New kaleun; a few realism questions

Hooston · 10-01-23, 03:35 PM

I'm told by others on this forum that the Ujagd was not a uboat thing. It seems to be disappearing from recent supermods. However the basic technique of timing the target past a fixed point to get speed is valid. You really need to be more or less stationary or, at a pinch, moving directly towards the target to get a good answer.
To do the calculation you can either use one of the tools provided by various mods or simply double the target length in metres and divide by the time to pass a fixed point in seconds. This gives speed in knots since 1 knot=0.52m/s. When sober I can do the division to the nearest knot in my head.

Of course in real life it was unlikely you would know the target length as there were too many different ship types.

John Pancoast · 10-01-23, 03:54 PM

Quote:

Originally Posted by Hooston

I'm told by others on this forum that the Ujagd was not a uboat thing. It seems to be disappearing from recent supermods. However the basic technique of timing the target past a fixed point to get speed is valid. You really need to be more or less stationary or, at a pinch, moving directly towards the target to get a good answer.
To do the calculation you can either use one of the tools provided by various mods or simply double the target length in metres and divide by the time to pass a fixed point in seconds. This gives speed in knots since 1 knot=0.52m/s. When sober I can do the division to the nearest knot in my head.

Of course in real life it was unlikely you would know the target length as there were too many different ship types.

Iirc, the "going to stationary and timing the target" was not a historical method used, more of a game method.

But I can't recall exactly. Anyone else?

Hooston · 10-01-23, 06:02 PM

The "stabilized azimuth line" on the periscope was indeed used for speed estimation.

http://www.tvre.org/en/stabilized-azimuth-line

Of course SH3 doesn't have this, but as the boat keeps an unrealistic very steady course the basic periscope markings can do the job provided you don't move the periscope and steer straight.

The site linked above gives you a lot more information than you would ever want about historical procedures! Someone put a LOT of effort in!

Kal_Maximus_U669 · 10-01-23, 06:45 PM

Quote:

Originally Posted by Hooston

The "stabilized azimuth line" on the periscope was indeed used for speed estimation.

http://www.tvre.org/en/stabilized-azimuth-line

Of course SH3 doesn't have this, but as the boat keeps an unrealistic very steady course the basic periscope markings can do the job provided you don't move the periscope and steer straight.

The site linked above gives you a lot more information than you would ever want about historical procedures! Someone put a LOT of effort in!

Play in full realism in Fifi's NYGM in bad weather, let's talk again..!!
of course it remains a game... but in this mod the feeling is very well conveyed...

Negative buoyant..No Ujag.. No point.. no map attack.. no update cible... in Mod 4.4 NYGM Enhanced Hardcore « Steel Coffins edition »
Thank" s for documentation it' s interessant

John Pancoast · 10-01-23, 07:19 PM

Quote:

Originally Posted by Hooston

The "stabilized azimuth line" on the periscope was indeed used for speed estimation.

http://www.tvre.org/en/stabilized-azimuth-line

Of course SH3 doesn't have this, but as the boat keeps an unrealistic very steady course the basic periscope markings can do the job provided you don't move the periscope and steer straight.

The site linked above gives you a lot more information than you would ever want about historical procedures! Someone put a LOT of effort in!

I'm not talking about the stablized line as much as the stopping of the boat. Whether that was actually used in combat operations vs. pre-war sops. But I could just as easily be thinking of something else altogether.

And yes, I've had that site bookmarked for many years.

derstosstrupp · 10-01-23, 08:08 PM

Stopping the boat underwater in real life near the enemy at periscope depth is a recipe for disaster. A U-boat needed momentum for effective depthkeeping. The exception is the trick of “hanging the boat by the scope”, which was more of a parlor trick, if anything, and possible only in very calm seas. Certainly not something to risk near the enemy.

Correct on U-Jagd. “U-Jagd” means ASW in German. This watch was for timing closure rates for attacking a submerged sub with depth charges. I happened on the MDv for U-Jäger vessels a couple years ago and the watch’s use is fairly well described there.

derstosstrupp · 10-01-23, 08:26 PM

The method of timing a target across the line is absolutely historically accurate. The “stabilized line” feature disappeared on the Standsehrohr wartime attack scopes (big column with seat and pedals), although there is some evidence it may have been retained in some form, as the “Skizzenbuch Band E” sketch for the gyrocompass system shows a socket connection for a stabilized line even during the war. More study required there.

Commanders were provided with MDv 416, which included among many others the following table for estimating speed by this method.

