has multiple echos from the ships of the convoy, and the background noise covers you...........

For those I had read, ASDIC has a efective range from 800 m at early war up to so so 1500 m at later times..........

A sub runing at silent run, and under the thermal layer was very hard to be detected..... near to imposible with pasive sensors and so hard with asdic..........

Backgrouynd noise has very influence over detction capabilities........

Background noise can be produced by ships runing near, depth charges explosions, hevy waves on surface, rain, or storms, wave on rocks at shores and many other factors.........

Will be interesting to discuss all this factors, to learn about the reality, I am not an expert........and better if they will be modelated........

Well, for those interested, discussion is open......

Best regards to all.........

______________________________
.
http://personales.ciudad.com.ar/pietraroja/imagenes/firmas/EscudoU552b.jpg
.
The Ancient History of the Submarine
"Subgenesis" (http://www.iespana.es/Subgenesis/subgenesis/sg00.htm)

Manual TDC
"HTDC Tutorial" (http://www.iespana.es/rotteufel/htdc_tutorial/a_start.htm)
.

Redwine
07-02-2004, 07:58 AM
It is an important point to discuss to have a real behavior........

DD's sensors capability changes lot of during the war.........

Kapitan Kretschmer use the surface attack at early war due to the reduced capability of DD's sensors, he introduce his sub into the convoy on surface........

In some situation his sub pass between the escorts at very few distance, at night and they can not to detect the sub..........

Some times at une miles of the escorts, and in some situations between two escorts separated one mile, half mile to each one and they can not detect the sub.........

This situation are described many times in the book of Terence Robertson..........


How many factors affect the DD's capability......?

In his own Rulers manual write by Kpt. Kretschmer, he wote the sub must to attack from the dark side of the convoy, it is the oposit side of the moon......... this prevents the merchants wards to watch the sub silouete.......

He wrote, if no moon, the sub must to attack from the wind side, the merchant's wards was lower effective watching with the wind in his face........

Night was a very good cover almost at early war.........

Visual detection, even at clear day was so dificoult too............due to the reduced silouete of the sub........

Pasive sensor are less effective when the sub runs in surface, sound propagation along the surface is not so good.......

Terence Robertson afirm, the ASDIC was unutil if the sub was on surface....... and it is less effective even at periscope depth......

When you run into the convoy, it is very dificoult to escorts to detect you by radar, or pasive or active sonar......... because the radar has multiple echos from the ships of the convoy, and the background noise covers you...........

For those I had read, ASDIC has a efective range from 800 m at early war up to so so 1500 m at later times..........

A sub runing at silent run, and under the thermal layer was very hard to be detected..... near to imposible with pasive sensors and so hard with asdic..........

Backgrouynd noise has very influence over detction capabilities........

Background noise can be produced by ships runing near, depth charges explosions, hevy waves on surface, rain, or storms, wave on rocks at shores and many other factors.........

Will be interesting to discuss all this factors, to learn about the reality, I am not an expert........and better if they will be modelated........

Well, for those interested, discussion is open......

Best regards to all.........

______________________________
.
http://personales.ciudad.com.ar/pietraroja/imagenes/firmas/EscudoU552b.jpg
.
The Ancient History of the Submarine
"Subgenesis" (http://www.iespana.es/Subgenesis/subgenesis/sg00.htm)

Manual TDC
"HTDC Tutorial" (http://www.iespana.es/rotteufel/htdc_tutorial/a_start.htm)
.

bertgang
07-02-2004, 09:41 AM
As I know, underwater detection systems didn't change very much during the war.

Passive sonar was quite useless near convoys, as the greatest noise was done by surface ships.

Asdic loosed the target during attacks, an effect of DD moving and noise by depth charges.
Later, this problem was solved using a new tactic; an escort had only to fix the target by asdic, sending messages to attacking fellows.

Technical advancements were reached mostly in surface detection; the radar, obviously, but the radio signals finder too.

When the mix of radar and air patrols forced the subs to stay submerged, they went out of businness.

