Immersive techniques for the true subsimmer!

[John Pancoast]

Originally Posted by Drakken

I took a short hiatus from my new TWOS campaign, so I'm still at September 2nd, 1939 in Polish Waters.

Using Real Navigation, with my written KTB:

- I use supermarks to plot a patrol waypoint on the map.
- Each time I plot a new course to a waypoint, I calculate an ETA and set my alarm to the estimated clock time.
- My Navigator does regular Dead Reckoning readings, and I use them to correct both my course and my ETA.
- When the alarm rings, I slow down to ahead one-third and order my Navigator to make a Celestial Navigation reading.
- When the Navigator is done, I dive to 20-30 meters to initiate the hydrophone scan protocol.

I know their is an automated routine for patrol grids, but in the Polish waters I prefer to keep control. Feel free though to improve my routine, though.

Fwiw, I've never been able to find any proof that actual commanders did a hydro scan protocol on a routine basis. Lot of water out there; needle in a haystack
Maybe someone else has ?
I.e., Kretschmer did a daily routine early morning dive but that was to give the watch crews a break from that taxing job vs. for a hydrophone check.
Of course a check can be a side benefit of such a routine too.

[Drakken]

Originally Posted by John Pancoast

Fwiw, I've never been able to find any proof that actual commanders did a hydro scan protocol on a routine basis. Lot of water out there; needle in a haystack
Maybe someone else has ?
I.e., Kretschmer did a daily routine early morning dive but that was to give the watch crews a break from that taxing job vs. for a hydrophone check.
Of course a check can be a side benefit of such a routine too.

That's interesting. I was wondering if Kaluens were really doing hydrophone checks every few hours because, on the face of it, doing so would absolutely kill their efficiency: Imagine basically stopping every two-four hours, lose time diving and surfacing, all for a 15-30 minutes spent on the hydrophone...

It makes sense when you are submerged during the day, or when weather is suboptimal, but else all those stop-and-goes would be a risk their electric engines, wouldn't they?

[John Pancoast]

Originally Posted by Drakken

That's interesting. I was wondering if Kaluens were really doing hydrophone checks every few hours because, on the face of it, doing so would absolutely kill their efficiency: Imagine basically stopping every two-four hours, lose time diving and surfacing, all for a 15-30 minutes spent on the hydrophone...

It makes sense when you are submerged during the day, or when weather is suboptimal, but else all those stop-and-goes would be a risk their electric engines, wouldn't they?

I don't know if doing such in real life would have had any affects on the mechanical/electrical side of things.
But I have a hard time believing any u-boat did such (if at all) at the frequency some players do. Some players also listen to the phones themselves which of course wasn't a commander's routine but everyone is free to play the game as they see fit.

[derstosstrupp]

Kretschmer’s policy was to dive for two hours before dawn. Merten had a similar practice. In general though, I have not come across any dives for the express purpose of doing a hydrophone check unless it was foggy or the weather was very poor. Daily trim dive an absolute must, which would’ve been used to service the torpedoes as well, but never simply a hydrophone check. What games just don’t get correct is how poor the acoustics of some sea areas are. Hirschfeld’s book (former radio mate, can’t remember the name of it) sheds a lot of light on how unreliable hydrophones were. Plus mast tips could be spotted out to 30 km or so in some cases, smoke even further. Hydrophones are overpowered in nearly every U-boat sim it seems.

[John Pancoast]

Originally Posted by derstosstrupp

Kretschmer’s policy was to dive for two hours before dawn. Merten had a similar practice. In general though, I have not come across any dives for the express purpose of doing a hydrophone check unless it was foggy or the weather was very poor. Daily trim dive an absolute must, which would’ve been used to service the torpedoes as well, but never simply a hydrophone check. What games just don’t get correct is how poor the acoustics of some sea areas are. Hirschfeld’s book (former radio mate, can’t remember the name of it) sheds a lot of light on how unreliable hydrophones were. Plus mast tips could be spotted out to 30 km or so in some cases, smoke even further. Hydrophones are overpowered in nearly every U-boat sim it seems.

[Angelis]

I‘d say during a normal patrol on search for "Fette Beute" Rundhorchen was a common thing due to it's effectivness. You could detect convoys up to 100 km away.

http://www.uboataces.com/hydrophones.shtml

[John Pancoast]

Originally Posted by Angelis

I‘d say during a normal patrol on search for "Fette Beute" Rundhorchen was a common thing due to it's effectivness. You could detect convoys up to 100 km away.

http://www.uboataces.com/hydrophones.shtml

Even if true, that was only under the rare optimal conditions and as pointed out such occasions were the exception.
If you have definitive proof that actual commanders did such a procedure on a routine basis that would be a great help, thanks !

[Angelis]

Originally Posted by John Pancoast

Even if true, that was only under the rare optimal conditions and as pointed out such occasions were the exception.
If you have definitive proof that actual commanders did such a procedure on a routine basis that would be a great help, thanks !

Not right out of the box but I‘ve read a contempory witness report of a U-466 crewmember.
Unfotunately on German.

