Torpedo speed setting question

[schlechter pfennig]

I was doing some research a while ago and ran across this on Wiki regarding the G7a torpedoes:

"The torpedo was of a straight-running unguided design, controlled by a gyroscope. The TI was of variable speed, running a distance of 5,000 m at 81 km/h (5,500 yd at 44kt), 7,500 m at 74 km/h (8,250 yd at 40 kt), and 12,000 m at 55.6 km/h (13,200 yd at 30 kt). The 44 kt setting was used only by torpedo boats like the Schnellboote on torpedoes with reinforced engine."

Since then I don't select the 44 kt speed, but that's my personal choice. I'm curious, however, if anyone else has encountered this tidbit.

[bstanko6]

I use this setting when in close. If they see the bubbles, it would be too late to evade due to the torp speed.

In a convoy attack, these settings are essential for timing your torps to hit multiple, varied, distance ships at the same time.

[stork100]

Great pickup schlechter pfennig. I also found this a few months ago and like you I now never use the 44kt setting in the interests of trying to be authentic. As to whether this information is accurate on the other hand I don't know. This "reinforced engine" variant isn't mentioned in the other variants listing, but it also says:

"44kn was to be used by S-Boote (problems with initial design lead to breakdown on motors running 44 kn, so this setting was banned until the new engine was available"

If it's true I wonder why only the Schnellboote was so equiped. Can't think of a reason.

[Fanuboat]

U boat commandant in 39 45 used high torp speedfor long distance target.

And anyway about bubbles, they where mostly attacking at night this way no one wont see any bubbles in the surface.

[Pisces]

There is a bug in the TDC that causes lead angles not to be updated when you switch between selected tubes with different torpedo types set to different speeds, i.e. T1 and T2. So it is best to set all of them to the common speed, lest you mess up your aiming. Whatever reality was like , this is more important to avoid in my opinion.

p.s. Scuttlebutt (or what is the german equivalent of navy gossip?) says it isn't so easy to modify the T1 torpedo speed controlling hardware. Atleast not on the fly. So this seems a reasonable realism limitation to do.

[Rhodes]

Pisces, do not know if I understood your last paragraph, but if it is about if the torpedo speed could be changed via the TDC or not, it could be.

The torpedo speed vt and quotient of the target and torpedo speed vgvt was entered by means of the knobs.
In the early versions of the calculator, the torpedo speed knob could be set only in three positions (30, 40, or 44 knots – the speed of the steam torpedoes G7a then in service could be set to these values, while the electric torpedoes G7e could cruise only at the speed of 30 knots). The quotient vgvt
and the torpedo speed vt were given as inputs of the multiplier unit (https://www.youtube.com/watch?v=tS7rOP4N5Q0&feature=youtu.be&t=35m50s), which calculated the target speed vg indicated by the dial. After setting the desired torpedo speed, the operator turned the knob responsible for setting the quotient of the target and torpedo speed, to make the pointer of the target speed dial show the correct value.
Thereby, instead of using the complex dividing unit for calculating the quotient, the much simpler multiplier unit could be used.
In the later version of the calculator, the target and torpedo speed were shown by the compound dial. The torpedo speed could be set to any value in the range 10 to 46 knots. This was due to adjusting the calculator’s construction for usage with the LUT and acoustic G7e torpedoes.


From: http://www.tvre.org/en/torpedo-calculator-t-vh-re-s3

[bstanko6]

Quick tip in setting several torpedoes to the same setting...

Set your TDC to salvo shooting...
Select the tubes you want.

Set the torps how you want.

Select single shooting again.

[Pisces]

I meant that the torpedo-mechanic couldn't change the speed of the torpedo on the fly in the tubes. Surely the real-life TDC could be adjusted for different torpedo speeds on demand. But I have understood from reports made here on the silent Hunter forums (by real life submariners/torpedo mechanics or those that did the research) that torpedo-mechanics would need to adjust something mechanically internal on the torpedo. This wouldn't be possible if it is already in the tube and flooded.

In the game however, you can flip the switch whenever you want. But the TDC won't calculate with the proper speed when you select a different tube with a different speed setting.

[schlechter pfennig]

I meant that the torpedo-mechanic couldn't change the speed of the torpedo on the fly in the tubes.

