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Old 03-12-16, 07:50 PM   #16
siege00
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Here's a whole bunch of theorizing about why both methods would work.

I don't have all the maths behind it but from calculating and sketching these are my theories (not proofs).

1) Derstosstrupp's implementation of the (ausdampfverfahren) method works by simulating that the target is at a 90° angle on the bow. If you draw the triangle from yourself to where the target would be at 90° AoB, the torpedo path passes through where the target actually is so you've shortened the distance that the torpedo has to travel but still along the same path and intersecting the target's path in the process. If that's accurate then the torpedo run times projected by SH should be wrong since the target isn't actually making the triangle that the TDC thinks it is. It's being shorted.

2) With what the article says about how it was in practice, it's the same methodology but for an isoceles triangle instead of a right triangle. Entering that the target is running at the same speed sets a factor of the triangle. If ownship and target truly had the same speed then ownship and target should also have the same AoB (ie. forming an isoceles triangle), but since you're setting the target bearing as AoB, then the triangle is adjusted accordingly either shortening or elongating the shot.

Method 1 above uses the math directly while method 2 is a natural implementation of the math. Both still use the basic formula.

Does that make sense or did I just go too geeky? lol -- Again, I haven't proved it out on paper... just theory as to why both methods work.
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Old 03-13-16, 04:43 AM   #17
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Default Two Historical Firing Methods (Hit What You Are Aiming At Without AOB or Speed)

Yes it makes sense completely, i cannot wait to try, thanks!
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Old 03-13-16, 01:56 PM   #18
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Quote:
Originally Posted by palmic View Post
Hi derstosstrupp:

I have one question about Ausdampfverfahren (Constant Bearing to Target)

At tvre.org i red the article you referred (awesome, thanks ) and found that this method is there described a little more simple.
It says they actually used (own heading - current target bearing) for target AoB and own speed for its speed. This way you dont need to calculate law of sine for 90 degrees AoB as you described.

Does your solution here have some advantage? For instance - you dont need to set accurate distance to TDC? Thanks
Hi palmic,

You're right, the article doesn't expressly mention using 90 deg AOB for the Ausdampfverfahren method. It's really a matter of taste - you can either use the collision bearing as a proxy for AOB, which eliminates the need to compute "target speed" using sines (I.e. own speed x sin(target bearing)), or use 90 deg AOB, in which case the above formula would be necessary.

To answer your question about advantages: What may prove difficult with just using the bearing as AOB is the relative difficulty of entering the exact bearing into the AOB dial of the German TDC, as it only displays in 10s of degrees. 90 deg is easier to input exactly on the dial.
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Old 03-13-16, 02:10 PM   #19
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Awesome, thanks again
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Old 03-15-16, 08:12 AM   #20
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Default Two Historical Firing Methods (Hit What You Are Aiming At Without AOB or Speed)

I am glad to tell you these works even in SH5 TWOS, right now i hit Cimarron tanker from his starboard by the second moving bearing method (the less accurate one) with critical hit.

Its awesome because with this you can hunt ships even if you was spotted (and they returned to some course then), or if you have not ideal position and even if you are slightly behind and submerged (and much slower than target because of that).

Scenario was:

I was spotted by aircraft near of Cimarron escorted by some corvette at April 1940 in south-west approaches area. I was informed about target about 3 days ago by radio from luftwafe, it was coming from somewhere about Liverpool.
I met them from south, but then aircraft suddenly spawned just near of me flying directly on me (bull**** - sorry, but i was very slow in about 10m wind waves, i was invisible for aircraft without radar, it could spot me by some flying around, but not before i hear it and just 10 minutes after emerging).

So my target changed its course and it literally made circle clockwise.

Then i was catching him up from west, his course was about 185 degrees, just like my.
I changed my course to somewhat 125 to be for about 60 degrees angle on track.
Then i was just waiting and going full at 15.5 knots emerged.
His escort started firing on me from about 7km away, but it stayed before the tanker, to not letting him alone, so i just submerged and stayed in my way to shooting position.
After some 20 minutes, i was there - about 110 degrees AoB as you can see roughly by eye, about 6000m away as you can see at RAOBF (his mast height is 30m as you can see - 6km at RAOBF is 60 left - at 30 which is his mast height).

Then i've just done Auswanderungsverfahren (Change in Bearing of Target Over 1 Minute), added all to TDC, moved periscope cross to him and fired one magnetic 2 meters under the keel just in the middle of bow and one with impact pistol on the front.. (the second image of link above).

The Eels was travelling to 6km, so i set it to medium speed (max distance 7.5km) and waited for about 3m time.

I play at full realism without external nor effect cameras, so i was just able to hear the torpedos and tanker in hydrophone, everything seemed accurate..

It was about 20% of time left to impact and suddelny it happend - Torpedo trefa!
(so he was just about 5500m away...)

the first magnetic torpedo exploded somewhere bellow him and broke him in the middle. Then we was just about to see beautiful fireworks of full Cimarron tanker
Second one had ran around somewhere before him...
After short show, i was sneaking away before escort sprinting to my position....

This all was about 4hours operation in real life time, no special TC, i was maneuvering to his position, then closing up... so i enjoyed the hit a lot
UPDATE: And after lets say 10 minutes, listening sinking Cimarron, unplesant distraction came over me

Last edited by palmic; 03-19-16 at 03:10 PM.
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Old 03-15-16, 09:02 AM   #21
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I'm going to have to spend some time in sub school and practice all 3 methods. More tools for the toolbox.
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Old 01-05-22, 10:38 AM   #22
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Default quick hint

I was thinking about how to use it immersively just on paper, or even in head and found easy helper for Auswanderungsverfahren.

When you calculate distance with bearing change into resulted speed modification where author of tutorial video is converting from metric system into speed (knots), just use 10 for every 300m of distance.

His distance was 1000m and he calculated in calculator result of 33.
By this hint 1000m is 300m * 3.3, so 3.3 * 10 as i said is the same

Sinus is 0.1 for every 6 angles from zero to about 30 then its a little different, you can print sin table from internet.
- sin(6) = 0.1, sin(12) = 0.2, sin(30) = 0.5.

In his example sin(10.5) = 0.18, so his example can be simply calculated in head like 33 * 2 / 10 minus some little portion -> 6.6 minus lets say 0.2 = 6.4.

Good enough for my TDC
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Old 01-05-22, 11:27 AM   #23
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Quote:
Originally Posted by derstosstrupp View Post
Hi palmic,

You're right, the article doesn't expressly mention using 90 deg AOB for the Ausdampfverfahren method. It's really a matter of taste - you can either use the collision bearing as a proxy for AOB, which eliminates the need to compute "target speed" using sines (I.e. own speed x sin(target bearing)), or use 90 deg AOB, in which case the above formula would be necessary.

To answer your question about advantages: What may prove difficult with just using the bearing as AOB is the relative difficulty of entering the exact bearing into the AOB dial of the German TDC, as it only displays in 10s of degrees. 90 deg is easier to input exactly on the dial.
You can use any AoB into TDC exactly, just set it to 90, lock and move periscope by (90 - your_wanted_AoB) degrees.

Its because of all triangle inner angles sums into 180.
So if you watch target moving 1 degree to the side, his AoB is changing also by 1 degree in virtual triangle solution.

Last edited by palmic; 01-05-22 at 02:21 PM.
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