Kal_Maximus_U669 · 10-02-23, 04:43 PM

Quote:

Originally Posted by derstosstrupp

The method of timing a target across the line is absolutely historically accurate. The “stabilized line” feature disappeared on the Standsehrohr wartime attack scopes (big column with seat and pedals), although there is some evidence it may have been retained in some form, as the “Skizzenbuch Band E” sketch for the gyrocompass system shows a socket connection for a stabilized line even during the war. More study required there.

Commanders were provided with MDv 416, which included among many others the following table for estimating speed by this method.

Hey derstosstrupp good evening..
I looked for MDv 416, it is indeed the manual given to the commander of Uboat MDv number 416..would you be kind enough to provide more links on it...... strange I can't find much...
I agree... in terms of the boat, it is impossible to stabilize it perfectly still... the attack and always in motion... the design of the building. ..physical laws required..besides the Germans are pioneers of the genre...a fantastic engineering...just look at the anatomical structure of the type 7 hull...far exceeds what is done in the genre of the time (a shark made for hunting)... all this without counting the evolution throughout the conflict... besides the enemies are eager to steal all this knowledge... especially on types 21... the rest of the story we know it...I criticized the American submarines John Pancoast did not appreciate it...lol...hihi
My best regards, I greatly appreciate your work as well as your YT channel...
sincerely Kal Maximus U669

kyle9154 · 10-02-23, 03:43 PM

Quote:

Originally Posted by derstosstrupp

Stopping the boat underwater in real life near the enemy at periscope depth is a recipe for disaster. A U-boat needed momentum for effective depthkeeping. The exception is the trick of “hanging the boat by the scope”, which was more of a parlor trick, if anything, and possible only in very calm seas. Certainly not something to risk near the enemy.

Correct on U-Jagd. “U-Jagd” means ASW in German. This watch was for timing closure rates for attacking a submerged sub with depth charges. I happened on the MDv for U-Jäger vessels a couple years ago and the watch’s use is fairly well described there.

And that's exactly why it was removed from the Onealex mod, yes it was historical ww2 device but only used on German ASW vessels against British and Russian subs.

Zosimus · 10-02-23, 05:42 PM

I would say that it depends entirely on how you hunt and what you're up against. If it's a single ship that is closing, it's pretty easy to get into position and just eyeball it. If it's constant distance, it's pretty easy to use a three- or four-bearing method to figure out how to intercept it.

If it's a single ship moving away, just fall into its path and you will know the course. From there, you can just go out and around to sink it.

In terms of finding the speed, this is easy. Let's assume the ship is going 30º and you don't know the speed, but you think it may be 8 knots. If so, you should lead the ship by 14º — that is to say that you should try to turn perpendicular to its course when a straight line from the ship to your vessel is 44 degrees. Another way to say that is that the ship should be 224º in your periscope as you approach submerged. If it's moving 8 knots, then it will stay exactly at 244º so if it slowly falls back to 240º then it's only going 7 knots whereas if it moves ahead to 248º then you know it's going 9 knots or faster.

You can work out these numbers easily just by using the drawing tool. For example, draw a straight line at 70º and a perpendicular line that intersects at 90º (160º). Measure back 7 knots from the intersection to represent the ship's speed in knots and then use the compass to draw a 2 knot circle. You will find that measuring from the back location to the right portion of the circle will yield an angle of 86º so if you are at exactly 86º off of the ship and you go 2 knots perpendicular, you will be on a collision course. It will be a simple matter to just slow to 1 knot or reverse a bit before firing to get at about 400-500m, which I consider the perfect range.

If it's a convoy, you can pretty easily eyeball the general direction of the convoy and get in front. As you penetrate the screens, you should easily be able to zoom in on the map and draw a line through the ships to find their exact course. If that feels like cheating to you, simply watch them through the periscope as you pass the first lane in. If you are going, let's say, true north 0º and the ships line up perfectly at bearing 275º then you know their true course is 85º and you can adjust your course to 355º to be perfectly perpendicular.

You don't need to worry about range if you're perpendicular. And you can fire at ships in front and behind you simultaneously.

10-01-23, 03:35 PM	#1
Hooston 中国水兵 Join Date: Jun 2020 Posts: 279 Downloads: 16 Uploads: 0	Ujagd is really a game thing I'm told by others on this forum that the Ujagd was not a uboat thing. It seems to be disappearing from recent supermods. However the basic technique of timing the target past a fixed point to get speed is valid. You really need to be more or less stationary or, at a pinch, moving directly towards the target to get a good answer. To do the calculation you can either use one of the tools provided by various mods or simply double the target length in metres and divide by the time to pass a fixed point in seconds. This gives speed in knots since 1 knot=0.52m/s. When sober I can do the division to the nearest knot in my head. Of course in real life it was unlikely you would know the target length as there were too many different ship types.

10-01-23, 06:02 PM	#3
Hooston 中国水兵 Join Date: Jun 2020 Posts: 279 Downloads: 16 Uploads: 0	Well, sort of... The "stabilized azimuth line" on the periscope was indeed used for speed estimation. http://www.tvre.org/en/stabilized-azimuth-line Of course SH3 doesn't have this, but as the boat keeps an unrealistic very steady course the basic periscope markings can do the job provided you don't move the periscope and steer straight. The site linked above gives you a lot more information than you would ever want about historical procedures! Someone put a LOT of effort in!

10-01-23, 08:08 PM	#6
derstosstrupp Grey Wolf Join Date: Aug 2008 Posts: 918 Downloads: 490 Uploads: 0	Stopping the boat underwater in real life near the enemy at periscope depth is a recipe for disaster. A U-boat needed momentum for effective depthkeeping. The exception is the trick of “hanging the boat by the scope”, which was more of a parlor trick, if anything, and possible only in very calm seas. Certainly not something to risk near the enemy. Correct on U-Jagd. “U-Jagd” means ASW in German. This watch was for timing closure rates for attacking a submerged sub with depth charges. I happened on the MDv for U-Jäger vessels a couple years ago and the watch’s use is fairly well described there. __________________ Ask me anything about the Type VII or IX! One-Stop Targeting Shop: https://drive.google.com/drive/folde...WwBt-1vjW28JbO My YT Channel: https://www.youtube.com/channel/UCIJ...9FXbD3S2kgwdPQ

10-01-23, 08:26 PM	#7
derstosstrupp Grey Wolf Join Date: Aug 2008 Posts: 918 Downloads: 490 Uploads: 0	The method of timing a target across the line is absolutely historically accurate. The “stabilized line” feature disappeared on the Standsehrohr wartime attack scopes (big column with seat and pedals), although there is some evidence it may have been retained in some form, as the “Skizzenbuch Band E” sketch for the gyrocompass system shows a socket connection for a stabilized line even during the war. More study required there. Commanders were provided with MDv 416, which included among many others the following table for estimating speed by this method. __________________ Ask me anything about the Type VII or IX! One-Stop Targeting Shop: https://drive.google.com/drive/folde...WwBt-1vjW28JbO My YT Channel: https://www.youtube.com/channel/UCIJ...9FXbD3S2kgwdPQ

10-02-23, 05:42 PM	#10
Zosimus XO Join Date: Jun 2014 Location: Chorrillos, Lima, Peru Posts: 401 Downloads: 3 Uploads: 0	I would say that it depends entirely on how you hunt and what you're up against. If it's a single ship that is closing, it's pretty easy to get into position and just eyeball it. If it's constant distance, it's pretty easy to use a three- or four-bearing method to figure out how to intercept it. If it's a single ship moving away, just fall into its path and you will know the course. From there, you can just go out and around to sink it. In terms of finding the speed, this is easy. Let's assume the ship is going 30º and you don't know the speed, but you think it may be 8 knots. If so, you should lead the ship by 14º — that is to say that you should try to turn perpendicular to its course when a straight line from the ship to your vessel is 44 degrees. Another way to say that is that the ship should be 224º in your periscope as you approach submerged. If it's moving 8 knots, then it will stay exactly at 244º so if it slowly falls back to 240º then it's only going 7 knots whereas if it moves ahead to 248º then you know it's going 9 knots or faster. You can work out these numbers easily just by using the drawing tool. For example, draw a straight line at 70º and a perpendicular line that intersects at 90º (160º). Measure back 7 knots from the intersection to represent the ship's speed in knots and then use the compass to draw a 2 knot circle. You will find that measuring from the back location to the right portion of the circle will yield an angle of 86º so if you are at exactly 86º off of the ship and you go 2 knots perpendicular, you will be on a collision course. It will be a simple matter to just slow to 1 knot or reverse a bit before firing to get at about 400-500m, which I consider the perfect range. If it's a convoy, you can pretty easily eyeball the general direction of the convoy and get in front. As you penetrate the screens, you should easily be able to zoom in on the map and draw a line through the ships to find their exact course. If that feels like cheating to you, simply watch them through the periscope as you pass the first lane in. If you are going, let's say, true north 0º and the ships line up perfectly at bearing 275º then you know their true course is 85º and you can adjust your course to 355º to be perfectly perpendicular. You don't need to worry about range if you're perpendicular. And you can fire at ships in front and behind you simultaneously.