Discussions concerning the Uboat Commander's Handbook

[Paul Riley]

I thought it may be worthwhile starting a new post concerning the Uboat Commander's Handbook.This could involve discussions on tactics in general,and also with certain errors to be found in the document,which would no doubt cause some level of confusion for the reader.
I ordered the book 4 days ago and am awaiting its arrival from the US,but in the meantime I am reading an online version of the book,and have come across the first error (or at least I assume it is) in the document.It is concerning ASDIC and sound location in general.Below is the exact reference -

198.) During the night surface attack, the submarine can:
I. be sighted,
II. be sound-located,
III. be located by ASDIC.
I. Danger of Being Sighted.

I am concerned about lines II and III.On the surface a UBoat should be unaffected by ASDIC and or hydrophone detection in general,or this is the most common assumption by a lot of people.
I am thinking that it may have been a preliminary expectation of ASDIC in the very early stages of the war,when the Germans had little knowledge or experience of allied sound capabilities.
Or is it simply an error in the text?

Thanks.

[onelifecrisis]

Just a guess... perhaps sound-located means simply "heard" by the Mk1 Earhole? Hitman told me that there are accounts of German sub crews getting so close to their night-time prey that they could hear the conversations on deck.

But, the ASDIC one is weird. :hmmm:

[Kubryk]

I'm a newbie, but I'd say that 'be sound-located' could mean 'heard by a human ear'.

[Hitman]

The surface of the sea is a source of a lot of noise, and there are many good reasons for that: Waves splash, wind howls, and external noises that race through the air hit it, switching to an environment of much higher density (water) where they are slowed down but not completely stopped (making the most of the noise in the first metres until they fade away).

Therefore, locating a ship that sails on the surface with hydrophones is more difficult BUT not impossible at all. In fact, a noisy diesel engine like the one on the U-Boats and his fast turning, small, double screws can probably be heard well at a reasonable distance if going quick enough. The commander must know this and minimize the risk by making slower speeds and taking other precautions. That's what the manual pretends to say IMO.

FYI, the german cruisers also shipped hydrophones, and IIRC during the Battle of Danemark Straits the Prinz Eugen located the Hood and POW by sound before they were in sight.

About the ASDIC you can more or less say the same, and add to that the normal beam geometry of it (It is located under the bow of the destroyer) will prevent the echo from bouncing well on a surfaced U-boat (And to a certain extent, also from a submerged one). But the risk still exists in certain conditions.

Of course the diesel can be heard by the human ear, and that risk also exists even if minimized if the listener is not in a quite place (And a surface ship hardly is one).

In any case, it should be worth adding that the book forgot another mean of knowing a U-Boat is around, which could sometimes give it aways (It certainly DOES with normal surface ships, I can testify that having sailed myself): The smell of the diesel in the air.

And a final note: Take the mentions to enemy technic in the UKH with a grain of salt. When it was written it just reflected assumptions on the capabilities of enemy equipment based on assumptions and experience, not on reliable data like we have nowadays. For example, in 1942 BdU didn't even know that the allies had developed a radar small enough to be fitted in aircrafts, and in 1943-44 it was some steps behind the allied development about the wave amplitude in which that aircraft mounted radar operated.

[Paul Riley]

Having re-read the article more I can see now that the sound detection does in fact mean the sounds emitted by the screws running at high speed,typically on calm seas,where the noise would be harder to mask,more so at extremely close range.Therefore a drop in speed would be needed.
Having said that,firing at minimum ranges when allied detection methods was constantly improving would be nothing short of suicidal,forcing the UBoats to attack at ever increasing ranges.Especially so against large well defended convoys.
Interesting about the smell of diesel,again,a sure give away.Not much of a problem in SHIII though,unless there is even a mod for that!

:yep:

[Paul Riley]

"heard" by the Mk1 Earhole? :hmmm:

Mk1 earhole,I like that :har:

[Sailor Steve]

This topic is verboten. The U-Boat Commander's Handbook is not to be discussed, and never questioned. You will obey orders and do as you're told.