That's the reason I don't change pistol settings during an attack, but only prior to one, because it was a decidedly involved process to change the pistols. It wasn't as easy as flipping a switch. However, I never knew that the speed settings were just as involved, I'd always thought it has something to do with the internal gearing, or somesuch, that could be adjustable while in the tube, much the same way as depth and gyro settings were.

Thanks to you, I'll now be setting the speeds ahead of time and, if it winds up being less than optimal at that point, owell. :)

Thanks for the info! Very much appreciated! :Kaleun_Salute:

[Rhodes]

I meant that the torpedo-mechanic couldn't change the speed of the torpedo on the fly in the tubes. Surely the real-life TDC could be adjusted for different torpedo speeds on demand. But I have understood from reports made here on the silent Hunter forums (by real life submariners/torpedo mechanics or those that did the research) that torpedo-mechanics would need to adjust something mechanically internal on the torpedo. This wouldn't be possible if it is already in the tube and flooded.


I see, so the torpedo speed setting knob in the TDC was just to input a valour for calculation and didn't had any rod or connection to the torpedo.
Reading from the site I posted I got the idea of when selecting the speed of a torpedo, it was connected and so it would change directly.

[schlechter pfennig]

Something interesting about the TDC:



"The heart of the torpedo fire control system was the torpedo calculator designated T. Vh. Re. S3, manufactured by the Siemens Company . . .

The development of this calculator started around the year 1939. In 1941 it was (together with the whole torpedo fire control system) delivered to the Kriegsmarine for testing. In the same year – after successfully passing all tests – the newly manufactured calculators were fitted in the front-going U-Boats.
From 1941 when the calculator entered service, till the end of the war, there were some modifications to its construction." (http://www.tvre.org/en/torpedo-calculator-t-vh-re-s3)



The TDC which appears in-game is this TDC. But this TDC didn't enter service, according to the aforementioned article, until 1941, two years after the war started.

[Pisces]

...However, I never knew that the speed settings were just as involved, I'd always thought it has something to do with the internal gearing, or somesuch, that could be adjustable while in the tube, much the same way as depth and gyro settings were....To be honest, I might be mixing those two reasons up. My source is hear-say and from memory years old.

I have to admit that I am guilty of claiming this real-life restrictions with as much evidence as a 'flat earther' usually defends his/her's opinion. Don't take my statement serious for fact. It sounded reasonable and in line with workarounds for the game bug. But I could certainly be wrong.

[Pisces]

I see, so the torpedo speed setting knob in the TDC was just to input a valour for calculation and didn't had any rod or connection to the torpedo.
Reading from the site I posted I got the idea of when selecting the speed of a torpedo, it was connected and so it would change directly.See my latest reply. I might have mixed up the detonator pistol procedures with this topic.

[Slammin Sam]

Hey fellow submarine enthusiasts! I'm Sam, master of the high seas. I practically grew up with Silent Hunter 2, and I really enjoy learning about submarines and how they work. Happy hunting!

[Aktungbby]

Slammin Sam!:Kaleun_Salute:

[Rhodes]

See my latest reply. I might have mixed up the detonator pistol procedures with this topic.
:salute: Already saw. :up:

[sharkbit]

I disagree with the statement that the torpedo speed cannot be set without pulling the torpedo out of the tube. Judging by the excerpt below, it appears that the speed could be changed.

Here is an excerpt from the British report on U-570 following its capture:
The Calculating Instrument


74. The calculating instrument is in the conning tower close to the attack periscope. It is considerably more elaborate than the British Submarine Torpedo Director and has a large number of dials but it does not give a clear picture of the relative position of own and enemy ships as does the British instrument.


75. The calculator performs the following functions:





A. Calculation of Director Angle


Settings


(i) Torpedo speed. Three positions 44, 40 or 30 knots set by hand.


(ii) Enemy speed. 0 to 40 knots set by hand.


(iii) Inclination. Set by hand in the first instance and then corrected automatically for change of bearing. This gear must be switched off when resetting inclination by hand.

76. The resultant director angle is shown on a dial on the face of the instrument.


I've always understood that there are rods inserted into the torpedo while in the tube that adjust the various settings and are retracted prior to firing. I believe this report makes mention of them if you read through it.

