Failing to detonate torpedo

[aluc24]

Hi all,

I'm very frustrated. I started career in SH3 + GWX + several cosmetic mods, and now trying to get some renown by sinking as much tonnage as I can during my patrols with Type IIB. As you know, it has only 5 torpedoes, so every shot counts. Since it's early war, I'm restricting myself to impact pistol, because I red that magnetics are unreliable.

The situation: I found a nice juicy Large Merchant cruising at 5 knots near Easter coast of England in late evening, in moderate storm, determined his speed, course, and prepared attack in the night, 90 degree angle, 700m distance, 3 torpedoes set on impact, fast speed, 4 meters depth, 1 degree spread.

I chose 3 torpedo salvo just in case, since 1 may not be enough to sink this ship, and there might be a dud. I calculated that I should lead by 7-8 degrees.

And... No torpedoes exploded. I loaded save just before shot, re-checked my calculations, tried again. Nothing. Tried different torpedo depth - anything from 1m to 7m (didn't go lower, because target draft is 8,9m). No depth worked. Tried magnetic, set for 10,4-10,9m. Nothing. Tried approaching more closely, to 300m. No explosion. Tried aiming for bow, since it has less curvature. Nothing.

I tried this scenario 9 times. Single torpedoes, salvo, different spreads, depths, speeds, and so on. Not a single explosion.

I uploaded one of the attempts to youtube. Please tell me what I'm doing wrong. I tried every torpedo setting combination I could think of, but nothing worked. I'm positive that my angle solution is correct, and at this range and target size it shouldn't matter a lot. Except for the storm, the conditions are perfect for a successful attack. I mean, in the worst case scenario, at least 1 of 3 torpedoes should explode... During these 9 attempts. That's 27 torpedoes that didn't explode in ideal conditions. :/\\!!

P.S. Realism is set on 100%, so I can't turn on Event Camera to see what happens to my torpedoes...


http://www.youtube.com/watch?v=xTkBwbUFdQs

[GoldenRivet]

Im looking at your TDC settings on the bottom right panel of the screen.

according to those settings, at the time you fire the shot you are apparently shooting at a target with the following TDC settings

Speed: 0 knots

Bearing 000 degrees

AOB 0 degrees

Range 500 meters

this tells me that your fish are leaving the tubes aiming at nothing but open sea as they do not have the programmed data necessary to know where to go in order to hit anything. Your fish are missing astern is my best guess... probably by at least a couple of boat lengths

EDIT: seeing that you are playing on 100% realism you will likely have to input all those parameters manually.

[aluc24]

I left these settings like that on purpose. I don't like TDC. Since I need torpedoes to go straight, I left everything on 0 so that gyro angle is 0. I shoot torpedoes when target is 7-8 degrees right (coming left), so that the torpedoes go straight and impact on 0 degrees.

I could set everything up with correct numbers (tried that), but it also gives 0 degrees gyro angle, so I guess it doesn't change a thing.

[GoldenRivet]

Well by doing it that way you are sort of blind firing your fish, they are designed to steer to a preset gyro angle to "intercept" the target you've sent them after.

If i had to guess why your fish are missing 100% of the time in the given scenario its because the TDC has them launching after a ghost of a target.

I will also mention that by leading the target without the use of the TDC your torpedoes may be all hitting the target at too great an angle and glancing off.

It really is best to set in the TDC settings and then fire.

additionally, double check the draft of the target ship by reference to the ID manual in game... if this is early war, it is possible that all of your fish are running a good meter or two deeper than what you've set due to design flaws.

its best to set them to about one or two meters depth.

try formulating an actual solution to the target and locking that data into the TDC... also set your running depth shallower.

press H to go to the hydrphone station and set bearing to 000 to listen to the torpedo, you can hear if it is tracking straight or turning or whatever... if it is hitting and glancing off you will hear the "clang" sound instead of the boom

[aluc24]

Well by doing it that way you are sort of blind firing your fish, they are designed to steer to a preset gyro angle to "intercept" the target you've sent them after.

Um... Well, that's what I'm doing. Firing at 0 gyro angle, but when target is on 7-8 degrees bearing, so that torpedoes intercept it at 0 degree bearing. The target arrives on 0 degree bearing at the same time as torpedoes.

I can tell by torpedo trail they leave in water that they are going in the right direction at the right time.

Please, take a look at video again. TDC isn't locked. It shoots torpedoes straight, so I time them early to intercept the target.

I will also mention that by leading the target without the use of the TDC your torpedoes may be all hitting the target at too great an angle and glancing off.

As I said, angle is 90 degrees... The perfect one.

its best to set them to about one or two meters depth.

Tried that. Tried all depths from 1 to 7 meters.

try formulating an actual solution to the target and locking that data into the TDC... also set your running depth shallower.

Just in case, I attempted this. There was no impact (torpedo depth 1,5m).

[GoldenRivet]

Um... Well, that's what I'm doing. Firing at 0 gyro angle, but when target is on 7-8 degrees bearing, so that torpedoes intercept it at 0 degree bearing. The target arrives on 0 degree bearing at the same time as torpedoes.

