[WIP] Realistic Hydrophone

[THE_MASK]

Originally Posted by gap

aren't blind spots stored separately for each hydrophone in its own SensorData controller?

I was referring to the known issues on post 1 .

[gap]

Originally Posted by sober

I was referring to the known issues on post 1 .

Yes, I got your point sober. I think tscharlii's note on post #1 refers to signal strength and bearing accuracy curves rather than to blind angles, but indeed I can be wrong. Let's wait for his answers

[tscharlii]

Originally Posted by sober

So if i am using the rotating hydrophone , i have blind spots ?

As of Version 1.1, that is true. Adding support for the rotating hydrophone KDB and the Balcony Apparatus, however, is on the todo list.

Some aspects of the KDB/Balcony are not clear to me, yet. Probably you can help me out here.

As my understanding of the KDB is right now, I would model it just like the GHG, just without a deaf area at the bow and without a bearing dependent accuracy/max range degradation.

But what about the deaf area at stern. It stems from the engine noise, right? The conning tower doesn't seem to be much of an obstacle to the KDB (for instance see http://www.u47.org/images/album/R07_6jul40.jpg , KDB sensor is visible on the very bottom left of the picture).
So would it be possible to listen to contacts at stern, if you shut down the engines while being submerged?
Another source (which I cannot find again now ), however, mentioned, that you'd never completely shutdown your engines while being submerged. The sub would start sinking slowly, and change its position unpredictably, which can result in dangerous situations. So we might assume, there is always enough noise at stern, that we cannot listen there using the KDB?

On to the Balcony apparatus:

http://www.uboataces.com/hydrophones.shtml
The Balkon Great (Balcony Apparatus) was an improved version of GHG. Where the previous had 24 hydrophones, the Balkon had 48 hydrophones and improved electronics, which enabled more accurate readings to be taken.

So: Better bearing accuracy than the GHG/KDB, and like the KDB, no deaf area at bow and no bearing dependant degradation due to the way the hydrophones were mounted on the sub.
The german wikipedia article on the GHG (http://de.wikipedia.org/wiki/Gruppenhorchger%C3%A4t) also states, that you could use the balcony apparatus while the sub was surfaced, because the hydrophones were mounted at the keel and the body of the sub shielded them from surface noise. Unfortunately the wikipedia article provides no source for this statement and I couldn't confirm it anywhere else yet. Also, the UBoot_Sensors.sim file of R.E.M_by_Xrundel_TheBeast_1.2 - no hyd on surface - NewUIs-IRAI compatible (gap, your work?) seems to require the boat to be submerged, even with a balcony apparatus.

[gap]

Originally Posted by tscharlii

As of Version 1.1, that is true. Adding support for the rotating hydrophone KDB and the Balcony Apparatus, however, is on the todo list.

Does it mean that your code doesn't read valid bearing ranges from SensorData controllers? For future moddability, it would be better if you inferred optimal and deaf angles from the values stored separately for each hydrophone in its own controller(s).

Originally Posted by tscharlii

Some aspects of the KDB/Balcony are not clear to me, yet. Probably you can help me out here.

To the best of my knowledge:

- the KDB had a much shorter range than the GHG, but it had a better bearing accuracy, and had no deaf angles. From that, I desume that it could have been more sensitive to short wavelenghts and lesser sensitive to long wavelenghts than the GHG, but this is just my speculation.

- due to its short range, the KDB wasn't used as unique listening apparatus, but always coupled with the GHG. This is currently not modelled in game (KDB's specs are therefore unrealistically boosted in game) but there is a possible method for making both sensors to be associated with the KDB upgrade. If you want, I can send you some files modded to the above purpose. I am not fully sure that my method would work, but imo it is worth a test.

- due to their relative vicinity, running engines should have deteriorated hydrophone sesitivity and accuracy at any angle, maybe with a slight further decrease in performamnce when listening astern. Balcon Gerat's sonic filters could have partly obviated the problem, but even so silent running or full stop would have been an important listening prerequisite.

