Bugs and Howlers that have to be fixed before release

[Navarre]

Originally Posted by Antar

Tomi_099 has unlimited hour budget and unlimited deadline... and it is a reason why his work is so perfect.

And he can use millions of polygones to detail his reference models.
A 3D designer who created the content for a particular game is limited in the number of polygons used by the game engine.

[Sailor Steve]

Jim, did you fall asleep on the 'Submit Reply' button again?

[Jimbuna]

Originally Posted by Sailor Steve

Jim, did you fall asleep on the 'Submit Reply' button again?

Didn't you know...I've taken up tap dancing again

The truth is I've three 1/700 kits here but my paint and tools supplier is awaiting stock deliveries

[Catfish]

Hello,

just ran about some bugs in SH3 and 4:

1. Lights shining through things

2. Destroyers hearing U-boats through land masses, and then going directly at them beaching their ships

3. Destroyers detecting U-boats running silent at Periscope depth by sonar - THIS IS WRONG
(the sonar used would not actively detect subs at pd even in 1945, or only if the sub is 10 meters in front of the bow. The waves within the sonar cone do not travel parallel to the water surface ! ! Gawd, read some books and don't listen to propaganda lol)

4. Realistic diving depths down to and below 220 meters without flickering lights and automatically increasing damage

5. When batteries in german U-boats were loaded, BOTH propellors would still turn, since the dynamoes were just clutched to the spinning shafts - resulting in a slightly reduced top speed but both props turning.
Maybe give the user more control - it was certainly possible to stop one shaft completely, and charge the batteries with the resp. Diesel, if seldomly done.
The type IXD had some special silent running electric engines with belt drive, along with special smaller Diesels (that were not the boat's main propulsion Diesels) for charging the batteries at minimum Diesel spent.

6. Please model the electronic warfare gizzmoes right - detecting device with the right detection antenna or different really-used combinations, that is.
- In that context: Pleas make all active radar ("Funkmess") devices being able to turn off against detection, and also model it that is really not be found by radio emission if turned off



Posted by Sailor Steve:

Quote:
Originally Posted by Catfish
3. Destroyers detecting U-boats running silent at Periscope depth by sonar - THIS IS WRONG
(the sonar used would not actively detect subs at pd even in 1945, or only if the sub is 10 meters in front of the bow. The waves within the sonar cone do not travel parallel to the water surface ! ! Gawd, read some books and don't listen to propaganda lol)

So it is your contention that the best possibility of escape for a submarine was to stay at periscope depth and run silent? Do you have any evidence for this ever being tried and working? Why then the common advice "run silent, run deep"?

Active sonar may or may not sense submarines at periscope depth, but active sonar does not depend on how much noise the submarine is making. Can hydrophones not detect a submarine at a depth of 45-65 feet?

You say "read some books". Which ones? Specific quotes, please.

Also, why a new thread for this and not a post in the existing 'Bugs and Howlers' thread?
__________________
"I've a little wet home in a trench, where the rainstorms continually drench. There's a dead cow nearby, her feet aimed at the sky; and she gives off a terrible stench.

Underneath, in the place of a floor, there's a mass of wet mud and some straw. But with shells dropping there, there's no place to compare with my little wet home in the trench."

-WW1 British poem




and answer:

Hello,

i did not associate the "bugs and Howlers" thread with proposals for SH5, i'm seldomly here, sorry

"..
So it is your contention that the best possibility of escape for a submarine was to stay at periscope depth and run silent?
.."

Regarding Active Sonar: in anything but calm seas, yes. But even in calm seas the possibility of being detected by active sonar is quite low, at least until the very late 1940ies. No protruding sonar dome sending waves upwards, or at least parallel to the water surface. This would require a deep-positioned sonar much below the keel, or in a drop-shaped bow which was not commonly used before the 1950ies.

" ...Active sonar may or may not sense submarines at periscope depth, but active sonar does not depend on how much noise the submarine is making. ..."

The only possibility for a detection at pd is a reflective layer under the current keel depth of the sub, indirectly showing an echo, or maybe a sub with a big (!) draught. The common advice "run silent run deep" will not help you against an alerted destroyer using active sonar, as long as there is no stratified temperature and/or density layer.