Yes, that firing strategy works depending of course on the range. If you do this with a target at 3500 meters range or 2000 meters range vs 500 meters range the results are substantially different for each target.

Your game is not broken and there is no way you have been outfitted with a full compliment of dud torpedoes.

I would highly recommend you use the TDC with the correct target parameters because guesstimating the torpedo on a 0 degree bearing all the time is going to yield an incredibly low success rate.

one last thing you could do is turn on map contact updates and look at the target map screen and watch the torpedoes on the map as they move to the target.

I can almost promise you - if you are using the 0 degree bearing snapshot method at a target you are very likely missing astern, and you will very likely continue to miss astern with probably 80% of your shots or more... unless your firing at extremely close range (400 -500 meters).

and as the war progresses - especially on 100% realism, it will become increasingly difficult to get that close to any convoy target

* i will watch the video again and see if i notice anything amiss

[GoldenRivet]

ok i notice this... at first i couldnt even see your target and assumed the video was too dark on my screen - then i realized... your target almost fills the scope sight.

what do you assume the range to be? under 500 meters? are you super close?

your torpedo will have to travel a minimum of 300 meters to arm its warhead.

it is very possible you are sending a spread of three completely unarmed torpedoes into the hull of the merchant.

[vanjast]

Depth might be your problem too..
If your torp is hitting the 'curved' bottom corner of the hull.. it's the same as a wide angle (horizontal) hit, but in the vertical.. you torp will not detonate.

This is modelled and I've seen it work (or not work!!), by following a torpedo to the target. Set your depth about a metre or two shallower than the ship draft.
:up:

[Raptor]

Are your torpedo doors OPEN before you pressed the FIRE button? If not, the game engine will delay the launch while it opens the door. That delay can be enough to make you miss astern.

Assuming the doors are open, try one of these solutions to see exactly what's going on:

1) turn on the Event Camera in the Realism settings. Watch the eel as it runs to the target. See what happens when it gets there.

2) Turn off Dud Torpedoes in the Realism settings. After firing, press F6 and watch the torpedo icon move towards the target. See what happens when it gets there. You can see if it goes under the ship without hitting it, hits the curve of the keel and is deflected without exploding, or hits the target but simply fails to explode.

[Andrewsdad]

Salute !!!

I think GoldenRivet is correct in that you are too close to the target. The torps probably didn't have a chance to arm. Certainly at the distance you were there is practically no chance that they missed ahead or astern.

AD

[aluc24]

I would highly recommend you use the TDC with the correct target parameters because guesstimating the torpedo on a 0 degree bearing all the time is going to yield an incredibly low success rate.Well, I'm not guessing... I went through a lot of tutorials for no-TDC torpedo firing, and I'm using tables. For example, this table from Carnovaro's Document Collection:

http://s29.postimg.org/js6wbw2pz/torp.jpg

It says that a 44kts (fast) torpedo with target speed of 5kts requires starboard (in this case) lead of 6 degrees (see bottom right image).

I used this before. It always provides very great accuracy, because I do not need to know exact range, opposed to TDC.

one last thing you could do is turn on map contact updates and look at the target map screen and watch the torpedoes on the map as they move to the target. Well, is there a way I can turn it on for this scenario? I don't believe SH3 allows to do it while on patrol...


what do you assume the range to be? under 500 meters? are you super close?
your torpedo will have to travel a minimum of 300 meters to arm its warhead.Range is around 700 meters. Pretty sure of it. Way more than enough to arm torpedoes. By the way, I thought only magnetics need arming distance - do impacts also?

Depth might be your problem too..As I said, I tried every depth I could think of. It didn't work.

Are your torpedo doors OPEN before you pressed the FIRE button? If not, the game engine will delay the launch while it opens the door. That delay can be enough to make you miss astern.Of course.

[aluc24]

P.S. I tried to listen with hydrophone after shooting torpedoes. There is no "clang" sound.

I tried shooting from 150m distance, just to be 100% sure that torpedo solution is accurate (of course, they wouldn't arm, but they should at least hit the hull of the target). There was no "clang" sound either. Torpedo depth was 2m.

It would seem that they run through the target hull as if it wasn't there... Could this be a game bug?

[GoldenRivet]

There is the possibility that a mod conflict or corrupt file is causing the game to not register this particular ship as a solid object and thus allowing the torpedo to pass through the ship without hitting anything


what mods are you using

[GreyBeard]

Posting a complete list of all the mods you have installed might be helpful. Just my $.02 worth.

Edit: @GoldenRivet: Oops! "what mods are you using" Saw that just moments too late. Didn't mean to be redundant.

[aluc24]

Okay, here it is.


http://s18.postimg.org/a0zxsxvrd/mods.jpg

[GoldenRivet]

You could disable all the mods, try the scenario again.

if you get good hits... enable one of the mods... go into the game, try the scenario and do this over and over again until the torpedo stops going boom... whatever the last mod you enabled is - its the problem.

[aluc24]

Alright, I'll try that. I just hope that the scenario will load with these mods disabled...

If you wish, I could upload the career file with this save. Maybe you could see something I can't...