- both GHG's and balcon gerat's sensors were located along or near boat's keel and, theoretically, they could have been used on surface, though the vicinity of wave-generated noise, would have deteriorated their performance sensibly. Again, Balcon Gerat's improved electronics could have made surface listening a bit better. On the contrary, KDB's sensors stickied out of the water while the boat was surface, thus making their usage impossible.
NOTE: the SensorHeight parameter (SensorData controller), already takes into account sensors' position along the boat profile. Therefore, setting KDB's minimum heigh lower than GHG's makes little sense imo.

- I remember having read on the forum that the Balkon Gerat had a deaf spot at high elevation angles (thus making its use pointless against targets located directly on top of the boat). IIRC, this fact is already modelled in game through stock and REM settings. I couldn't find a conformation to the above statement elsewhere on the web, but it makes sense anyway as, being located below the keel, BalkonGerat's sensors were a bit lower than GHG's sensors, and much lower than KDB one. This would be yet another argument in favour of the assumption that the Balkon Gerat wasn't as affected as GHG and KDB by surface noises.

Originally Posted by tscharlii

R.E.M_by_Xrundel_TheBeast_1.2 - no hyd on surface - NewUIs-IRAI compatible (gap, your work?) seems to require the boat to be submerged, even with a balcony apparatus.

Yes, by popular request I modded REM's settings according to New UI's no hydrophone on surface submod. This doesn't mean that those settings are accurate, but rather that many players got accustomed to them.
In my opinion you should create a new set of sensordata controller settings, suiting your mod better. If you wanted to increase compatibility with other mods, you would need to clone the existing hydrophones. Should you decide to follow my suggestion, I will be glad to help you on the clonig task

[THE_MASK]

Any way to script Mr know it all to announce depth charges in the water ? It should be Mr almost know it all

[gap]

Originally Posted by sober

Any way to script Mr know it all to announce depth charges in the water ? It should be Mr almost know it all

Good idea

[tscharlii]

Originally Posted by gap

Does it mean that your code doesn't read valid bearing ranges from SensorData controllers? For future moddability, it would be better if you inferred optimal and deaf angles from the values stored separately for each hydrophone in its own controller(s).

Agreed, it would be better. There are some technical issues: How to access these values from python script in the first place? What to do, if you make a UBoot_Sensors.sim with multiple sensors of the same type (like in REM), but with different deaf zones? So it requires a certain amount of effort to make this work universally. The benefit, on the other hand, is limited imho. The deaf zones of the different hydrophones are well documented by different sources, and thus I do not expect further changes here. So I'll probably keep it this way for now.

Originally Posted by gap

- the KDB had a much shorter range than the GHG, but it had a better bearing accuracy, and had no deaf angles.

Do you have any source for me talking about the KDB's shorter range/better accuracy? I can't seem to dig one out. Some numbers would be cool. I agree there should be no deaf angle at all. What's the reasoning for having one at stern in UBoot_Sensors.sim for the KDB?

Originally Posted by gap

- due to its short range, the KDB wasn't used as unique listening apparatus, but always coupled with the GHG. This is currently not modelled in game (KDB's specs are therefore unrealistically boosted in game) but there is a possible method for making both sensors to be associated with the KDB upgrade. If you want, I can send you some files modded to the above purpose. I am not fully sure that my method would work, but imo it is worth a test.

My email: tscharlii@gmx.de

Originally Posted by gap

Yes, by popular request I modded REM's settings according to New UI's no hydrophone on surface submod. This doesn't mean that those settings are accurate, but rather that many players got accustomed to them.
In my opinion you should create a new set of sensordata controller settings, suiting your mod better. If you wanted to increase compatibility with other mods, you would need to clone the existing hydrophones. Should you decide to follow my suggestion, I will be glad to help you on the clonig task

That's probably the way to go: My Mod needs relatively simple hydrophone sensor controllers in UBoot_Sensors.sim, just one per hydrophone type:
- GHG: Maxrange 40000, MinDepth 6m, Bearingranges: 10-150, 210-350
- KDB: Maxrange 30000 (or whatever shorter range means), MinDepth 10m (or deeper? the kdb sensor should be well below the surface), Bearingranges: 0-360
- BG: Maxrange 50000, Mindepth 0m, Bearingranges: 0-150, 210-360

The rest will be done by scripting: Consider the sensor controllers as a first set of criteria, whether we can hear a contact or not, and the scripts act as a secondary filter, after the contact has been detected by the sensor controller.
For instance, this is GHG's effectiveness by our sub's depth (x-axis: depth in meter, y-axis: GHG-effectiveness in percent):



So at 6m it starts working, at 7m we can already hear (very loud) contacts in a distance of 4km (10% of 40km set in sensor controller), and at 30m we reach an effectiveness of 95%, i.e. we can hear very loud contacts in a distance of 38km.

