@Matta

I have the same Problem like Michael J.Caboose

Seems like my hydrophone Operator recognizes Contacts just when they can be heard in the middle range of the Hydrophone.

And i want to say thank you to your work!

@J0hn Shadow, unfortunately 148x speed is definitely beyond the point that the game's automation starts behaving funky. The default hydrophone settings are just forgiving enough for you to not notice. Unfortunately there is nothing a mod can do about that,

@Lopot4813 and @Michael, the values in the screenshot are as expected. The 'direct detection range' refers to the range at which you get all of the ship information from just the hydrophone. Single ships in this game are actually a 'group' of one ship-- as such they will be detected at ~50% of the 'group detection range' (as the total noise of the 'group' is not enough to be detected at the maximum group detection range). As for the manual audio being high, I'll do some testing soon. Is there any more information you can share in the meantime?

When i scroll over the Hydrophone it gives me the ranges, and it shows that the group detection range is 35km while the single ship detection range is just 1.8km
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3497318991

I'm having the exact same problem as Michael, I can hear the hydrophone contacts very clearly, but the AI never seems to register them until they are extremely close. And I always use 48x time compression when listening with AI.

Hydrophone station bugged after update, cant leave and background audio of the sea gone. Not sure if it is this mod or sounds of war mod that is conflicting with update

I'm playing the game only at 148x speed and I almost always encounter the same problem. I never trust my hydrophone guy. Even if I hear it clearly, even in the middle frequencies, the guy just sits there and is looking at the dials as if he doesn't remember what his job actually is - much like the guy sitting beside him^^. I'd love to have a more limited hydrophone, but that's a bit off - i think ^^

I'm not sure it's a probabilistic mechanism. I do know that time compression janks the whole process quite a lot though. Is this something you have witnessed at low time compression levels? I have done quite a bit of testing at low time compression and never experienced this.

What Drexack said is exactly what I mean, it seems the way the game works the range of the hydrophone is not the only thing at play when you leave the station to an ai officer.

I think what Michael refers to, in more technical terms, is increasing the probability of the technician to pick up the contact, since they are often well in range (<5 km) before he does so. Something seems to prevent the AI from picking up signatures, manual listening is not affected though.

In other terms: manual listening works fine, but the technician needs to become more reliable at picking up contacts.

This is not necessarily something the mod introduces, though. With the ~120 km range of vanilla, it often happens that single freighters are picked up "only" within 40 km. Not a problem, but when the maximal range is 16 km, this reduces to ~5 km.

Hey Michael, what do you mean exactly with "ships will be in range"? The blue range-circle represents the maximum possible detection distance. Only big convoys will be picked up at that distance.

I think it might be a good idea to increase the ranges so your officer will actually pick up sound contacts. It seems to me a lot of the time ships will be in range but the hydrophone opererator will never pick them up.

Thank you very much!

[2]
A group of ships will only be detected AT the maximum range, if it has a very high 'Group Detectability' value. This group value increases logarithmically with the detectability of each of the groups' ships.

So basically, the game sums up the detectability of each of the groups ships, then takes the log (with base 'Group Hydrophone Detectability Log Base') and scales the result by the 'Group Hydrophone Detectability Scale'.

So for my values:
Group detectability = 0.365 * log_3.15(sum of ships detectability)

Those two parameters thus determine at what % of the GroupHydrophoneRange e.g. a single ship will be detected.

Then finally the 'Out Of Range Observation Validity Duration' simply influences for how long after an observed ship is out of range it remains observed.

[1]
Hey @Special Guest Star-- I recently responded to someone on discord with an explanation. I'll copy it here:

The game does hydrophone detectability in the following way.
Every ship is part of a 'group' of ships, this can be a group of 1 if it is a lone ship, or more if it is a convoy. The 'GroupHydrophoneRange' is the maximum distance in km that a group of ships will be picked up (the blue circle). The 'HydrophoneRange' distance is-- I believe-- the distance in meters that a ship will be 'fully identified' by the hydrophone, so even while underwater you can see the name in the tooltip and stuff. The 'SurfaceRangeModifier' value of e.g. '-0.91' will reduce the ranges by 91% while the uboat is on the surface.

Hey I'm trying to mess with the hydrophone ranges, and I found this mod changes a few strings in the settings. Could some one please explain what the following strings (and their values) exactly do?

Out Of Range Observation Validity Duration
Group Hydrophone Detectability Log Base
Group Hydrophone Detectability Scale
GroupHydrophoneRange = 35
HydrophoneRange = 2816

Thx in advance.

@Drexack - Thanks for the proper guidance! I think "Case1" is easier to draw in game, but drawing on paper with right angle ruler "Case2" is easier.