[GoldenRivet]

sounds good... we could even try that if all else fails

[BigWalleye]

AFAIK, nothing in your mod list is an obvious contributor to the problem you are experiencing. However, I have 3 observations:

1) GWX - Merged Campaign is only useful if you are planning to transition from a North Sea or Atlantic port to the Mediterranean or Pacific during the current patrol. Otherwise, it serves no purpose, offers no advantage, and greatly increases the time to reload a saved game. As the GWX documentation recommends, activate it only when needed.

2) Your OP describes using a Typ II. So there is no purpose to activating GWX - VIIC41 Player Sub. This mod is only for use when you intend to use a VIIC41 on the current patrol and serves no other purpose. Again, please check the recommendations in the GWX documentation.

3) If you have followed the h.sie's installation instructions for V16B1-Patch-Kit, then Supplement to V 16B1 contains a modified version of de_menu.txt, en_menu.txt, or both. Since Widescreen MaGui v3.4 SA, modifies both of these files, Supplement to V 16B1 should be greyed out in the JSGME dialog box image that you posted. The fact that it is not suggests that your Supplement to V 16B1 may not be set up correctly. In that case, all kinds of unexpected behaviors could result, probably including the one you describe.

BTW, are you using SH3 Commander? If so, have you ever inadvertently changed your mod list and neglected to roll back SH3 Commander first? This also can cause all sorts of unpredictable behaviors.

[aluc24]

Okay, here is career file:

http://s000.tinyupload.com/index.php?file_id=08808718798856371109

BigWalleye, thanks. I disabled both these unnecessary mods. I also fixed Supplement to V 16B1 installation. I forgot to append these new messages to the files you mentioned.

It now shows like this:

http://s7.postimg.org/6qmil63ej/mods2.jpg

I always roll back SH3 Commander... It is set on automatic rollback.

So, with this configuration, my save doesn't load anymore. Crashes the game after displaying "U-boat..." message.

[GoldenRivet]

Loaded the most recent save file in the career.

spotted the merchant on about a 043 bearing, Sonar operator providing constant updates on bearing.

locked periscope to merchant

updated TDC with the following settings

Target Speed: 5 knots
Angle on Bow: Port (red) 60 degrees
Estimated Range visually: 1100 meters

Tube one was set for high speed with magnetic trigger at 4 meters depth

Fired tube 1:

Updated TDC to a target speed of 6 knots

Tube two was set for high speed with impact trigger at 4 meters depth

Tube one found its mark and exploded just aft of the center superstructure

Tube two found its mark and exploded just forward of the center superstructure

the merchant listed to port and sank by the stern at 2006 hours

Set your tdc to those perameters and try again - this time using the TDC method with the settings i gave you above, make sure you switch the TDC back to manual before firing. Once those settings are in.. fire the fish

if you score hits, we can assume the observed range you provided (700 meters) was in error and your torpedoes missed the target astern.

[GoldenRivet]

See above post:

Repeated the test, this time i used the same TDC settings with an updated range of 1300 meters.

fired a spread of three, 0° spread angle, high speed setting with all impact triggers.

observed two impacts under the main superstructure, third torpedoe failed to detonate, assume the strike angle was too great as the ship was heaving in a heavy swell at the time i expected the impact.

this time the ship listed hard to port, slowed to a stop and sank within 15 minutes

[aluc24]

I can't try it right now, my save doesn't load anymore.

Please tell, what was the gyro angle during your shots? At what bearing did you fire? In other words, how many degrees lead did you use?

As I mentioned, by using the method I described before, range doesn't matter at all, all that matters is target speed and AOB... Or at least that's what tutorials say.

[GoldenRivet]

I can't try it right now, my save doesn't load anymore.

Please tell, what was the gyro angle during your shots? At what bearing did you fire? In other words, how many degrees lead did you use?

As I mentioned, by using the method I described before, range doesn't matter at all, all that matters is target speed and AOB... Or at least that's what tutorials say.

Dont recall the exact gyroangle but it was about 25°, both shots were off at about a 040 bearing (call it 038-040)

even on TDC the range doesnt matter... range only gives you a time to impact and lets you know how many seconds should elapse before the hit is scored. this way you can know that if it has been 35 seconds and you have not observed an impact, and the estimated time to impact was 15 seconds... you have probably missed.

I just ran it again with all TDC settings zeroed out, and fired a snapshot in a zero bearing with 7-8 degrees lead. All three torpedoes missed astern... something is off about the lead calculation.

I listened on the hydrophone to all three torpedoes running hot straight and normal, the ship sailed right past their sound signature unharmed.

[GoldenRivet]

Tried it again... same result.

I would encourage you to learn to use the TDC... it is increadibly easy with a turorial video or two, and with a little practice it will add a great deal of realism and capability to your experiences within SH3.

I have tried the snapshot bearing method you used in your attack with mixed results.

unfortunately you have to always be at a 90 degree angle to the target and as close to 0 knots speed as possible which is time consuming to maneuver into firing position, and it is not always tactically possible to get into that position easily or quickly, especially when escorts are involved in the situation.

With use of the TDC, if done properly with even modest settings, you will find that you can fire on a target from almost any position, any speed, and almost any AOB and score a hit. With experience you can setup a TDC shot in mere seconds.