There are other depth modifiers for KDB, BG, and gradual modifiers that take the contact's speed into account (enlarging the detection range for loud contacts, shrinking it for more silent contacts), as well the noise generated by our own engines: We cannot hear anything, if we are running on diesels (incl. snorkeling), it's just too loud. On electric engines, silent running doesn't interfere much with the hydrophone's effectiveness, but moving at flank speed shrinks the detection range to just a few hundred meters.

So: It'd be great, if you could help me mod the UBoot_Sensors.sim. The goal is to have the above simple hydrophone sensors, but keep other changes/fixes, that are applied by REM, IRAI etc.

[tofoftofof]

Seems like the 1.1 version manually replaced sounds over to German? Tried preventing that by uninstalling mod, removing the sounds folder from the mod, reinstalling only to end up with no sonarman sounds. Nowhere near as interesting as the technical details in the posts preceding mine - but hopefully an easy fix.

[gap]

Originally Posted by tscharlii

Agreed, it would be better. There are some technical issues: How to access these values from python script in the first place?

No idea, sorry. Probably only TDW could help you on it. Haven't you found any example within his scripts? Try looking into IRAI

Originally Posted by tscharlii

What to do, if you make a UBoot_Sensors.sim with multiple sensors of the same type (like in REM), but with different deaf zones?

You could interpolate among them. Imo we should have maximum two SensorData controllers per hydrophone, for setting min and max depths/detection ranges. The rest should be done by scripts, based on the values stored in the aforementioned controllers.

Originally Posted by tscharlii

So it requires a certain amount of effort to make this work universally. The benefit, on the other hand, is limited imho.

Besides being probably a cleaner approach (but this is just my opinion), using SensorData values would allow better future moddability, even by people who don't know python. A good alternative could be storing all the new values in a external cfg file, similar to what TDW has done with many of his mods. This would enable you to make your hydrophone scripts pretty generic, thus reducing your workload and enhancing the configurability of your mod.

Originally Posted by tscharlii

Do you have any source for me talking about the KDB's shorter range/better accuracy? I can't seem to dig one out. Some numbers would be cool.

sure:

uboataces.com

Gruppenhorchgerat (GHG)

The standard U-boat hydrophone, the GHG (Group Listening Apparatus) was installed in U-boats from 1935 onwards. It consisted of two sets of hydrophones mounted on each side of the bows, covering two arcs of 140 degrees on the sides of the U-boat. Because the hydrophones could not be rotated, the triangulation was most effective with sound sources coming from the sides, with deteriorating accuracy as the source moved to the front or rear of the boat. Consisting of 24 hydrophones, the GHG could pick up lone vessels up to 20 kilometers and convoys up to 100 kilometers away. The detection range however was also dependant on sea conditions.

Kristalldrehbasisgerat (KDB)

The KDB (Crystal Rotating Base Apparatus) was an improvement of the GHG in that it was rotatable and hence able to provide more accurate readings from any direction. The disadvantage however was its extreme vulnerability to depth charges.

Balkon Gerat

The Balkon Gerat (Balcony Apparatus) was an improved version of GHG. Where the previous had 24 hydrophones, the Balkon had 48 hydrophones and improved electronics, which enabled more accurate readings to be taken. The Balkon was standard on the Type XXI and was also fitted to several Type VIIs.