Thanks for the extra advice and my apologies for disturbing the comments section. I will try all of the suggested methods and pack even more food

As much as I appreciate the nod to Das Book, do yourself a favor and take advantage of the Kreuzeraufgabe [drive.google.com] for intercepting contacts instead of using the distance-time table. It'll give you the exact intercept course.

@Vangheist - Enhanced BdU report marks a coordination on your map with time, speed and direction info of enemy ship. You can draw a route line based on this info. As you mark a travel destination on this route, CourseLine+ shows at your current speed how much time it takes to get there from your current position. Das Book's time table helps to calculate where enemy ship will be on given time. With this two info you can calculate an estimated meeting point, where you and enemy ship should be there on a given time. If you get there and no smokes seen on horizon, then use your hydrophone guy to get a proper direction. Realistic Hydrophone mod's reduced (~20km) detection range should be enough in this way.

@Vangheist - My opinion is same as yours on that, using only this mod makes game so hard (realistic) and most of your game time is just about searching enemy ships on supposed travel routes. I can recommend you some more mods, which helped for me.
1) Enhanced BdU Convoys Reports - you get more reports exactly where and when enemy ships has just been seen (more reports = less searching)
2) CourseLine+ - helps you calculate your current speed, it shows when will you get to your destination (where to catch enemy ship on it's route)
3) Das Book - it's "speed-distance-hours" time table helps to calculate how much distance a ship travels at reported speed

@Vangheist
That's kind of to be expected.
IRL, U-boats would often have patrolled in groups, which maximised the probability of encountering a target. Once contact was established, it was communicated via radio and the group attacked as a Wolfpack.

That's not really a thing in the game. You're on your own, hence you're going to miss a lot of targets.
But there are radio contacts you sporadically are informed by friendly U-boats. These will most likely be the majority of your targets with this mod.
I consider this to be intentional.

Now, expect to be at sea for 3-5 weeks before expending all your torpedos. And even that is not quite true to life, some U-boats spent weeks at sea and sank only 1-2 freighters. I have been on patrols that went on for 30+ days without a single contact.

So if you're not into that slow paced, methodical kind of play style, this mod might indeed be not for you. Realism should not get in the way of fun .

Nobody's forcing this mod on you, Vangheist. You can choose to not use it.

I don't mean to be negative because I think that the vanilla hydrophone is far too effective, but actually how do you deal with losing that advantage the way this game is set up? I have terrible luck trying to find anything by visual contact alone in most patrol grids on open sea, even when following known shipping routes.

I really do want to learn and adapt, but I'm having a very hard and uninteresting time. Perhaps this experience just isn't for me?

When I enter listening after viewing map, there is a very loud interence. When I just zoom out to 3rd person then again back to listening it fixes. Not sure if ots related to the mod, but started happening after mod update. Its an anoying feature every time.

Awesome, thank you for this update!
It does explain my experience with the radio officer being very bad at hearing contacts. As for the manual listening range: I feel like it's not affected in the same way by the weather. I've been hearing contacts just fine.

I have updated the mod today.
After some testing, it seems that the mod itself was not broken by any of the recent updates.

2025.1 patch 8 added:
- Rough weather now negatively affects passive hydrophones and active sonars. This effect can be inspected in the tooltip of the detection notification.

This seems to also apply to the uboat's own hydrophone. This means that there is a ~10% decrease in range during slightly windy weather, ~30% during rain and ~75% decrease during storms! In order to compensate for this new functionality, I increased the ranges in the current mod by ~10%. Hydrophone performance will thus be slightly improved over previous levels during completely calm weather, but still hampered when it rains/under high winds.

The manual listening is unchanged. I am unsure whether the new functionality added in patch 8 also affects the manual audio-- if not, I might see if I can reduce it by the same percentages.

I can hear ships manually, but my radio man is deaf, unable to detect anything (eg. single ship 3-4 km away). Please update.

update pls

Please update

Doesn't seem to work anymore, I can hear contacts no problem, but my radio man/hydrophone operator refuses to detect it, even though it is very close and very loud on the hydrophone.

This mod adds just the needed last slice of realism. Hard to find ships like it should be!

works with 2025.1. Love it and I recommend it for realism fans. Vanilla hydrophone is way too overpowered which allows to find ships too easy resulting in too much success. With the mod its a much greater challenge finding contacts, be aware.
BTW. it does not require restarting the career. Just tested activating it in running campaign and it worked. You can enable/disable this any time.