I sighted the ship in your save game at 043 degrees, by the time he moved 3 degrees of bearing change i had a solution on him and scored hits within 38 seconds of having eyes on the target.

highly recommended method

[aluc24]

even on TDC the range doesnt matter... range only gives you a time to impact and lets you know how many seconds should elapse before the hit is scored. this way you can know that if it has been 35 seconds and you have not observed an impact, and the estimated time to impact was 15 seconds... you have probably missed.

If so, why turning range dial in TDC changes gyro angle? It affects torpedo trajectory...

I just ran it again with all TDC settings zeroed out, and fired a snapshot in a zero bearing with 7-8 degrees lead. All three torpedoes missed astern... something is off about the lead calculation.

This is very strange. I recognize that this 90 degree method isn't very comfortable, but I believe it is most effective for impact torpedoes, which, as I red, should be preferred in early war.
As for calculation, I used the table shown above, and also this tool provided by Matmos GUI:

http://s28.postimg.org/f7cekoxcd/sh3_2014_01_09_12_17_57_86.png

I don't know if you are familiar with it. Outer ring represents target speed x10, middle ring - torpedo speed. You turn middle ring until these points match, and x provides lead angle.
In this case: middle ring set at 44 (fast torpedo speed), outer ring - 50 (5kts x 10), and x reads 6,5 degrees.

What exactly is wrong with this method, then? I used it dozens of times with great results...

I will try my luck with TDC then, but could you comment on this method I described? Why it didn't work? Target speed is definitely 5kts, AOB is 90 degrees, more or less... Why do torpedoes miss astern?

[Mittelwaechter]

Depth setting of your torpedos may be the problem.
V16B1 requires a wind speed/wave height dependant setting to counter the possibilitiy of surface runners and wave disturbances.
If your setting is too shallow, the mod runs the torpedos at 25 meters depth to simulate the failure.
You say there are moderate storm conditions? 10 meters wind speed results in a minimum depth setting of 4.4 meters (iirc - it's been a while I played the game).
15 meters wind asks for ~ 6.5 meters minimum - often a no go for a successful attack.

Allow external view and follow (F12) your eels to observe what happens for training purposes.

[GoldenRivet]

If so, why turning range dial in TDC changes gyro angle? It affects torpedo trajectory...

Let me rephrase... it has been my experience that range has very little effect on the solution. generally speaking i have found that the TDC range only has to be your best guess +/- several hundred meters at best. This margin of error increases with range, but i have found, as long as you are within +/- 2000 meters range has little effect on the solution

This is very strange. I recognize that this 90 degree method isn't very comfortable, but I believe it is most effective for impact torpedoes, which, as I red, should be preferred in early war.
As for calculation, I used the table shown above, and also this tool provided by Matmos GUI:

I don't know if you are familiar with it. Outer ring represents target speed x10, middle ring - torpedo speed. You turn middle ring until these points match, and x provides lead angle.
In this case: middle ring set at 44 (fast torpedo speed), outer ring - 50 (5kts x 10), and x reads 6,5 degrees.

What exactly is wrong with this method, then? I used it dozens of times with great results...

I am familiar with it, and so far as SH3 goes, there is nothing wrong with it, That is the beauty of SH3... you are quite free to play the game as you wish... i honestly dont think anything of it... however from a point of view of strategy and tactics, it will become an increasingly difficult method to use against a convoy when compared to the use of the TDC to calculate a proper solution against a target from virtually any attack position. the 90° method of attack will simply become harder to execute as the war progresses. unless the player intends only on attacking merchants sailing alone after say... late 1942, early 1943.

I will try my luck with TDC then, but could you comment on this method I described? Why it didn't work? Target speed is definitely 5kts, AOB is 90 degrees, more or less... Why do torpedoes miss astern?

I cannot say with great certainty why it failed to work. all i know is that when i tried the 90° method, the torpedoes missed astern, that very well could have been in my failing to attack properly. or in my not being as familiar with the method as you are.

I will point out though that when you are 90 degrees to the target's course, and the target is moving right to left as in this scenario, and when they are on a 7-8 degree bearing the AOB is most definitely NOT 90° its probably like somewhere around 79°

AOB is most easily described as how many degrees port or starboard from a 0° bearing the target would see you, not the other way round.... ie. they would see you 30° off the port bow or 60° or 80° etc

when set into the TDC it only has to be relatively close, not necessarily exact. this becomes more true as the target range is reduced or if the target is a particularly large ship because there is a greater margin in error in firing at a massive target like an aircraft carrier.

It could have been the case that the torpedoes malfunction as described in Mittelwaechter's reply above

he says.....

Depth setting of your torpedos may be the problem.