There are all kinds of technical tid bits in the report.

Here is the link for the whole report:
http://uboatarchive.net/U-570/U-570BritishReport.htm

[schlechter pfennig]

I disagree with the statement that the torpedo speed cannot be set without pulling the torpedo out of the tube. Judging by the excerpt below, it appears that the speed could be changed.

Here is an excerpt from the British report on U-570 following its capture:


I've always understood that there are rods inserted into the torpedo while in the tube that adjust the various settings and are retracted prior to firing. I believe this report makes mention of them if you read through it.

There are all kinds of technical tid bits in the report.

Here is the link for the whole report:
http://uboatarchive.net/U-570/U-570BritishReport.htm

Great find! Thanks! :Kaleun_Salute:

[Rhodes]

I disagree with the statement that the torpedo speed cannot be set without pulling the torpedo out of the tube. Judging by the excerpt below, it appears that the speed could be changed.

Here is an excerpt from the British report on U-570 following its capture:


I've always understood that there are rods inserted into the torpedo while in the tube that adjust the various settings and are retracted prior to firing. I believe this report makes mention of them if you read through it.

There are all kinds of technical tid bits in the report.

Here is the link for the whole report:


Yes, as Pisces acknowledged, he confused the changing of the detonator (impact/magnetic) with the speed. The first had to be done outside the torpedo tube and directly at it, the speed could be changed via TDC, has I had posted and now you, with the report of the captured U-570.

[Pisces]

I disagree with the statement that the torpedo speed cannot be set without pulling the torpedo out of the tube. Judging by the excerpt below, it appears that the speed could be changed.

Here is an excerpt from the British report on U-570 following its capture:


I've always understood that there are rods inserted into the torpedo while in the tube that adjust the various settings and are retracted prior to firing. I believe this report makes mention of them if you read through it.

There are all kinds of technical tid bits in the report.

Here is the link for the whole report:
http://uboatarchive.net/U-570/U-570BritishReport.htmThat describes the function of the TDC, the solution calculator located in the control room. It does not say anything about the mechanical parts of the torpedo tube. I'm sorry, it does not settle this argument. [EDIT: well not this particular part. Haven't read the entire document yet.]

If someone can find evidence that there indeed was some kind of hardware in the tubes that could change the torpedo speed from the outside then I'll concede my statement completely. There should be some kind of mechanical parts to transfer the gyroangle from the TDC. But a external way of setting torpedo speed is the confirmation that we need in this argument. (or torpedo documentation mentioning a input on the torpedo side that influences it's speed)

[Pisces]

Yes, as Pisces acknowledged, he confused the changing of the detonator (impact/magnetic) with the speed. The first had to be done outside the torpedo tube and directly at it, the speed could be changed via TDC, has I had posted and now you, with the report of the captured U-570.I said I may have confused them. I'm not totally convinced I was. :k_confused:

[Pisces]

Ok, that settles it, there was a fitting to transfer torpedo speed setting in the tube: Chapter III, bottom of page 16:

Tube Fittings
Rear Doors, Caps and Shutters
11. Rear doors, caps and bow shutters are generally similar to British design.
12. The stern cap opens upward, and carries a fixed shutter which conforms to the hull shape when the cap is closed.
13. All caps are worked by hand, two operating handles being provided for each bow cap - one in rear of the tube and one in the midship gangway.
14. Flooding and Draining. Normal arrangements are fitted for blowing up and draining down between tubes and torpedo tanks (W.R.T. tanks).
15. No T.O.T. or A.I.V. tanks are fitted.

External Adjustment Fittings
16. The following external adjustment gears are provided:
Gyro angling in 1° steps.
Speed - High, medium and low.
Depth - 0-12 metres in 0.5 m. steps.
17. The gyro angling gear can be set by hand either at the gear box in rear of the tubes, or at angling gear on each tube, or by electric power from the director angle calculator.
18. The gyro angling gear is normally engaged by hand after loading, and remains locked in this position until automatically removed by the operation of the firing lever.

[stork100]

See also this excellent article which further confirms all of the above:

http://www.ubootwaffe.pl/en/u-boats/equipment/torpedo-tubes-of-german-u-boats