"... Can hydrophones not detect a submarine at a depth of 45-65 feet?
..."

Detection at PD via acoustics and hydrophone is certainly possible, but remember surface noise below all but perfectly clear water surfaces, and add this to a boat running silent at PD. You say detection was possible at 45-65 feet (i think it's more deep than that), but even a large IXB/C/D type will be only at a pd keel depth of 12 meters, which is appx. 36 feet, and thus almost undetectable if it is not directly (less than) 20 feet ahead of the active sonar/hunter.

" ... You say "read some books". Which ones? Specific quotes, please. ..."

Some of the older U-boat games like "Wolfpack" and "Das Boot" did indeed model this right, even if they were not too exact in other respect . In Wolfpack it was even mentioned in the readme or so i think ..

Real Examples:
The deeper-drafting russian Dieselboats of the cold war were undetectable in the shallow baltic, even with all their noise and more modern surface-ship sonar and acoustic equipment. No bluewater conditions in shallow waters at all here, even if the ground would theoretically serve as a reflector for sonar waves.

Erich Topp often said and wrote that he almost never dived to below 30 meters (appx. 92 feet) in his whole career, even in the open atlantic. He also stated that it was much more secure to stay at very low depths like PD because of the weaknesses of the allied ASDIC (early sonar), the sloping detection cone and surface noise down to some 30-to 40 meters (as he said) in a mildly moved sea.

Then there is a book from the early 1960ies printed in then-East Germany (which was back then an ally of Russia, until 1989), translated "U-Boats, U-boat war and detection". There is some very detailed stuff about sub detection in blue- and brownwater conditions, along with a thorough - if indirect - guide for (Russian) submarines to evade detection in the time before 1970, written by and from a surface hunter's view.
There is even a description why deeply-positioned sonar array did not find low-diving submarines until 1970, due to the reflecting water surface of almost clear and mirror-like water surfaces.
This is part of what i read, there is also some stuff in various french (e.g. Peillard) and german (wartime) publications of different U-boat commanders, like Lueth, Topp, and others.
There is also a description of evading by doing exactly this in the book "Sharks and little fish", but this is a novel (if from a witness), also a film from the 1950ies.

My post was not meant to attack someone, but let's remain realistic. Like one of those SH3 advisors (former Kapitaenleutnant Oesten) said "i would not have stood a chance if reality would have been as hard as it is modelled in the sim"
Staying at PD was a well-used tactic, even if Hedgehog and other random firing devices made it increasingly difficult for U-boats to survive.

Greetings,
Catfish


Thanks for reading and greetings,
Catfish

Maybe you should watch this Erik Topp interview.
At 5:00 he begins speaking about depth.:

[karamazovnew]

Catfish, you're right in some ways, but the kind of weather that would impact escort sensors would also make a torpedo attack impossible. In very rough weather, the biggest problem of the sensors wouldn't be wave relfections but that their platform is bouncing off like a cork (and so do you). Convoys regarded rough weather as a shield against subs.

However in normal waters here's what happens:

When surfaced:
- they can spot you visually or with radar
- they can't ping you
- they can't hear you (they can but their equipment will be overwhelmed by background noise since you make the same noise frequency as the convoy background noise and their own speed)

When at PD:
- they can spot you periscope and planes can see you if overhead.
- they can ping you (yeap, they can)
- they can hear you perfectly (because the noise you make is now of a higher frequency, amplified by contrast by the waves themselves)

When deep:
- they can ping you but at some angles the thermal layers will throw them off. They will either think you're not there, or they'll think you're somewhere else (further or closer but on the same bearing). However, when right on top of you (I mean close), their precision increases dramatically. Once an escort is DC close to you, you're in for the ride.
- they can hear you, thermal layers having no effect on bearings. But the sound waves become lower so, in effect, you can use more speed (silent running now makes you invisible to them)

So as you can see, you're most vulnerable at PD and your best bet is to go as deep as possible every time. The main reason they never went too deep was that most captains went deeper when the DC were in the water. Being at crush depth doesn't give you many options, plus, any dent in the pressure hull would kill you.