V16B1 requires a wind speed/wave height dependant setting to counter the possibilitiy of surface runners and wave disturbances.
If your setting is too shallow, the mod runs the torpedos at 25 meters depth to simulate the failure.
You say there are moderate storm conditions? 10 meters wind speed results in a minimum depth setting of 4.4 meters (iirc - it's been a while I played the game).
15 meters wind asks for ~ 6.5 meters minimum - often a no go for a successful attack.As i do not use the V16B1 - any comment i made about it would be completely off the cuff made up, but he seems to be aware that in order to simulate the real life failure of torpedoes in rough seas the depth is reset to 25 meters if you set the depth too shallow. it is possible that he has discovered why your attack failed. - you simply set the running depth of the torpedoes too shallow for SH3's taste, and after firing they went to a 25 meter depth to simulate failure due to high waves... the torpedoes would have passed harmlessly about 20 meters beneath the ship and continued steaming onward until they quit, hitting nothing but open sea water.

[BigWalleye]

So, with this configuration, my save doesn't load anymore. Crashes the game after displaying "U-boat..." message.

Of course your save doesn't work any more. Making any change to your activated mods list will render all mid-patrol saved games unusable. (There are some very narrow exceptions, but it's easier and safer to consider this an iron-clad rule.) Only saves made while in port can be used after a change in activated mods, and even then, some mods will require a career restart anyway.

I am sorry that you changed your activated mods list without realizing the consequences. I just assumed that you would know that you have to restart the patrol. Please accept my apology for the inconvenience I caused you.

BTW, I suspect that Mittelwaechter's comment in Post #27 is the most likely explanation of your problem. Notice that GoldenRivet does not use H.sie's patcher, so he would not experience torpedo failures in bad weather. This woyuld explain why his replays of your attacks were successful, while yours, with the patch, were not. In your case, the torpedo wake would pass right through the target, but there would be no impact and no detonation, because the torpedo would be running at 25m. This seems to fit all the facts. Try turning the Torpedo Failure Fix patch off. Of course, you will have to deactivate Supplement to V16B1 before you turn off the patch, then reactivate it. This will require creating another engagement for test purposes.

[aluc24]

Mittelwaechter, what you suggest seems very probable. The storm was definitely more than 10m/s at the time. And with not too deep target draft, it is no wonder why there wasn't a "sweet spot" depth that would allow torpedoes to run without failing, and still being shallow enough not to bounce off the target.

Let me rephrase... it has been my experience that range has very little effect on the solution. generally speaking i have found that the TDC range only has to be your best guess +/- several hundred meters at best. This margin of error increases with range, but i have found, as long as you are within +/- 2000 meters range has little effect on the solution

Out of pure interest, why is that, exactly, this little effect? Because theoretically, range shouldn't matter at all, at least to my knowledge of trigonometry. Does it have something to do with torpedo acceleration to it's cruise speed after launch? Or maybe it's due to torpedo slowing down due to lesser charge in it's batteries? (not sure it's simulated)

I am familiar with it, and so far as SH3 goes, there is nothing wrong with it, That is the beauty of SH3... you are quite free to play the game as you wish... i honestly dont think anything of it... however from a point of view of strategy and tactics, it will become an increasingly difficult method to use against a convoy when compared to the use of the TDC to calculate a proper solution against a target from virtually any attack position. the 90° method of attack will simply become harder to execute as the war progresses. unless the player intends only on attacking merchants sailing alone after say... late 1942, early 1943.

I believe you. It's only that in early war, with Type IIB, I can't really find any convoys in my patrol area. Anyway, IIB is so slow and has such poor submerged range, so little torpedoes, that it doesn't make sense to go around Britain islands, possibly exhausting fuel supply... I just try to make some reasonable renown by sinking tramp steamers and medium cargo ships to get a new u-boat.
By the way, in late August, 1939, days before start of the war, I found a HUGE convoy of heavy steel - destroyers, battleships and so on - sailing towards Germany from England. No cargo ships. Just war machines. That was some monstrous firepower, cruising at around 15 knots. Maybe I could have sunk one (there were good conditions), but England was still neutral...
Just saying. It's amazing that the game has historical ship routes. Or it seems so - it's logical that England would send a fleet of destroyers towards Germany in the eve of the war.

I will point out though that when you are 90 degrees to the target's course, and the target is moving right to left as in this scenario, and when they are on a 7-8 degree bearing the AOB is most definitely NOT 90° its probably like somewhere around 79°

That's correct, I'm aware of that. By the definition of the method, 90° angle should be at the torpedo impact point, NOT on the point of launch.

BTW, I suspect that Mittelwaechter's comment in Post #27 is the most likely explanation of your problem. Notice that GoldenRivet does not use H.sie's patcher, so he would not experience torpedo failures in bad weather. This woyuld explain why his replays of your attacks were successful, while yours, with the patch, were not. In your case, the torpedo wake would pass right through the target, but there would be no impact and no detonation, because the torpedo would be running at 25m. This seems to fit all the facts. Try turning the Torpedo Failure Fix patch off. Of course, you will have to deactivate Supplement to V16B1 before you turn off the patch, then reactivate it. This will require creating another engagement for test purposes.

This seems very logical. After all, I used this attack method dozens of times with great success. And even if there was a tiny error in these measurements, at this distance and size of the target, it shouldn't matter. I guess the storm is to blame. Next time, I'll have to stick with magnetics, since they can run deeper, or just follow the target until weather clears up.

I am sorry that you changed your activated mods list without realizing the consequences. I just assumed that you would know that you have to restart the patrol. Please accept my apology for the inconvenience I caused you.