David Miller, 2000 - U-boat History, Development and Equipment, 1914-1945 (p. 105):

GRUPPENHORCHGERÄT (GHG)
The GHG (= group listening device), which was installed in U-boats from 1935 onwards, consisted of a group of hydrophones, which were mounted in two arcs, one on each side of the bows. Each hydrophone was connected to an electronic timing circuit in the Funkraum where the operator made adjustements to obtain the maximum reading, enabling him to establish the direction of the source. The GHG originally had 11 hydrophones each side, but this was later increased to 24 to give greater sensitivity and accuracy. However, the hydrophone arrays were fixed, which meant that the system was most effective when dealing with sound sources on the beam and its accuracy decreased rapidly with sources ahead or astern. The range depended on the ambient acoustic properties of the water but, given favorable conditions, single ships could be detected at about 11nm (20km) and convoys about 54nm (100km).

KRISTALLDREHBASISGERÄT (KDB)
The KDB (=crystal rotating base device), which was installed in Type VIICs and Type IXCs, was introduced in an effort to improve on the performance of the GHG and could give a reading with an accuracy, under favorable conditions, of ±1 degrees. The sensor itself was T-shaped; the cross-piece, some 19.7in (500mm) long, contained six crystal receivers. The KDB was located on the upper casing just forward of the capstan and could be rotated from within the U-boat. It suffered from two disadvantages: it could not be used when the U-boat was travelling at high speeds and it was vulnerable to damage from depth charges.

BALKON GERÄT
The Balkon Gerät (= balcony apparatus), usually known simply as 'Balkon' was an improved version of the GHG, and was first tested in a Type IXC in 1943. This was a cylindrical device installed at the foot of the stem, in which 48 hydrophones were installed. Coupled with greatly improved electronics, this gave a major improvement in performance compared to the GHG, and covered an arc ±170 degrees. Balkon was a standard fit in the Type XXI and was also installed in a small number of Type VIICs in 1944-45. Range varied with speed, weather, and sea-state but, as a guide, was stated to be 10,840yd (10,000m) against destroyers and 6,500yd (6,000m) against merchant vessels, with an accuracy of ±2 degrees.

German A/S Vessel "UJ 1404" - Interrogation of Survivors - C.B. 4051 (49), September 1942

(xi) Types of Listening and Search Gears
(A) Listening Gears

[...]

(c) G.H.G. ("Gruppenhorchgerät"). Consists of up to ninety hydrophones on either bow arranged elliptically. There are a number of circuits used in conjunction with condensers and the hydrophones are automatically switched in order to obtain bearings as a handwheel is rotated round a dial marked from 0-360°.

(d) K.D.B. ("Kristalldrehbasis") The K.D.B. gear consists of six receivers in line under the ship, which can be rotated from 0-360. The gear can pick up ships at a range of between 10-15 kms. (6.2-9.3 miles), giving their bearing to the nearest degree. It can be used up to a speed of 21 knots, but its range would be limited owing to propeller noises. The K.D.B. is made up of basis and crystal receiver, amplifier, filter and headphones. It operates on 220 volts and the shaft can be lowered about 50 cm. (19.6 ins.) below the ship.

REPORT ON THE INTERROGATION OF SURVIVORS FROM U-118 SUNK ON 12 JUNE 1943 - O.N.I. 250 – G/Serial 15 (Op-16-Z), 26 August 1943

K.D.B.

A survivor of U-118 said that the German Naval High Command had ordered the Krystaldrehbasis (quartz hydrophone) removed from all U-boats, but this was being done only as time permitted. The same survivor, a radio petty officer, said he liked the K.D.B. because he considered it more accurate than the other hydrophones, even though it’s range was not as wide.

"U 340" - Interrogation of Survivors - C.B. 04051 (91), January 1944

(v) K.D.B. Hydrophones no longer fitted to Operational U-Boats

A prisoner from "U 135" still under interrogation said that K.D.B. hydrophones are no longer fitted to operational U-Boats, as it is impossible to make the detection units watertight at depths greater than 100 metres (328 ft.). The prisoner added that the K.D.B. is a much better instrument at short and medium ranges than the G.H.G., and at very short ranges will give a bearing when G.H.G. will not. However, at long ranges, there is no reception, and the G.H.G. is therefore essential.