Thanks for your mod. I tested UBOAT today - When hydrophone is in short range mode and enemy transport ship is below 1km range, I can just hear it. Shouldn't it be easier to hear it at this distance? With the middle setting, on the other hand, the opponent can be heard very loudly

@Matta - Question : Is it possible to remove the hand-wheel noise when the player turns it? Given the excellence of German engineering at that time, I'm sure the wheel-handle was mounted on ball-bearing and well greased ! And thanks again for this mod, really appreciated !

I've been using the mod for several hundred hours. What to say?

It's realistic: "German submariners, with good hydrology, detected a single transport in noise direction finding mode at a distance of up to 100 kb , and already from a distance of 20 kb they could obtain a range to it in the “Echo” mode."

And this is very good thing.

But hydrophone operators can't hear obvious noises - and that's not a good thing. A sonar specialist with his absolute music hearing should be able to hear better than the captain.

If this could be tweaked a bit it would be great, don't take it as an edification. Best regards, and very grateful for your work.

Hey Matta,

I've noticed that, while the manual listening works as intended, especially in less ideal weather scenarios, my hydrophone operator will not pick up any contact unless its closer than 4km (that particular example was at 9kn wind, going speed 2 at periscope depth). Even at with just a light breeze their detection range drops to 8-10km. Manual listening doesn't seem to be affected to that extend.
To me these distances seems absurdly close. Someone on the Discord claimed that's to be expected, and the 16-19 km you cite is only in the case of perfectly still seas, at 50m depth, with the engines being off. Is that so? Am I being gaslit? Is it just me who finds that odd?

In any case, love the mod and wouldn't want to play without it!

Cheers

Hi Matta,

First, thanks for creating this mod.

I feel like I'm not quite ready for the full challenge of a very realistic hydrophone range, so thinking of changing the xlsx values to somewhere in between your values and the native ones.

I'm guessing I'll also have to change the script values to adjust manual listing range. Could you please let me know what the default values are? Or what values I should put in the script file for about 50% of native/default?

I asked some Uboat enthusiasts to confirm my learnings and found out: the 30-40km mark is a fair value. So, well done! And i also learned, that ship at 5-10km range left sound bearings all around the uboat. So, when the operator turned it, you could hear the ship at every angle, only at the correct bearing where the ship actually was, the noise was sharper. Thats something totally new to me and shows, how hard it was to identify the correct bearing of a contact.

Interesting mod! From the books i read i learned, that an experienced hydrophone operator could hear convoys up to 100km away. But only if the conditions where good. Some sources in the internet confirm this. So, i think 32km maybe is a bit too low. Personally i would make it 50km.

@Ethan it's hard to discern whether this mod is causing problems with manual listening because the vanilla system is quite finnicky itself. Can you share some more details about what you found?

i take it back, for some reason ill only hear contacts in range when using the command to see them on the map otherwise it doesnt work properly

theres so many comments saying this mod isnt working so i did a tiny bit of testing on my own and it seems like the mod is working properly

I tried incorporating this into my running career using the "Datasheets reload - fixed" mod from the workshop.

For the AI doing the spotting, it seems to work just fine. Although I feel like it's a little underpowered, as my officer picks up a hydrophone contact long after I can see their funnel smoke on the horizon. If I were to rely only on my officers, I think I would return empty handed from patrols more often than not.

Anyways, I think it didn't work for the manual listening. I'm still picking up propeller noises from what feels like 60km away. Just something to keep in mind.

Using latest patch and a real flag mod as well realistic hydrophones mod, I found no contacts for weeks, so I changed back to vanilla to see what gives. There, on reopening the game, I found a single ship within the 20km range which did not show up with the mod enabled.

No, it was around 270. I think it's a bug, and probably not yours. I just got two contacts on hydrophone, seen them with periscope, and they got immediately identified and removed from hidrophone list. Infobox marked them as visual only. Then I waited a little bit, and they disappeared from visual, and become propeller noises.

Not sure what is the cause, maybe no spoilers mod, or hardcore aiming settings. Anyway it's not related to hydrophone.

@Thoth was there no separate propellor detection? Could the target have been directly in front/behind the boat?

@Matta, No compression. I was waiting for the ship to approach, went underwater. And ship got detected only when it entered the direct detection zone. Propellers was clearly herded in hydrophone, but sonar man ignored them even in manual mode.

Can it be because I was actively observing the ship with periscope? But again, the infobox of the ship was saying that it was detected only visually and not by hydrophone.

Maybe it's a bug , don't know.

@Thoth were you in time compression? the 'direct detection' distance is (according to my understanding) the distance at which ships show up on the 'Ship Notification' (the blue icon with a ship). The 'group detection' distance is the distance at which ships show up on the 'Propellor Notification'. Single ships are also treated as a 'group' in the game.

@marLeo nope, but their hydrophones are also not scaled to unrealistically high levels in vanilla ;)