There is nothing to apologize for :) This was the second patrol of the career, only one tramp steamer sunk. No big deal. It was way more important to find out why the attack fails in general, rather than to succeed this particular attack. Ruling out mod interference was important. I restarted the patrol from the save in harbor. No harm done.

So, I guess the mystery is solved. No way to check it, but it's the only theory that fits the facts. Thank you all very much for your help.

P.S. GoldenRivet, you said you acquired all necessary info for attack in time it took for target to move 3 degrees. I wonder how. You said that range is estimated visually. Stadimeter, or just eye-ball guess?
Speed - did you use hydrophone to calculate propeller revolutions, or again, educated guess?
AOB is most interesting. How did you go about that? I always have a problem estimating AOB without drawing a lot of stuff on the map, which takes time - so I assume you have some faster way to do it?

Please, share your methods :)

[GoldenRivet]

Out of pure interest, why is that, exactly, this little effect? Because theoretically, range shouldn't matter at all, at least to my knowledge of trigonometry. Does it have something to do with torpedo acceleration to it's cruise speed after launch? Or maybe it's due to torpedo slowing down due to lesser charge in it's batteries? (not sure it's simulated)

The trig you refer to is an equation for a perfect triangle... Bearing being side a, target path being side b and torpedo path being side c. The firing solution for our torpedoes does form a triangle however the triangle is not a perfect triangle... one corner of the triangle is an arc

this is because the torpedo has to accelerate out of the tube and then make a turn of anywhere from 0° to +/- 150°thus the base of the triangle is not an angle... it is a curve, so there is a bit more to it than a triangular equation

P.S. GoldenRivet, you said you acquired all necessary info for attack in time it took for target to move 3 degrees. I wonder how. You said that range is estimated visually. Stadimeter, or just eye-ball guess?
Speed - did you use hydrophone to calculate propeller revolutions, or again, educated guess?
AOB is most interesting. How did you go about that? I always have a problem estimating AOB without drawing a lot of stuff on the map, which takes time - so I assume you have some faster way to do it?

Please, share your methods :)

I used the T.L.A.R. method

"That Looks About Right" :haha:

It was a quick judgement call that comes from playing SH3 on a near daily basis in some form or another from March of 2005 through to the present day.

I eyeballed the range, as players get more experienced they become used to seeing ships at various ranges... i just did a quick estimate of 1,000 meters and dialed in 1100 into the range dial. I was apparently off by a few hundred meters as the impact came about 8 seconds before the clock said it was due

Speed i assumed about 5-6 knots. When a hydrophone operator reports "moving slow" it is my experience that this is anywhere from about 1-6 knots. if he reports medium speed this is generally in the ballpark of 6-11 knots, moving fast is anywhere upwards from 11+ knots just in my observations. Looking through the scope, i saw the ship cutting a pretty decent wake on its bow, so i assumed he was at the higher end of what the game considers "slow" and so I dialed in 5 knots

As for AOB, i used to draw a lot of stuff on the map, but eventually graduated up to turning map updates off, i then would take range and bearing observations and use an actual pencil, ruler, paper and protractor to plot the ship on paper to arrive at the requisite numbers for the firing solution. While it offered a neat challenge, it was time consuming to do it this way. I eventually stopped doing that with enough experience to estimate the AOB visually with about a +/- 5°-10° margin of error and when you are firing inside a range of 1KM the margin of error there is pretty loose. On a long range shot at a higher value target like 3KM range at a massive battleship or a huge liner i will just whip out a paper and do it old school

so yes... i more or less brought up the TDC... plugged in the numbers that looked about right to me and fired the shots.

from the time i looked in the scope at the target to the time i ordered the shots fired was perhaps 10-15 seconds. tops

[GoldenRivet]

Addendum to the above post


I would turn map contacts ON if i were you and get some practice with the TDC.

there are two things folks have trouble with when using the TDC

solving for speed

solving for AOB

fortunately both are actually ridiculously easy :up: thats why the Kriegsmarine put the TDC in there so any 20 year old German kid could set it up and sink a ship

Solving for speed:

1. come to a dead stop as close to 0-1 knots as you can

2. find your target in the scope, put the vertical cross hair slightly in front of the ship

3. when the ship's bow moving through the view first touches the vertical cross hair start your timer, stopwatch, wristwatch whatever

4. without moving the scope, keep looking. when the stern of the ship passes the cross hair just stop the timer.