I was never here, and you didn't hear this from me. I will self-destruct in five seconds.








Now that that's out of the way...

Since it specifically refered to the night surface attack, I think that was meant to be more of a warning than taken as fact; in other words "Never assume that you can't be heard or detected".

[Platapus]

And a final note: Take the mentions to enemy technic in the UKH with a grain of salt. When it was written it just reflected assumptions on the capabilities of enemy equipment based on assumptions and experience, not on reliable data like we have nowadays.

:yeah:

It was a manual for training officers, not a scientific thesis.

[klh]

Below is the exact reference -

198.) During the night surface attack, the submarine can:
I. be sighted,
II. be sound-located,
III. be located by ASDIC.
I. Danger of Being Sighted.


The original German of the section in question is...

198. Das U-Boot kann beim Uberwassernachtangriff:

I. Gesehen werden,
II. Gehorcht werden,
III. Geortet werden.

My rough translation would be...

198. During a night surface attack, the U-boat may
I. be seen
II. be listened to (heard)
III. be direction-located

(any native German speakers feel free to correct me) :06:

While III. could mean ASDIC, I'm thinking it more likely refers to radar. By the way, the section "I. Danger of Being Sighted" starts a new section to further explain this hazard.

[Platapus]

klh,

Excellent point!!!

One has to consider errors in translation when discussing this issue.

[klh]

Thinking about this a little more, I've got another possibility.

When this edition of the handbook was written (1943), Allied radar technology wasn't well understood by the Germans. Sections 214-216 speak of a direction-finding technology that may be used on the surface, but it's not clearly explained. It may be that the Germans thought it could be an advanced form of ASDIC. The handbook almost seems to be downplaying the danger, and encouraging the commander to stick with the attack. The translators called this ASDIC, perhaps because even they were unaware of radar technology. In either case, it seems that the Kriegsmarine was aware that the Allies were using a technology that was useful for detection and direction finding on the surface.

[Deamon]

I ordered the book 4 days ago and am awaiting its arrival from the US,but in the meantime I am reading an online version of the book,and have come across the first error (or at least I assume it is) in the document.
Errors ? I think in the first place we should talk about translation errors and not good translations instead.

It is concerning ASDIC and sound location in general.Below is the exact reference -

198.) During the night surface attack, the submarine can:
I. be sighted,
II. be sound-located,
III. be located by ASDIC.
I. Danger of Being Sighted.

I am concerned about lines II and III.I don't find this translation very good. In german it says:

II. gehorcht werden

"gehorcht" and "horchen" in general always reffers to hydrophones. "gehört" and "hören" would reffer to heared by ears.

so perhaps they should have translated II as:

II. hydrophone detected

On the surface a UBoat should be unaffected by ASDIC and or hydrophone detection in general,or this is the most common assumption by a lot of people.This must be a wrong assumption cause when we are talking here about an u-boat going close to a convoy it may get very well within the cone of an asdic at close distance.

I think it is commonly said that the asdic was in a fixed slight downward angle installed, to avoid surface echos, but the later asdics could change the angle at will, afaik.

I don't know now how steap the downward angle of the upper boundery of the asdic azimuth is but it should be fairly flat since u-boats at periscope depth are supposed to be detected at all ranges so on the surface, u-boats are deep draught vehicles, when you are close enough and that's what you are when you attack a convoy, you may get very well in the detection cone of the asdic. And besides that you can find all the answeres in III.II and III.III, if you care to read it a bit further.

[Kapt Z]

Now that that's out of the way...

Since it specifically refered to the night surface attack, I think that was meant to be more of a warning than taken as fact; in other words "Never assume that you can't be heard or detected".

Good point. I read it a few years ago and do remember it stressing the opposite as well, "Never assume that you HAVE been detected".

[Hitman]

"gehorcht" and "horchen" in general always reffers to hydrophones. "gehört" and "hören" would reffer to heared by ears.


Was about to point that out myself, now that I saw the german original :up: