German TDC

[Bubblehead1980]

Coming from the Us side of things in SH 4...


I play without map contacts most of the time and have a high hit rate. A lot of it has to do with 3D TDC and a functioning linked radar range unit in TMO, this permits realistic targeting.


Anyways, I have little to no experience in in UBoats but have jumped in. Running Dark Waters mod for SH 4. I know this is SH 3 but from videos watched there are similarities to U boat side of things and these forums are the center of expertise on U Boat sims, so asking here.



German TDC is well different....What is the function of where you can "lock" in info and it seems linked to the periscope/Uzo, but turn off to enter fire control data.


Is this a form of Position Keeper? I thought US TDC was only one with the PK. Info does not seem to update though, so dont thin a PK.




What is best method of ascertaining speed?


With map contacts off on US side, I take range/bearing readings, mark the map and time for 3 minutes...900 yards=9 kts.


I am still adjusting to using metric system lol but should time for 3 minutes 15 seconds for metric correct?


Any advice etc is greatly appreciated. I want to do manual with map contacts until I adjust to U Boats, then move on to running without map contacts.

[Rhodes]

http://www.tvre.org/en/torpedo-fire-...german-u-boats


Great info about U-boat TDC.



In game, the is a button that we the turn of the auto-update (link form uzo/periscope) and can introduce the info. When turn back on, when turning the bearing, the AOB turn also, so updated.

Normally I use the 3m15s rule.

[Bubblehead1980]

Originally Posted by Rhodes

http://www.tvre.org/en/torpedo-fire-...german-u-boats


Great info about U-boat TDC.



In game, the is a button that we the turn of the auto-update (link form uzo/periscope) and can introduce the info. When turn back on, when turning the bearing, the AOB turn also, so updated.

Normally I use the 3m15s rule.

Excellent info! Thanks.


3 minutes 15s it is. So they travel 900 meters, speed is 9 kts or do require some conversion? (sorry, metric just throws me off and I was certainly no math major lmao)

[Rhodes]

Originally Posted by Bubblehead1980

Excellent info! Thanks.


3 minutes 15s it is. So they travel 900 meters, speed is 9 kts or do require some conversion? (sorry, metric just throws me off and I was certainly no math major lmao)

From my understanding, is similar. It's 9 kn. You can do 3.15 and multiply by 10 (according with a post a long saw) but the result would be 9000=9 knots.

Now I do not know if real life is done like this or just the game.

In sh3: 3m15s - gives me 900m, it's 9 kts.

Sh4: 3m - 900 yards its 9 kts. Yes? no? nim?



In sh3, we have a almost cheat/work around and use the weapons officer. I can use it to see what mistakes I did on my data. Normally my difficulty in both games is getting the speed of target right.

But, in sh3, on the surface I use the WO, since I think of him like my first watch officer (similar to the XO/first officer on US subs) and on U-boats, they were in charge of the surface attacks, gathering the info and reporting to person managing the TDC.

[derstosstrupp]

If you want to mimic historical procedures, the main methods of getting speed were:

1. Ausdampfen: this is matching course and speed at a distance, on the surface. Can be done in game even without map contacts by carefully watching the target and adjusting own course and speed until a) the bearing no longer changes and b) the target appears to stay at the same range. To be accurate, best to do it over 30 minutes. 10 can suffice. It is most accurate at AOBs near 90, or near zero. As a sidenote, this is as you know very similar to how the US TDC was used to refine target data - adjusting the computer til bearing and range matched. The Germans just did it with their boat. Disadvantage here being no ability to refine the data once done with Ausdampfen.

2. Koppeln: this is plotting based on exact bearings and estimated ranges. The real guys were able to accurately estimate range based on how much mast was showing over the horizon and could use a Peildiopter (a pelorus) to get accurate true bearings. Also can be done in game with adequate practice estimating ranges by eye.

3. Schätzung: plain old seaman’s eye estimation, but also could include the “fixed wire” method of estimating speed by timing how long it takes for the target to transit the vertical line. They estimated length for this purpose based on an estimate of tonnage. The real guys (same as the Americans) did not rely on or have good rec manual data.

Any questions on the German TDC I’m happy to answer. Tvre.org is great but has some small errors here and there (he didn’t have all the documentation we now do when he sadly passed).

To answer your question about the position keeper, the German TDC at least from 1940 and forward, in other words the model S3, had a functionality called Lage laufend. That took advantage of the fact that every degree of bearing change equals 1° of AOB change. The computer also had direct connection to the gyrocompass and so, when told to do so, the computer would take own course changes into account as well as bearing changes such that if you kept the optics on target, the AOB would be correct regardless of own maneuvers. So you could call it AOB tracking is what it had. And then to minimize errors caused by parallax, they would strive for a zero or near zero gyro angle shot and then roughly input the range. SH games do not implement the gyrocompass connection and so own course changes will not be taken into account.

This writeup I did explains the mixture we have:

https://www.subsim.com/radioroom/sho...&postcount=209

[Bubblehead1980]

Originally Posted by derstosstrupp

If you want to mimic historical procedures, the main methods of getting speed were:

1. Ausdampfen: this is matching course and speed at a distance, on the surface. Can be done in game even without map contacts by carefully watching the target and adjusting own course and speed until a) the bearing no longer changes and b) the target appears to stay at the same range. To be accurate, best to do it over 30 minutes. 10 can suffice. It is most accurate at AOBs near 90, or near zero. As a sidenote, this is as you know very similar to how the US TDC was used to refine target data - adjusting the computer til bearing and range matched. The Germans just did it with their boat. Disadvantage here being no ability to refine the data once done with Ausdampfen.

2. Koppeln: this is plotting based on exact bearings and estimated ranges. The real guys were able to accurately estimate range based on how much mast was showing over the horizon and could use a Peildiopter (a pelorus) to get accurate true bearings. Also can be done in game with adequate practice estimating ranges by eye.

3. Schätzung: plain old seaman’s eye estimation, but also could include the “fixed wire” method of estimating speed by timing how long it takes for the target to transit the vertical line. They estimated length for this purpose based on an estimate of tonnage. The real guys (same as the Americans) did not rely on or have good rec manual data.

Any questions on the German TDC I’m happy to answer. Tvre.org is great but has some small errors here and there (he didn’t have all the documentation we now do when he sadly passed).

To answer your question about the position keeper, the German TDC at least from mid 1941 and forward, in other words the model S3, had a functionality called Lage laufend. That took advantage of the fact that every degree of bearing change equals 1° of AOB change. The computer also had direct connection to the gyrocompass and so, when told to do so, the computer would take own course changes into account as well as bearing changes such that if you kept the optics on target, the AOB would be correct regardless of own maneuvers. So you could call it AOB tracking is what it had. And then to minimize errors caused by parallax, they would strive for a zero or near zero gyro angle shot and then roughly input the range. SH games do not implement the gyrocompass connection and so own course changes will not be taken into account.

This writeup I did explains the mixture we have:

https://www.subsim.com/radioroom/sho...&postcount=209

Thank you for the detailed answer.

I will post some questions soon.

[Bubblehead1980]

Started a real career finally...


Started in September 1939...

Sunk a Queen Elizabeth Battleship in two attacks over20+ hours...she was escorting a convoy with three destroyers.


On Second patrol now, have two merchants down by torpedoes, with three torpedoes left. I've had misses but also premature explosions and suspected deep runners.


I've had some misses though, which upon analysis are attributed to issue with proper final firing bearing. I've got the speed (metric system took time to adjust to for plotting) but the weakness is the final firing bearing with german TDC.

In the US TDC, you place the crosshairs on desired impact point, send final bearing to TDC and fire torpedo, send updated bearing, fire again and so forth or place on middle or target, send bearing. Wait for five seconds, fire, wait, fire. The TDC updates the bearing constantly, the advantage of the position keeper on US TDC.


With German TDC. What is the best way to fire on final bearing for accuracy? To lock in that final bearing.

[derstosstrupp]

Originally Posted by Bubblehead1980

Started a real career finally...


Started in September 1939...

Sunk a Queen Elizabeth Battleship in two attacks over20+ hours...she was escorting a convoy with three destroyers.


On Second patrol now, have two merchants down by torpedoes, with three torpedoes left. I've had misses but also premature explosions and suspected deep runners.


I've had some misses though, which upon analysis are attributed to issue with proper final firing bearing. I've got the speed (metric system took time to adjust to for plotting) but the weakness is the final firing bearing with german TDC.

In the US TDC, you place the crosshairs on desired impact point, send final bearing to TDC and fire torpedo, send updated bearing, fire again and so forth or place on middle or target, send bearing. Wait for five seconds, fire, wait, fire. The TDC updates the bearing constantly, the advantage of the position keeper on US TDC.


With German TDC. What is the best way to fire on final bearing for accuracy? To lock in that final bearing.

Center mass of the target. The biggest advantage of the German device over the American one was the direct transmission of the bearing from the optics to the computer. Remember the German device is not position-keeping - once you ascertain the AOB, you switch “on” the TDC to update, and from then on as you follow the target, the AOB updates as the bearing changes. This is a result though of you turning the optics. This made it so you didn’t have to shoot “im Durchwandern” (meaning placing the optics on the “shoot bearing” and waiting for the target to cross). You could follow the target with the optics, the computer’s bearing is tracking with the optics, and best case you fire when the gyro is low.

So in practice in game (different than in real life since SH TDC lacks functionality):
1. Gather your data using whatever method you prefer and note it down.
2. Once on your final attack course, set up the TDC with AOB and speed and the range you will likely fire at.
3. Switch TDC to start tracking.
4. Follow the target and watch the AOB develop, adjust as necessary.
5. Watch your gyro angle on the TDC and fire when the gyro is within 20 deg of your bow, aiming at desired impact point. Low gyro is not necessary but eliminates range as a decisive factor.

In real life (not relevant to game but if curious):
At any point, even before diving to approach, place optics on target, set AOB into the computer, switch follow switch on TDC to accept bearings from optics, and turn on the AOB motor. From now on, as long as the target maintains course, AOB need not be touched again - the computer will take all own course and target bearing changes into account to maintain the correct AOB. This was the major advantage of the S3 over the previous models.

[Bubblehead1980]

Originally Posted by derstosstrupp

Center mass of the target. The biggest advantage of the German device over the American one was the direct transmission of the bearing from the optics to the computer. Remember the German device is not position-keeping - once you ascertain the AOB, you switch “on” the TDC to update, and from then on as you follow the target, the AOB updates as the bearing changes. This is a result though of you turning the optics. This made it so you didn’t have to shoot “im Durchwandern” (meaning placing the optics on the “shoot bearing” and waiting for the target to cross). You could follow the target with the optics, the computer’s bearing is tracking with the optics, and best case you fire when the gyro is low.

So in practice in game (different than in real life since SH TDC lacks functionality):
1. Gather your data using whatever method you prefer and note it down.
2. Once on your final attack course, set up the TDC with AOB and speed and the range you will likely fire at.
3. Switch TDC to start tracking.
4. Follow the target and watch the AOB develop, adjust as necessary.
5. Watch your gyro angle on the TDC and fire when the gyro is within 20 deg of your bow, aiming at desired impact point. Low gyro is not necessary but eliminates range as a decisive factor.

In real life (not relevant to game but if curious):
At any point, even before diving to approach, place optics on target, set AOB into the computer, switch follow switch on TDC to accept bearings from optics, and turn on the AOB motor. From now on, as long as the target maintains course, AOB need not be touched again - the computer will take all own course and target bearing changes into account to maintain the correct AOB. This was the major advantage of the S3 over the previous models.

Thanks for your response, I believe I understand lol. Thinking next patrol will have improved shooting.

The buttons on TDC I circled in the shots below...When "on" I noticed the periscope is "slaved" to the periscope cant input data, but when off, and can input data. After inputting data, you hit the button to be "on"?

Problem is when I do that it seems to foul the solution up.

This I believe is the source of my misses, esp on longer range shots or a maneuvering target who's bearing and angle is changing. On US side of things, I am quite skilled at hitting zigging targets, but having trouble with German side thus far. I sunk two ships by torpedo last patrol, a third by gunfire after my last bow torpedo missed astern, I believe due to bearing issue, I had the speed correct.


Also, with G7e electric torpedoes...best to fire with a lead correct? due to its slower 30 knot speed. With MK 18 electric torpedo on US side always aim just ahead of desired impact point so it will hit there.

[Pisces]

The German TDC does take care of the lead for different speed torpedoes. No need to add a manual analog measure of lead by eye-estimation. But SH3 does have a bug of not updating the lead calculation when you switch to a tube with different speed setting. Like you have tube 1 with Type 1 Steam with fast setting 44 kts (3 settings: 30, 40, 44 kts). And tube 2 with Type 2 Electric (fixed) 30 kts. Tube 2 is selected and for whatever reason you decide to switch to tube 1. It will fire the type 1 torpedo with lead for 30 kts. As a work around you need to select a different speed for tube 1 (type 1 torpedo) and back to fast speed to reset the lead calculation by the TDC. Or make it a custom to always use the slow speeds and always make sure the type 1 torpedoes are set to slow.

[Pisces]

Originally Posted by Bubblehead1980

... I noticed the periscope is "enslaved" to the periscope cant input data,...

Typo there? Periscope slaved to periscope. I'll leave it to Stosstrup to answer. He is better at this, and I am not familiar with this particular GUI mod.

[derstosstrupp]

The easiest way to do it in SH games is to calculate the AOB that corresponds to a particular bearing, place your optics there, set the AOB into the computer and then press that TDC button you have circled. Then at that point as long as the target does not maneuver, you don’t need to update AOB again. Remember though that you can’t change course either because the TDC will not take that into account in the game.

For example:
I parallel the target at maximum range and I determine its course as 000. I overhaul it until I am a decent distance ahead and I dive. I approach on course 270. Once the range is about 1000 to 1500 m I start setting up the computer for the attack. I push the “button” to allow me to input data. Since I am on a perpendicular course, I place my scope on bearing zero, set the AOB right 90, and then press the TDC’s “button” again. Now when I slew back onto the target, the AOB will be correct in the computer.

If you are not on perpendicular course, you can use the attack disc or whatever course finder you prefer, or simply math to figure out the AOB based on the bearing.

Formula is:
AOB = Own course + relative bearing - 180 - Target course
If answer is less than -180, add 360
If answer is greater than 180, subtract 360
If answer is negative, target’s bow is left

[Bubblehead1980]

Originally Posted by Pisces

Typo there? Periscope slaved to periscope. I'll leave it to Stosstrup to answer. He is better at this, and I am not familiar with this particular GUI mod.

Yes, typo.

[Bubblehead1980]

Originally Posted by derstosstrupp

The easiest way to do it in SH games is to calculate the AOB that corresponds to a particular bearing, place your optics there, set the AOB into the computer and then press that TDC button you have circled. Then at that point as long as the target does not maneuver, you don’t need to update AOB again. Remember though that you can’t change course either because the TDC will not take that into account in the game.

For example:
I parallel the target at maximum range and I determine its course as 000. I overhaul it until I am a decent distance ahead and I dive. I approach on course 270. Once the range is about 1000 to 1500 m I start setting up the computer for the attack. I push the “button” to allow me to input data. Since I am on a perpendicular course, I place my scope on bearing zero, set the AOB right 90, and then press the TDC’s “button” again. Now when I slew back onto the target, the AOB will be correct in the computer.

If you are not on perpendicular course, you can use the attack disc or whatever course finder you prefer, or simply math to figure out the AOB based on the bearing.

Formula is:
AOB = Own course + relative bearing - 180 - Target course
If answer is less than -180, add 360
If answer is greater than 180, subtract 360
If answer is negative, target’s bow is left

My problem is not the data its operating the German TDC properly but believe may just have it figured out.

Thanks for the help

[derstosstrupp]

My last post describes how to properly operate it but glad you’re sorted.