5. look at the ship in the recognition manual (hopefully you took a moment to ID her) you will see measurements - you need to know the length of the ship

6. so lets assume a couple of things. the ship is 180 meters long, and it took 34 seconds to cross your scope's cross hair.

take 180 and divide by 34

this gives you a result of 5.29

convert that to knots by multiplying 5.29 x 1.95 (a set number which never changes)

5.29x1.95= 10.315 knots (round it to 10 even)

speed is 10 knots set that into the TDC and you're done with speed

just be sure and keep your scope low in the water in broad daylight good weather attacks to keep it from being spotted. Lower it near completely when you are not looking through it

----------

AOB is also super easy when you have map contacts enabled, i am a supported of map contact updates for the sole purpose that you are a 3 dimensional being interacting with a 2 dimensional simulated world that wants to be 3 dimensional but cant... a lot of situational awareness is lost in the visual translation and map contacts turned on really helps to make up for that.

here is my AOB tutorial video on youtube that you can watch when you have 3 and a half minutes to spare :salute:

http://www.youtube.com/watch?v=g1moVghX_SE

[BigWalleye]

You said that range is estimated visually. Stadimeter, or just eye-ball guess?
Speed - did you use hydrophone to calculate propeller revolutions, or again, educated guess?
AOB is most interesting. How did you go about that? I always have a problem estimating AOB without drawing a lot of stuff on the map, which takes time - so I assume you have some faster way to do it?

Please, share your methods :)

Here are two PDFs which describe methods for accurately determining range, AOB, and speed using the graticles found in actual WW2-vintage periscope optics.

German Optics, by Hitman, is found in the documentation section of the Hitman’s Optics mod. You can download it here: http://www.subsim.com/radioroom/downloads.php?do=file&id=1519

UJadg Tools, by joe grundman, is found in the documentation for the hsGUI mod. Download it here: http://www.subsim.com/radioroom/downloads.php?do=file&id=1648

Both links are currently active.

Hitman’s work is a unique, well-researched and documented description of the optical systems actually installed in Uboats during the war. He uses contemporary sources and personal examination of surviving periscopes from WW2 Uboats. His conclusions are sometimes ignored, but I have never seen them disputed.

joe grundman’s work provides step-by-step instructions for calculating range, AOB, and speed using graticles and either the AOB ring or the angriffsscheibe, tools which were actually available on WW2 Uboats.

In my experience, the use of graticles for angle measurement is at least as accurate as the stadimeter. And it requires no apriori positive ID of the target, although target ID can ensure a more trustworthy result. (Historically, target identification was the work of an identification party, not the Approach Officer. He merely called out descriptive features to the ID party, who looked through the book. According to first-person accounts, a positive identification of the target sometimes wasn’t made until well after a successful attack.)

These methods use tools similar to those which were present on actual Uboats. Operationally, they are neither more nor less historically appropriate than stadimeters and computer-generated speed estimates, because the Approach Officer did not do all the calculations himself. How you prefer to simulate the working of the approach party (8-10 officers and senior ratings, each with specific responsibilities) is a matter of your personal taste. AFAIK, there is no way to accurately simulate the tasks of the Approach Officer with SH3 and any combination of mods. (Or with SH4 or SH5 either.)

That said, SH3 is still, IMO, the best and most immersive sub sim ever published.

[aluc24]

"That Looks About Right" :haha:
from the time i looked in the scope at the target to the time i ordered the shots fired was perhaps 10-15 seconds. tops

Well that is pretty amazing. I guess there is no substitute for experience! I wouldn't dare relying on TLAR with so little experience I have, and so few torpedoes (a few misses, and I can go home with no tonnage sunk), but I'll always compare gut feeling with actual numbers to learn!

About your solving for speed method - it seems very handy, however, I believe it is perfectly accurate only when AOB is 90 degrees, right? And if AOB is 45 degrees, I should divide the final speed by 2, correct? Correct me if I'm wrong, but I just thought, if target is approaching with AOB like 15 degrees, it will take a lot of time for bow and stern to pass the crosshair...

AOB is also super easy when you have map contacts enabled, i am a supported of map contact updates for the sole purpose that you are a 3 dimensional being interacting with a 2 dimensional simulated world that wants to be 3 dimensional but cant... a lot of situational awareness is lost in the visual translation and map contacts turned on really helps to make up for that.

I have played with map contacts for some time, however, I found it way too easy... It makes advanced plotting techniques redundant. Two observations from periscope, and you basically know everything you need... What you say about dimensional differences is true, but I somehow feel that second case would still be more realistic... And more challenging.

For now, I'm learning to determine target speed and course solely with hydrophone. I can get decent results while being stationary, but moving 4-bearing method is still over my head.
And for actual attacks, I still rely on watch officer's range estimations. That won't be of much use later in the war, when I encounter convoys, so I'm working on hydrophone interception methods...

Your tips and techniques are very interesting and useful. Thank you. The tutorial is neat. Nice choice of music :D By the way, what is magical about 55 degree AOB? Why did you chose it, why not go with 90 degrees, since it would only require waiting a few minutes?

[GoldenRivet]

About your solving for speed method - it seems very handy, however, I believe it is perfectly accurate only when AOB is 90 degrees, right? And if AOB is 45 degrees, I should divide the final speed by 2, correct? Correct me if I'm wrong, but I just thought, if target is approaching with AOB like 15 degrees, it will take a lot of time for bow and stern to pass the crosshair...

The method works for virtually any angle on bow from about 30-120°

no further division needed.

Another method i used was to place a protractor at the bottom of a sheet of paper, trace the arc and mark the bearings in 10 degree angles with tick marks for 5 degrees from 270 through to 0 to 90.

In the game i would ID the ship, take 3 range estimations through the stadimeter and average them.