Hitman_PAces
07-02-2004, 10:21 AM
Yes, that´s basically the same info I have , Redwine http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

The main role of escorts during the war was forcing the subs to stay underwater, where their slow speed and limited vision reduced the attack chances. Killing subs with DCs was just a luxus, and normally an unexpected success.

I´m reading now "Black May", a Book that describes well what changed in May 1943 to make things so hard, and basically it was the higher number of escorts per convoy and intercept devices of surface communications, as well as radar what helped the Allies repulse the subs.

But kills were normally achieved by locating and surprising a sub on surface in the fog, so that if DCs were dropped, it was when the sub was diving and still at shallow depth.

DCing a sub that dives very deep is nearly impossible unless you manage to put together a group of threee DDs. Instead, the common ttechnique was to DC her and wait till batteries were exhausted and she had to surface. But that was done only in later times, when sub hunt groups were created.

Cheers

Redwine
07-02-2004, 10:57 AM
Hitman :

Where did you buyed that book Hitman ?

I will go to Madrid this month, is it abilable in any book store there ?

Bertgang :

With all respect for your opinion, I read detection systems was increasig their capabilities with the advance of the war....... I read, ASDIC has below 800m at first time and rise up up to about 1400/1500 m at last months of the war.......

Periscopes was not detectables by radar at first times but was dtectables at later times.......

Kapitan Otto Kretschmer break the rulers of attack of the submarine school, attacking on surface at 1940 and 1941 with very successful results, taking advantages of this low capabilities at early times.......

He knows whatt HITMAN is saying, submerged he has very low speed and maneubrability, at surface he is limited by these disadvantages........

I read this was not posible at later times.............

______________________________
.
http://personales.ciudad.com.ar/pietraroja/imagenes/firmas/EscudoU552b.jpg
.
The Ancient History of the Submarine
"Subgenesis" (http://www.iespana.es/Subgenesis/subgenesis/sg00.htm)

Manual TDC
"HTDC Tutorial" (http://www.iespana.es/rotteufel/htdc_tutorial/a_start.htm)
.

bertgang
07-02-2004, 11:26 AM
Redwine, we are saying quite the same with different words.

ASDIC power was doubled during the war, but it wasn't the key factor.

Radar is different; it's a surface detection device, even when detecting periscopes.

Surface and air control by Allies defeated the U-Boots; underwater detection was less important

Redwine
07-02-2004, 01:38 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Bertgang:

Surface and air control by Allies defeated the U-Boots; underwater detection was less important<HR></BLOCKQUOTE>

I think so the same as you.........

About the radar detection of the periscope, it must to be reduced in heavy seas........ I am wrong ? It will be exposed only by short lapse of time and continuous coverd and un covered by the sea waves .......... This must to reduce the hability to detect a periscope in surface ........ It is correct ?

______________________________
.
http://personales.ciudad.com.ar/pietraroja/imagenes/firmas/EscudoU552b.jpg
.
The Ancient History of the Submarine
"Subgenesis" (http://www.iespana.es/Subgenesis/subgenesis/sg00.htm)

Manual TDC
"HTDC Tutorial" (http://www.iespana.es/rotteufel/htdc_tutorial/a_start.htm)
.

Bruno_Lotse
07-02-2004, 02:39 PM
I would be nice if the devteam would model both sky and attack periscopes. It is a sky periscope that can be easily popped up, check your target, retract to avoid detection. Attack periscope is another matter. Correct me if I am wrong but the height of that thing was fixed and to raise it higher over the surface or hide it below the surface to avoid detection the crew had to change depth of the boat. I also think it should be more difficult to pick up scope in rough seas. However, it should be more difficult yet still possible. Remember Das Boot scene when the Old Man was hunting British DD in rough seas. He was absolutely sure they could not see his attack scope. Yet they did. What was it - radar, damn good look-out watch on the British DD, or just dumb luck? Who knows. They fact is they evidently saw them. It would be nice to have this kind of uncertainty in the sim.

Bruno Lotse
U743

HeibgesU999
07-02-2004, 02:49 PM
Will they model both powered and manual periscopes?