Saying:
"Am 26.1. 1943, 17.14 Uhr Alarmtauchen wegen eines in Sicht gekommenen Flugzeuges. Um 20.38 Uhr hatten wir die erste Horchpeilung von einem Geleitzug und operierten auf diesen, jedoch ohne Erfolg, weil wir einen Maschinenschaden im Dieselraum hatten, die Kupplung war unklar."

English:
"On 26.1. 1943, 17.14 o'clock alarm diving because of an airplane coming into sight. At 8:38 p.m. we had the first sounding of a convoy and operated on it, but without success, because we had engine damage in the diesel room, the clutch was unclear."

https://ewnor.de/wk/769_wk.php

[John Pancoast]

Originally Posted by Angelis

Not right out of the box but I‘ve read a contempory witness report of a U-466 crewmember.
Unfotunately on German.

Saying:
"Am 26.1. 1943, 17.14 Uhr Alarmtauchen wegen eines in Sicht gekommenen Flugzeuges. Um 20.38 Uhr hatten wir die erste Horchpeilung von einem Geleitzug und operierten auf diesen, jedoch ohne Erfolg, weil wir einen Maschinenschaden im Dieselraum hatten, die Kupplung war unklar."

English:
"On 26.1. 1943, 17.14 o'clock alarm diving because of an airplane coming into sight. At 8:38 p.m. we had the first sounding of a convoy and operated on it, but without success, because we had engine damage in the diesel room, the clutch was unclear."

https://ewnor.de/wk/769_wk.php

Thanks. Assuming the time frame between the times mentioned was three hours and 24 minutes, it sounds like they just happened to pick up a convoy because of their aircraft avoidance dive vs. the dive was part of a daily routine of hydrophone checks ?

[Angelis]

Not sure.

Why should a commander not use all the resources at his disposal to carry out his orders? Whether or not in routine procedures is a matter of the respective operating concept, I guess.

[derstosstrupp]

Originally Posted by Angelis

I‘d say during a normal patrol on search for "Fette Beute" Rundhorchen was a common thing due to it's effectivness. You could detect convoys up to 100 km away.

http://www.uboataces.com/hydrophones.shtml

I’m sure. The KTBs, doctrine, and contemporary literature I’ve read (and that’s quite a bit) strongly suggests no. Uboataces.com is also generally not a good source and has quite a bit of errors. As I said, there were acoustic nuances in different sea areas, I would suggest you read Hirschfeld’s book. There’s a good reason why the Handbook for U-boat Commanders explicitly states that the only time the hydrophone should be used is in cases of dire necessity if the submarine is forced to be underwater for one reason or another. Are you familiar with that document?

https://drive.google.com/file/d/1u_W...w?usp=drivesdk

Assertions like “why wouldn’t they use all the resources at their disposal” generally result in ignoring nuances of reality and misunderstandings. And the answer as to why they wouldn’t have used that resource, as I said, was that the eyeball was more reliable on a clear day.

The number one source of course is the KTBs, what they actually did. I suggest you also read through those.

A selection here:
http://uboatarchive.net/KTBList.htm

[John Pancoast]

Originally Posted by Angelis

Not sure.

Why should a commander not use all the resources at his disposal to carry out his orders? Whether or not in routine procedures is a matter of the respective operating concept, I guess.

Well if said resources don't reliably do a good job, no sense using them. Let alone the vast distances of the water being operated in vs. the range of the phones.
I'm also curious about the uboataces.com article; on one hand it says the phones couldn't pick up range, on the other it says they could pick up a convoy at 100km.
So how did this 100km figure come to be determined, i.e. ?

[Drakken]

Originally Posted by John Pancoast

Even if true, that was only under the rare optimal conditions and as pointed out such occasions were the exception.
If you have definitive proof that actual commanders did such a procedure on a routine basis that would be a great help, thanks !

So, realistically, hydrophone sound checks should be limited to very calm seas and ocean waters? I recall reading the Handbuch that salt level in the Baltic and North seas made it harder for sound to travel underwater.

[derstosstrupp]

Originally Posted by Drakken

So, realistically, hydrophone sound checks should be limited to very calm seas and ocean waters? I recall reading the Handbuch that salt level in the Baltic and North seas made it harder for sound to travel underwater.

It should be limited to bad visibility conditions, fog. I do a “trim dive “at 0600 every day, so that’s also a time.

[John Pancoast]

Originally Posted by Drakken

So, realistically, hydrophone sound checks should be limited to very calm seas and ocean waters? I recall reading the Handbuch that salt level in the Baltic and North seas made it harder for sound to travel underwater.

See derstosstrup's reply I want to repeat though at least from my point of view; if doing routine phone checks, realistic or not, makes the game enjoyable to someone, great ! Nothing wrong with that at all.


Heck, I prefer 8k environments to avoid the night vision problem with 16k and above ones, and use a set of escort ai files that most people would rightly call unrealistic in terms of escort equipment setup but if gives much more "realistic" gameplay (imo).

Gameplay is what its all about for me; i.e. I'm not a fan of sticking historical equipment capabilities numbers in games for various reasons one of which is more often than not they won't work in a game's limitations.
I.e., I also never considered the depth charge blast damage range or the pinpoint drops a problem in the game (still don't ). Realistic ? Maybe not numbers wise, but perhaps they are that way to help the brain dead escort ai. I consider both "problems" actually providing better gameplay with than without.