I would then use a pencil and ruler (assuming each 1/4 inch on the ruler to be 100 meters) abd u would draw the bearing line to the estimated range on paper.

I would then start my timer and wait about 2 minutes and repeat the process with updated information.

finally i could use the ruler to estimate how far the ship traveled by measuring the distance between observation point 1 and observation point 2 and mathematically determine the speed with the given distance and time.

however the time divided by ship length x 1.95 works for any reasonable firing angle


what is magical about 55 degree AOB? Why did you chose it, why not go with 90 degrees, since it would only require waiting a few minutes?

because 55 degrees was the AOB at the time of the observation and it allowed me to engage the target immediately without waiting. The torpedo automatically knows which way and how far to turn in order to steer itself to the target as close to a 90° impact as possible without you having to be close.

in a convoy situation when you want to send torpedoes at multiple ships, once you determine the AOB for each ship it is a matter of aiming at one, setting aob, firing and aiming at the other setting the new aob and firing. with practice, there is no reason you couldn't engage 5 targets with 5 torpedoes in a span of 15-20 seconds.

You could engage 3-5 targets and dive away before the fish ever hit without having to wait for each individual ship to reach 90° because after the first impact they are going to begin zig-zagging and the liklihood of subsequent misses increases dramatically - if you time it right by aiming at the furthest ship first, updating AOB and shooting, then aiming at the next closest ship, updating AOB and firing and repeating this process for subsequently closer ships... in theory you could hit all the targets at roughly the same time - or at least within the same 5-10 second window.

the advantage to not having to wait for each target to hit 90 degrees is that you can be 3 KM away from the convoy and in deep water before the first hits ever strike, and when they do... its very hard for escorts to find you, a skill that WILL become vital as the war progresses

[aluc24]

These are also interesting methods, thank you for sharing. By the way, why didn't you plot it all in SH3 map? It seems more handy than paper and pencil... Although I don't know about accuracy.

By the way, off-topic question: is there any way to fast-scroll through Ship Recognition Manual? Sometimes I know which page I should be looking at, but it takes a lot of time to mouse-click arrow button on the Manual to get to it. Is there a keyboard shortcut, or something? My mouse hurts from all that clicking...

[GoldenRivet]

These are also interesting methods, thank you for sharing. By the way, why didn't you plot it all in SH3 map? It seems more handy than paper and pencil... Although I don't know about accuracy.

way more handy than a pencil and paper, but the ruler tool in SH3 is not super accurate. Which is why i used paper

By the way, off-topic question: is there any way to fast-scroll through Ship Recognition Manual? Sometimes I know which page I should be looking at, but it takes a lot of time to mouse-click arrow button on the Manual to get to it. Is there a keyboard shortcut, or something? My mouse hurts from all that clicking...

as for this... click faster is the only way i know to do it. :D

just think of back in the day... they had several recognition manuals to search through

[aluc24]

Well, I see. Thank you very much for your help and support. It was fantastic :) I just sank a target in very complicated conditions with Type IIB: a small freighter (2229 tons), running at 9 knots. Conditions - night, severe storm, 15m/s wind, fog, rain, visibility around 800m. The target got away from me before I could intercept it on perpendicular, so I ran up right behind him, caught up to 400m, and sent a magnetic torpedo at 7,5m depth towards his propeller. All done with TDC, with range, speed and AOB known. Torpedo passed the propeller, ran along the hull a bit, and broke the bloody Brit in half. Only after explosion I could finally find out what kind of ship that was (my torpedo depth was a lucky guess). Believe me, conditions were horrible, I had to come up to 150m to recognize the bastard.

Such a satisfaction. Thanks again :salute:

[GoldenRivet]

As you get more practice, it will become more and more second nature and more and more satisfying.

I just started a new career in August '39

It is now September 8th, deck gunned two small merchants and plodded around with some dolphins for a bit, starting the return voyage tomorrow due to 50% fuel reserve.

On the way back to Wilhelmshaven I'll lurk down the eastern coastal waters of Great Britain

[aluc24]

Nice! I just flak-gunned (guess I won't shoot aircraft anyway) a Granvile-type freighter, 4707 tons. Total of 11758 tons sunk with this Type IIB, and still two torpedoes left.

By the way, while still on Type IIB, is it worth spending renown for better crew, or should I just save up for upcoming VII?

[aluc24]

Well, patrol has come to an end.

Here are the results:

http://s22.postimg.org/otry1yafl/sh3_2014_01_11_02_03_48_10.png

That is total of 16466 tons. Just third patrol, in "training purpose" Type IIB. 5 torpedoes, 5 ships sunk. From clear skies to hurricane storm. Not bad for starters, huh? :arrgh!:

In other words, I am indebted to you, man. Thank you for invaluable advice you gave me.

[GoldenRivet]

Nice! I just flak-gunned (guess I won't shoot aircraft anyway) a Granvile-type freighter, 4707 tons. Total of 11758 tons sunk with this Type IIB, and still two torpedoes left.

By the way, while still on Type IIB, is it worth spending renown for better crew, or should I just save up for upcoming VII?

save up

You are for sure going to want to venture out into the western approaches... not an easy task with a type II boat