Bruno_Lotse
07-02-2004, 03:12 PM
What is it - 'manual periscope'?
I think all scopes on German boats were powered. Only in the case of sky scope they used power of transmission gear to raise it or retract it, and in the case of attack scope - the power of boat herself. You want higher - means boat should go up, lower - boat goes down.
Bruno Lotse
U743

HeibgesU999
07-02-2004, 04:48 PM
herber werner, in iron coffins, describes how pissed off he was that his first command had a manual scope, and hope tough it was to wrestle with. rather like trying to parallel-park a car with manual steering i imagine.

Redwine
07-02-2004, 06:19 PM
Kapitan Johannes Spiess (WW1) tells in his book "The Submarine War" the hardest job of the attack was to move the periscope, he need the help of his First Officer to move it.......

He finished tired after some time moving it........

______________________________
.
http://personales.ciudad.com.ar/pietraroja/imagenes/firmas/EscudoU552b.jpg
.
The Ancient History of the Submarine
"Subgenesis" (http://www.iespana.es/Subgenesis/subgenesis/sg00.htm)

Manual TDC
"HTDC Tutorial" (http://www.iespana.es/rotteufel/htdc_tutorial/a_start.htm)
.

Bruno_Lotse
07-02-2004, 06:52 PM
OK. 'Iron Coffins' is my desk-book as well.
Evidently they used to have modern models and some vintage ones - all the way from WW1. Here how Werner describes his experience with scope on U-415:
'The periscope in the tower was one of the earliest designs. I was accustomed to a fully automatic tube equipped with swivel seat, electric drive, numerous gadgets, and in integrated computer system. But to use this prehistoric scope, one had to squat to look around through its eye-piece; and following the up-and-down movements of the long shaft would be an acrobatic exercise' (Ch.19, Desaster and Defeat)
Well, I would dream that SH2 be modeled in such a way that we have all those kinds of scopes. You used to work with advanced piece then they transferred you to another boat - BAM!!! you stuck with granddaddy of all U-boat eyepieces! I do not like idea of selecting equipment. Not realistic. I would like to get in the sim what I am ordered to get - just like Werner on U-415.

Bruno Lotse
U473

HeibgesU999
07-02-2004, 06:55 PM
I think what really killed the uboats was the enigma deciphering. In the uboat commanders handbook, in all the messges kalue's were required to send, their exact postition is one of the required message line. A lot more exact then any huff-duff .

Bruno_Lotse
07-02-2004, 07:24 PM
German BD (Beobachtung-Dienst) was very successful in breaking British naval code. In 1939 Germans knew exact position of every British warship. Did it help them. Not very much. OK. You know position. Yet you have to get there, find the guy, and actually sink him.
To bring UBooten out of business, in my view, we need three things: a tool to find a boat on the surface (90% of their time they were on the surface), i.e.radar, you need a tool to deliver a killing blow - plane, and you need a platform to deliver that tool at any point in the ocean- air-carrier. If you have all three elements in place in sufficient numbers - why bother with decyfering? Incidentally, Allied powers were in great concern (if not to say in panic) when they learned about Type XXI program. They could decyfier Enigma. But if the boat is 90% of its operational time is submerged then now - what?

Bruno Lotse
U473

HeibgesU999
07-02-2004, 08:51 PM
due to the speed of the submarine, and its mission, knowing the exact location of a British or American warship would be less usefull to them. even knowing the the exact location, course, and speed of a slower moving convoy would allow only uboats in a certain operational area to attack at all.

but the Allies, with huge ASW assets to work with, if they knew the location of the submarine could vector those forces into the the proper area, and then their radars and what not allowed them to pinpoint the location of the slow moving uboat. i suppose the Allies had enough planes where they would have allocated whatever was neccessary, but I have to think that a lot fewer uboats would have been discovered by aircraft in the first place if the German codes had not been compromised.

If BdU had only not required boats to report their own position in the different reports. it would leave him with a little less information, and who is to say what effect this would have had.

and in the US Army today, you never send your position using any kind of coordinates (only reference to operational graphics)