Short torpedo tutorial

[gurudennis]

I noticed that many of the players (and even full crews) entering lobbies in Wolfpack have little understanding of how to aim and fire torpedoes for effect. Below is my attempt to provide a basic tutorial on TDC operation with specific steps that - if followed correctly - should lead to a solid hit on the intended target.

Once you've acquired the target and set up a torpedo run, preferably at periscope depth on a course that is roughly perpendicular to the target (a little ahead of the target would be ideal), it's time to get busy.

1. Ensure that 3 qualified players are manning the following stations:
- dive planes (to avoid accidentally surfacing or diving below periscope depth of 12-13 meters)
- torpedo computer (TDC)
- attack periscope (AP) - you are here

2. Align the AP with relative bearing 0 degrees (optional) and instruct the TDC operator to attach the TDC to AP by rotating the knob on the top-right into upward position.

3. Identify the target if not done already, and open its page in the manual (C key). Have the TDC operator enter the length of the ship (optional) and torpedo depth (ship draft minus 2 meters is a good rule of thumb).

4. Using the AP at maximum zoom (6x), count the number of notches (centiradians) from the waterline to the top of the tallest mast of the target. Use this value and the height of the ship's mast from the manual to determine distance to target by looking it up in the right-hand version of the distance table (C key). Have the TDC operator set the distance.

5. Slow down to under 2 knots (slow or dead slow speed)

6. Line up the vertical post of the AP with the bow of the target ship and start the timer (T key). Once the ship's stern passes the vertical post, stop the timer (by pressing T again). Now, divide the length of the ship in meters by the clocked time in seconds, and multiply the result by 2. The resulting value is the target ship's speed in knots. Have the TDC operator enter the speed.

7. Estimate the angle on the bow, or AOB. This can be done by eye with some practice. Angle on the bow is the angle at which an observer on the target ship would see the attacking U-boat, if said observer wasn't oblivious to the U-boat's presence that is. For instance, if a ship is on a perpendicular course to the U-boat and passing left to right in the AP view, the angle on the bow is 90 degrees starboard. If the ship is closing with the U-boat from right to left at a steep angle, its angle on the bow could be for example 30 degrees port. With some practice, you can determine this value fairly reliably. Have the TDC operator enter this value when the vertical AP post is just fore of amidships of the target ship. Note that the AOB gets continually adjusted as you rotate the AP to account for perceived movement, so the TDC operator may need to adjust it whenever the AP operator calls out a new value manually.

8. Re-confirm all values (range, angle on the bow, speed) if necessary.

9. Place the vertical post of the AP on the target, just fore of midships. Have the TDC operator once again set the correct AOB (yes, really, it's that tedious because AOB is notoriously difficult to estimate accurately) and select a single torpedo tube (salvos and spreads are for cowards). Ask the TDC operator to confirm the angle of impact (top-left dial) and make sure that it roughly matches the expectation (it should be 5-15 degrees off the AOB to account for torpedo travel time, possibly plus or minus a multiple of 90 degrees to account for inverted viewpoint).

10. Press the spacebar to fire. Start the timer (press R to reset if necessary, then T) and have the TDC operator confirm the time to impact. Wait it out and enjoy the fireworks.

Bonus: Excel sheet for quick and precise distance and speed calculation.

With sufficient practice, the whole sequence can take mere tens of seconds. Make sure that you give yourself plenty of time on your torpedo runs by identifying the targets early and setting invariable parameters like speed early as well.

Good hunting!


Edit 1: Edited the wording to account for intended purpose of automatic AOB adjustment.
Edit 2: Corrected the error in speed calculation.
Edit 3: Added the bonus TDC Excel sheet.

[Pisces]

Originally Posted by gurudennis

...
7. Estimate the angle on the bow, or AOB. This can be done by eye. Angle on the bow is the angle at which an observer on the target ship would see the attacking U-boat, if said observer wasn't oblivious to the U-boat's presence that is. For instance, if a ship is on a perpendicular course to the U-boat and passing left to right in the AP view, the angle on the bow is 90 degrees starboard. If the ship is closing with the U-boat from right to left at a steep angle, its angle on the bow could be for example 30 degrees port. With some practice, you can determine this value fairly reliably. Have the TDC operator enter this value and keep repeating (and adjusting) it so the TDC operator can keep entering the value. Due to a bug (or inconvenient feature) in the game, the AOB gets continually and erroneously adjusted as you rotate the AP, so the TDC operator needs to constantly adjust it back....

I very much disagree that this is a bug. And not even an inconvenient feature. It is a very useful feature when you are attacking multiple parallel moving targets on different bearings. (Like as in a convoy) After setting the AOB on one specific target at a specific bearing, you turn the scope to another target and the AOB dial shows the proper AOB for that target. No need to guestimate AOB again because all members in a convoy (should) have the same course.

When the TDC operator sets the direction feed selector to Off, he can adjust the heading (=relative bearing) dial and AOB by himself (in accordance with Commander and Navigator orders). The TDC immediately calculates the target course from the set target bearing (heading dial bottom left) and AOB dial and an internal feed from the uboats compas. This target course is held internal in the TDC.