"U 73" - Interrogation of Survivors - C.B. 04051 (95), February 1944

(ix) K.D.B. Search Gear
The prisoner from "U.J.2104" stated that in A/S vessels, the K.D.B. search gear consists of six crystal units about 10 cm. (3.9 in.) in diameter, mounted in a single row on a retractable mounting about 90 cm. (35.4 in.) in length. The extensible gear is trained to receive the maximum sound effect in earphones. Bearing can be obtained within 5°. The gear is easily damaged and, at high speed, the rushing of water makes reception very poor (see C.B. 04051(49) ). Among associated gear, a special converter supplies a six valve amplifier. The valves were a special type, about 2 in. high.

Interrogation of U-Boat Survivors - Cumulative Edition - C.B. 04051 (103), June 1944

(v) Hydrophones.

There are two principal types (Fact):

(a) G.H.G. (Gruppenhorchgerat") Multiple Unit Type. Generally consists of 24 hydrophones grouped 12 on either bow, but may consist of 36 or 48 hydrophones. To obtain bearings a handwheel is rotated over 360 degrees. Range: Up to 20 miles under favorable conditions. G.H.G. is fitted in all U-boats.

Bearing accuracy is good. The maximum range at which a destroyer or small merchantman can be heard under good Atlantic condition is said to be 10 miles and convoys may be heard up to 20 miles. Under poor conditions, however, the range drops to half or less of these figures. It is vulnerable to depth-charge attack and many C.O.'s distrust it.

(b) K.D.B. ("Kristall Dreh Basis"). Six receivers in line in a rectangular frame, rotatable through 360 degrees. Range is limited. Though formerly fitted in all U-boats, it is being discarded since water noises render it useless except at the slowest speed, and if the U-boat dives beyond 300 feet it is liable to be flooded. At short ranges, however, it is more accurate than the G.H.G. gear. It was mounted on the upper deck forward.

Another book, The encyclopedia of U-Boats by Eberhard Möller and Werner Brack, also deals with the hydrophone topic; the paragraph 'Underwater Passive reception (Listening)', discusses several aspects of WWII German listening gears. The following facts are reported:

sound spectrum sensitivity of all the sensors:
1,000-15,000 Hz

KDB's pros and cons:
"after swinging the device out [the authors refer probably to the device fitted aboard surface vessels, which was retractable], the base was rotated either by hand or remote control; and by moving it back and forth a noise source could be located with an accuracy to within a few degrees by searching for the maximum volume. By swithching on electric filters it was possible to suppress the lower frequencies and get more accurate readings by allowing the higher frequencies through"; nonetheless, it also stated that "because of noise from the current generated by the movement through the water, at first it could only be used at speeds of up to 6 knots, but improvements came later when it was encased in a streamlined casing."

GHG's pros and cons:
"the problem of obtaining good reception at high speed could only be solved by installing groups of receivers permanently into the hull plating or into special housings at the bow or along the keel". On the other hand "whereas they proved to be very accuate for diagonal readings, these straight-line receiver groups [the GHG sensors] had the disadvantage of offering very inaccurate results for readings from bearings forward or astern".

GHG's optimal ranges and accuracy:
"given favourable 'acoustic weather', a U-boat in 'silent' mode could pick up noise at the following ranges:
A destroyer cruising at 20 knots and at a range of 6-12nm with an accuracy of 1 degree
A merchantman moving at a speed of 10 knots and at a range of 4-8nm to the same accuracy; and Convoys from a far greater distance".

Balkony Apparatus pros and cons:
"the 'balcony' introduced later on U-boats originated with a demand by Oberkommando der Marine to make it also possible for surfaces, as well as submerged U-boats to 'listen'. This shape permitted continuous direction-finding with approximately the same accuracy in all arcs apart from the sector aft between 150 and 210 degrees.
The increase in cruising and maximum speeds brought about by the Type XXI and XXIII U-boats, as well as by the Walter (Type XVII and XXVI) boats, saw the 'balcony' arrangement installed behind the hull plating and faired over as smoothly as possible, the receiver working through a 3mm thick cover of V2A steel sheeting"".

