Manual Targeting in TMO different from stock game?

[ColonelSandersLite]

Originally Posted by Gray Lensman

To make sure I'm understanding this correctly... You're just using 0 speed and 0 AOB as a setting on the TDC to get a "straight as possible" torpedo run and using your reference charts to place the scope on the correct lead angle?

Yep. Not mentioned explicitly, but to be clear, when using that method you'll want to sight the periscope at bearing 0/180 and send a range. The range you send doesn't matter, you're just telling the TDC to shoot straight with this setup.

Originally Posted by Gray Lensman

(i.e. usually 10 slow target/15 medium target /20 fast target degrees) and setting that as my target's AOB (at point of firing). Then I scope down the same lead angle allowing the TDC to make slight gyro alterations in the final firing solution.

Yeah, you got that from one of Rockin Robbins right? Nothing wrong with doing it that way either. That method has a bit more built in error correction in the event you forgot your torpedo speed setting or have the periscope pointed a bit wrong or something.

My favored method above gives a straighter gyro angle, which can yield better accuracy when shooting at long range. It is also a flatly better method in the event you don't actually know target speed and course and want to just guess the lead angle and snap a shot off when target is at some arbitrary bearing because you don't want to be fiddling with dials when you're doing that.

Both are perfectly valid.




There's a third method that combines the best of both but requires you to do more work.

First, plot the target normally and determine target speed and the track angle. For example sake, we will say track angle is 60 degrees port.

Second solve the lead angle with the lookup chart. For example sake, we will say that you need to shoot when target is on bearing 10.

Third, enter the target speed into the TDC.

Fourth, enter the target AOB for where it will be when you shoot at it. In this case, 60 - 10 means 50 degrees AOB.

Fifth, point the periscope at the aiming bearing. Bearing 10 in this example.

Sixth, just before you fire (basically just before the ship starts to cross the line is what you want), use the stadimeter to get target range and bearing.

Seventh, move the periscope back to the aiming bearing and resend range. Do not move the periscope again until you are done shooting. Shoot as you would for the other constant bearing techniques.


The downside is obviously that it's more work.

The upsides? For starters, it has exactly the same level of error forgiveness as Rockin Robbins technique above and since you're not just guessing the lead angle, the gyro angle will be very straight every time if you do it correctly. That combination makes it the most accurate method of shooting that I know. Combining this method, electric torpedoes, and map contacts enabled yields an incredible amount of accuracy even out to maximum range. Not only do I hit the ship nearly every time (baring malfunctions), I hit the exact part of the ship I was aiming at nearly every time.

The other big upside is that it allows you to more quickly change targets in a convoy attack since speed is already entered. I used this method for the 0 gyro shots in the tutorial videos you mentioned specifically because of that.

[ColonelSandersLite]

@RR
You ninjad me. How rude! :P. Of course, it's totally my fault for staying up all night and playing video games instead of sleeping and then trying to put together a detailed and factually accurate post .

Originally Posted by Rockin Robbins

If you subsequently take another stadimeter shot, it will correct the error. But why would you use wrong procedure to introduce the error to begin with?

They both introduce error actually. Your method has the target moving from the wrong position which causes the PK to change the AOB at an incorrect rate, which results in target course error. I honestly don't see that it makes a difference either way. Since the target is closing, a second reading will be more accurate and also allow you to verify your readings so it has an intrinsic value anyways.

Originally Posted by Rockin Robbins

What is easier than picking the wrong column off a chart when under time pressure?

Bah, I almost always know my lead angles like half an hour before I actually launch a torpedo :P. More seriously, I can honestly say that I have never missed a target that way. I don't know how many firing solutions I've worked with tables, but it's probably several hundred or even more so I genuinely think it's a total non-issue.


Edit: Of course, now that I've committed those words to the interwebs, I'm sure that ol' Murphy is going to come along and make damned sure I miss my next shot due to exactly that reason...

[Rockin Robbins]

Ah yes, the incredible advantage of constant bearing technique: you set up the shot first, THEN all you have to do is maneuver your boat into position. And that frequently can take a half hour.

It sure takes the time pressure off. You're only concerned with one thing at a time with no hurry. Personally, I still say unload as much workload on the machinery as possible.

What if you print your chart on an inkjet printer and a leaking periscope seal gets the paper wet. All that beautiful color ink runs for the hills and you're looking at a blank sheet of paper. Oh, nooooooooo Mr Bill!


Yes, you're right about introducing error. However AoB error is almost always less consequential than having your aiming point behind the target. The most error free technique would be to enter speed first, AoB second, then turning on the PK just before taking the stadimeter shot. Even that will have a tiny AoB error from the delay between hitting the send AoB button and hitting the send range/bearing button. The most important thing is to have the PK on before pegging the position with the stadimeter because position and speed are the most consequential errors. A 10º difference in AoB is most often inconsequential, especially if your gyro angle is less than 20º and your angle to the track is between 70º and 120º. Part of planning an effective attack is getting in the neighborhood of 90º to the track, keeping gyro angles below 20º and shooting for a torpedo track angle of about 110º (120º for a 20 knot target. We have charts for that but they're a bit hard to comprehend). Those three factors being true, you have the most error tolerant solution possible.

Errors are inevitable. Do what you can to make them inconsequential.

[ColonelSandersLite]

Originally Posted by Rockin Robbins

Ah yes, the incredible advantage of constant bearing technique: you set up the shot first, THEN all you have to do is maneuver your boat into position. And that frequently can take a half hour.

Daylight attack vs a typical 9 knot target. You get ahead and submerge when he enters visual range, about 5 to 7 miles depending on conditions. 30 mins is right in the ballpark, yeah. Of course, you can even plan your attack well before you submerge and know your lead angle even sooner. Anyone can absolutely use one of the attack plans in those tutorial videos today, and those where worked out *months* ago.

Originally Posted by Rockin Robbins

Errors are inevitable. Do what you can to make them inconsequential.

This is the exact reason I just accept that I'm going to be taking a second (and maybe a third, fourth, fifth, and sixth) reading during the course of an attack.


As for AOB error being the less significant error, it depends. AOB error translates to positional error over time. How significant that is depends on time, target speed, target aspect, and reading accuracy.

For a simple case where you're talking about taking a reading on a typical slow merchant target 750 yards away and firing immediately, it absolutely does not matter. If you're talking about taking a reading on a fast target, waiting 5 minutes to fire, and a 3 minute run time, it matters a hell of a lot more.

If attacking from a track angle of about 100 degrees, it matters a lot less than it does when attacking from a track angle of 50 degrees. Especially if it results in the PK adjusting the AOB in a manner that makes the track angle too sharp.


Since I feel pretty strongly that you should be, at a minimum, taking a second reading, if for no other reason than to verify your firing solution, I think the difference is largely academic and doesn't even actually matter in the real world.


Also, this may come as a shock, but I don't tend to keep important printed documents underneath my leaky periscope. I store them properly in a water resistant container. I fully understand that having something absorbent underneath your periscope is conducive to good health, but I would recommend you use a towel or an old T-shirt or something instead.