Then when the direction feed selector (top right) is turned to the AP/OP/UZO the AOB dial and bearing/heading dial change. But this is properly calculated based on the internal target course previously set by the TDC operator turning the other dials. If the periscope was turned to another direction than the TDC operator initially set his needle to, then the AOB dial will show whatever the target would look like if it were in the direction the periscope is facing currently. If the periscope is turned to the same direction as the TDC operator initially set the bearing/heading dial then that same AOB as he set will become visible on the dial.

Now, it is ofcourse possible that the TDC operator set inaccurate values while the selector was in the off-position. But once the selector is set to one of the viewing devices the operator can still set the AOB as told by the person operating the selected viewing device. This is only a correction of AOB from better or actual (visual) data. Not because of a bug or something screwing up the AOB needle orientation. The devs did a proper recreation of how the actual device operated.

[Pisces]

...Have the TDC operator enter this value and keep repeating (and adjusting) it so the TDC operator can keep entering the value. ...

What may be the cause of your perceived in-accurate AOB setting is due to the time delay between you (looking through the periscope) establishing the AOB visually, but following the target, and the TDC operator interpreting your command and setting the dial. After determining the visual AOB on that bearing you should not turn the periscopes/UZO until the TDC operator is done. Then you can turn to reacquire the target in view. And yes the AOB dial may show a different angle now, but that will be because the target is on a slightly different bearing as it is approaching or going away from your bow. (or aft if you are using tube 5)

[gurudennis]

Thank you, I suspected that this was the intent but wasn't sure.

The reason why I'm inclined to consider this inconvenient is that the angle itself is being eyeballed and subject to constant manual adjustment, more so (I contend) than the automatic adjustment will account for. Given that firing at a single target seems to be at least as common, if not more common than firing at multiple targets, I'd rather the angle stay put, thus allowing for finer intentional adjustments. Even for multiple targets, I fear this can be a source of compounding error, whereas individual solutions are less prone to this risk.

Then there's the purely pragmatic argument of this being a videogame in which (unlike IRL) it's very much possible to have the same person man the AP and the TDC. In this case the lag you mentioned absolutely does factor in, and in the worst possible way. This makes me think that the automatic AOB adjustment should at the very least be optional. After all, it's not like the TDC is 100% historically accurate as-is (see torpedo status indicators, time-to-impact indicator).

That being said, I will edit the post above to better reflect the intended doctrine. Thanks.

[gutted]

(for example, if the ship is at 45 degrees to your viewpoint, stop the timer when the vertical post reaches the middle of the ship). This is because at that angle the ship takes twice as long to clear the same distance as seen from your point of view.

that's not going to work the way you think it will.

[Pisces]

I agree (with gutted), it would take the exact same time for the full length to pass the wire, under any AOB, as long as you are capable to observe it. (and your own speed isn't dragging the line sideways away or towards the target)

When you do it right, the line should project an imaginary wall through the water not shifting sideways. It would take as much time for the target to pass through it perpendicularly as under a very shallow angle, like 20 degrees.

[gurudennis]

Yes, you're right, my geometry was off. Of course the profile is already proportionately shorter due to view angle. Who knows how I managed to score hits that way

Editing the above accordingly.

[Aktungbby]

gurudennis! Nice first posts/thread!

[gurudennis]

Thank you!

[gurudennis]

As a bonus, I added a simple Excel sheet for quick and precise distance and speed calculation. I've seen others make these before and tried to improve on the idea somewhat.

[snailer]

Originally Posted by gurudennis

As a bonus, I added a simple Excel sheet for quick and precise distance and speed calculation. I've seen others make these before and tried to improve on the idea somewhat.

Thank you for doing that!
There are so many sheets and files going around these last days that we should definitely ask for a post to include them all.

[crepon883]

Gurudennis, just wanted to thank you very much for writing this up. It's the first tutorial of this kind or guide that I've actually understood. Not that I've hit a target yet, but I tend to fire from too far away - I am not positive but I'm thinking the 1940-era (when I tend to set Wolfpack) topedoes have a max range around 10k meters...or 10k yards but afaik they're relatively close in comparison. Someone please correct me if that's wrong. The one thing I'm still trying to get right is the target range table's unit of measurement. Is is hectometers? In that case, is the TDC knob also in hectometers - and I'm a little confused as to what the standard line marking on that knob's outer circle are meant to represent. Increases of 1k meters? At some point the lines get I think much closer together, and if I wanted say a certain value i can't always figure out where i'd dial that in. Anyway - yeah if it's hectometers, am I right that 10 of those is 1,000 meters? Derp.

[Pisces]

Yes, ranges are in hectometers, in units of 100m. 10 being 1km. But you won't hit much with those torpedoes if they can go 10km. Your aiming with the TDC is not going to be good enough at those distances. You need to set quite accurate speed and AOB to be able to hit such a speck on the horizon..