On a slightly unrelated note, at least in the Mediterranean the optimal listening depth was between 60 and 80m under the sea level; sources:

REPORT ON INTERROGATION OF SURVIVORS FROM U.331, A 500-TON U-BOAT, SUNK AT ABOUT 1430 ON 17th NOVEMBER, 1942.

(ix) Hydrophones. G.H.G.
Operators found 80 metres (164 ft.) the best listening depth in the Mediterranean.

REPORT ON THE INTERROGATION OF SURVIVORS FROM U-409 SUNK 12 JULY 1943 - Final Report - G/Serial 24 (Op-16-Z)

U-BOAT TACTICS IN THE MEDITERRANEAN

U-409 was assigned to an operational area on the known convoy route near Oran. During daylight hours she could listen submerged at a depth of about 60 meters. One prisoner stated that other boats in the Mediterranean customarily maintain a depth of about 80 meters.

Originally Posted by tscharlii

I agree there should be no deaf angle at all. What's the reasoning for having one at stern in UBoot_Sensors.sim for the KDB?

The astern deaf angle has been in KDB's settings since SHIII, I think, and no one has complained about it so far. Going by logic, the conning tower could have posed an obstacle to the detection of far or medium distance sound sources; Yet, none of the sources I have consulted makes any mention of it.

Originally Posted by tscharlii

My email: tscharlii@gmx.de

Tomorrow I will send you a testing patch

Originally Posted by tscharlii

That's probably the way to go: My Mod needs relatively simple hydrophone sensor controllers in UBoot_Sensors.sim, just one per hydrophone type:
- GHG: Maxrange 40000, MinDepth 6m, Bearingranges: 10-150, 210-350
- KDB: Maxrange 30000 (or whatever shorter range means), MinDepth 10m (or deeper? the kdb sensor should be well below the surface), Bearingranges: 0-360
- BG: Maxrange 50000, Mindepth 0m, Bearingranges: 0-150, 210-360

The rest will be done by scripting: Consider the sensor controllers as a first set of criteria, whether we can hear a contact or not, and the scripts act as a secondary filter, after the contact has been detected by the sensor controller.
For instance, this is GHG's effectiveness by our sub's depth (x-axis: depth in meter, y-axis: GHG-effectiveness in percent):



So at 6m it starts working, at 7m we can already hear (very loud) contacts in a distance of 4km (10% of 40km set in sensor controller), and at 30m we reach an effectiveness of 95%, i.e. we can hear very loud contacts in a distance of 38km.

There are other depth modifiers for KDB, BG, and gradual modifiers that take the contact's speed into account (enlarging the detection range for loud contacts, shrinking it for more silent contacts), as well the noise generated by our own engines: We cannot hear anything, if we are running on diesels (incl. snorkeling), it's just too loud. On electric engines, silent running doesn't interfere much with the hydrophone's effectiveness, but moving at flank speed shrinks the detection range to just a few hundred meters.

So: It'd be great, if you could help me mod the UBoot_Sensors.sim. The goal is to have the above simple hydrophone sensors, but keep other changes/fixes, that are applied by REM, IRAI etc.

Okay, for a start I will elaborate and submit to you a chart resuming the main hydrophone detection factors, and how they affected different listening devices. In the meanwhile, I suggest you to have a close look into the following document, drafted by the developpers of "Danger from the Deep":

Sonar reference and implementation details

[gap]

I have created an on-line chart resuming all the information we have gathered so far:

https://docs.google.com/spreadsheet/...lE&usp=sharing

I have left the document open for editing by anyone: feel free to correct any mistake I might have made, or to add information in case you find any new source.

You will notice that there are several discrepancies between different sources, especially regarding maximum ranges, maximum allowed speeds during hydrophone listening, and deaf angles. Talking about the latter, there seem to be some confusion between totally deaf arcs, and arcs at which sound detection would have been harder and/or lesser accurate but still possible, for KDB and Balkon apparatus. This might partly depend on the fact that "astern handicaps" could have varied greatly, depending on the propulsion adopted during underwater listening. The above statement is especially true if referred to the KDB which should have provided correct bearings at any angle, provided that U-boat propulsion was switched off during its use.

I will let you to draw the conclusions; at this moment I have just a few general suggestions:

• Wave, speed and noise factors are global settings, and it is likely that in stock game they are applied indiscriminately to all the hydrophones. I don't know if the addition of individual factor modifiers for each hydrophone would be possible via scripting, but this would be a nice (and needed) addition.
  
  
• I like the depth/range curve shown in your last post. Yet, I think you should implement a steeper function (or a constant offset) accounting for the drastic reduction of wave noise in the first meters of water, and subsequent enhancement of listening range at relatively shallow depths. This is especially important if you decide to adopt 80m bsl as best listening depth, and a maximum single contact detection range of only 20 km, as per our sources. To this purpose, you should keep in mind that a difference in height of just 2.5 meters, betweeng the GHG and the Balkon, made a big difference, contributing to make the latter fairly effective even on surface. You should also remember that the min sensor depth property set in SensorData, is relative to height of sensor linking bones in world coordinates, whereas U-boat's depth reported in game is relative to her draft (i.e. the height of the lowest part of her keel). For each U-boat model two sensor linking bones are used: one for GHG and Balkon Gerat, and one for the KDB. If needed, I can provide you with their heights in SH5 world coordinates.
  
  
• Our sources show a consistent difference in detection ranges and sound emission spectra (which, on turn, affected bearing detection accuracy), between surface vessels cruising at different speeds/engine rpm's. In game, the RPMDetLevel property (one for each hydrophone, is SensorData), bonds ship rpm (as a percent of their maximum rpm) with the probability of detection by the hydrophone operator. This is essentially wrong, because it makes a tugboat hanging around at 5 knots potentially more detectable than a destroyer cruising at 15 knots. Absolute rpm levels should be used instead. Ideally, a propeller rotating at an higher speed should:
  • have an higher chance of being detected by the AI operator, and have a louder sound for the human player;
  • be detectable from further away, both for AI crew and player;
  • allow a more accurate bearing detection, both for AI crew and player.
  
  
• All our sources agree on the fact that convoys were detectable from a range at least two times longer than single contacts. This is yet another important aspect obviously not modelled in game. You (or our common friend, Mr. Know-It-All ) may have an idea on how to fix it via script. If not, I thought of a possible workaround which might partly fix the problem for the AI operator, but not for the human player; in SensorData, there are two parameters affecting detection probability: ProbInsideArc (i.e. the detection probability, in percent) and SweepArc (i.e. the arc, in degrees, within which ProbInsideArc is defined). By reducing SweepArc and ProbInsideArc, the detection probability for single contacts (covering just one arc, esp. at long range) would be reduced, but it would be relatively higher for convoys, as they would cover more than one arc, and independant arc probabilities would be combined. Does it make sense to you?

[vdr1981]

I must express my gratitude one more time, this mod is such a large improvement !

I've got few questions though...

Is there any way to prevent this?

It can be very annoying when large conwoy is in site...

Also it would be really awesome if you could make some changes for sonar too...Current implementation isn't so realistic at all...

[Mikemike47]

Originally Posted by vdr1981

I must express my gratitude one more time, this mod is such a large improvement !

Agreed.

Will there be an English version for the sound files someday?

[vdr1981]

Bump! Tscharlii, please don't give up on this mod, it has so much potential...

[gap]

Originally Posted by vdr1981

Bump! Tscharlii, please don't give up on this mod, it has so much potential...

undersigned

[BobbyAmok]

hello masters of mod!

and special greetings to tscharlii for this great modification (the sonarguy is now
my best friend below deck, i call him charlie. )


^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^
is there a posibility that the messages of the sonarguy called out by heard contacts (in german: horchkontakt) that are shown in the message-box can be changed to the german terms?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^


i'm german and i like to play the game in german language. i modificated the ui mod of the dark wraith to german by changing the menu.txt file (easy one ). so every call in the message-box is in german, except messages indicating the direction of a contact. it's not a big deal, but it bothers me more than it should.
if there is any advice how it could changed would be very welcome!

wohl auf!

"Die Südfrüchte runter vom Kartentisch. Auf Bananen kann ich nicht navigieren."