torpedoes going behind target

[TorpX]

I haven't used the Sh4 TDC, so I can't help much with the details of which buttons, etc. The idea by Sharkbit is a good one, and I would even suggest using a non-moving target to eliminate target speed as a variable. If you have already done this and are still having trouble more detective work is in order. Are you trying to make your approach with only two observations? In RL often 5 or more were neccessary. I would suggest making more and checking the data generated by the position keeper. It should be close to what is on your map. When you enter the data before turning on the position keeper, how much time has elapsed? Keep in mind the range, bearing, aob are changing in real time. If you take the range and bearing, then spend a minute to estimate speed from your map, before inputting that, then turn on the PK, the TDC will be using old range and bearing data. They can change a lot in a minute. In any case, I would suggest pausing the game to look over the TDC dials to see if the data inputs/outputs make sense. If they do not, try to isolate which elements are incorrect.

[tmdgm]

I usually wait at least 5 min before pushing the red button.

I always take multiple readings. The above was to illustrate the basic steps. I was always double checking with nav map and stadimeter.

[TorpX]

Are you entering range/bearing/speed/aob data quickly? (in game time - pausing the game to do calculations is ok)

[NorthBeach]

First and foremost, Armistead's advice to check out, and become familiar with the Bag of Tricks the best basic advice.

Unless you're fine-tuning your skills at perfecting all the different methods of making an Iron Reef, forget range all together (unless of course you plan on surfacing the boat and throwing a rock at the target and need to know how hard to throw it). That TDC critter will figure out a good angle to intercept the target using only bearing, AOB and speed. As long as you're within your torpedo's range, you're good (ignoring all the variables, e.g., target detects the torpedo, duds).

You can get target course and speed at the same time. As Razark said, use the 3 minute rule (or use the nomometer, if you get distracted, as I do. Often). ID where the target is and drop an "X" on it. Start your stopwatch. After 3 minutes drop an "X" where he is at that time. Draw a line extending from "X" to "X" (and further out). There's his course. Measure from "X" to "X". The distance divided by 100 is his speed. Enter his speed into the TDC and click TWICE on the red send button (I dunno why, someone has explained it somewhere).

Let's assume he's approaching with you on his port bow...

Set your boat up at roughly 90degs to his course (270, from his aspect), giving yourself enough distance to the target course so that your torpedoes will have enough distance to arm (about 450 yds, but you obviously don't have to be anywhere near that close). Enter AOB using 90 as your base, then backing off your lead angle (say 10degs for <15 kts) for 80degs. You can fine tune it by looking at the target course dial. Enter the AOB data by clicking TWICE (see above).

Drag the range dial to any range in the neighborhood of the range the target will be when he gets to the point of intercept (within 1000 yds or so. But even that doesn't matter). Point the scope up your aiming bearing (10degs relative, looking out the scope) and send to the TDC clicking, yes, you guessed it, TWICE on little red button. Drop the scope.

You should have figured out how long the target will take to approach firing range. So, giving yourself plenty of time to make adjustments, take another peek at him to check to see that he hasn't wandered off course. If he has, adjust accordingly.

Wait. When he's about 20degs off your relative bearing, raise the scope and wait for him to cross the wire. When the parts you want to have holes in them cross the wire, push the "make hole" button. Wait again. Hear explosions. Holler like a dope until the first mate comes into the room and calls you a "jackass".

Well, that's what happens in my control room...

[tmdgm]

torpx, yup, i'm entering all that data fairly quickly within i'd say 10 seconds. I haven't paused the game. Maybe I will next time to be sure. That's the initial calc. Like I said, I'll update range as the ship gets closer.

Northbeach, yup, i'm doing all the things you mentioned in your post, except for the click twice part. That's how i know the target was speeding up/slowing down on one of my strikes because you could visually see the space between the X marks get closer and farther apart. I always setup for ~90deg and range ~500 yds.

Like i said, only thing is i don't click twice. Didn't think that was necessary as the tdc always updates the range/aob/speed when i click once (the window on the left). Also, I've had 100% success when playing the single mission practice mission i have by clicking only once. But at least it gives me something else to try.

Thanks again for all your help. I'll see if it makes a difference. Probably won't be a few weeks tho till i get a chance to get back on patrol tho... life stuff.

[Diopos]

When you "overlay" the stadimeter image on the periscope "actual" image where is the periscope's "horizon" line? (I mean the central horizontal line).


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[Armistead]

Seems to me RFB had a different way of scope measurements, but can't say, have you tried posting in the RFB mod forum and asking. That's just a guess, maybe someone here that plays RFB knows. Overall, it appears your doing the steps correctly, so that tells me info is off somewhere.

I'm more confused by these so called speed changes you see, they just don't happen unless the enemy knows you're there and goes into zigs and almost always slows down a few knots. I've never seen the speed changes you describe playing RSRD, except when after an attack and the group breaks up ships may hit many different speeds when they regroup. Course if they see your torp wake they'll adjust to dodge it. Sometimes groups change speed with a new course leg, but not go into different speeds.

[Rip]

I think you are messing up on turning the TDC on. I click it on when I take the first observation and LEAVE it on. If it isn't already on when the last range/bearing every second till you do push it induces errors. The only time I don't is when I plan on making a as it crosses the wire shot. Then I never turn it on at all. I can think of no reason not to power it on from the start.

[tmdgm]

Originally Posted by Rip

I think you are messing up on turning the TDC on. I click it on when I take the first observation and LEAVE it on. If it isn't already on when the last range/bearing every second till you do push it induces errors. The only time I don't is when I plan on making a as it crosses the wire shot. Then I never turn it on at all. I can think of no reason not to power it on from the start.

I think you may be correct.

However, i've actually given up on rfb, i'm switching to tmo. I used FOTRS for quite a while and while I did seem to be behind on my shots, I could still over compensate with the angle of torpedo and at least get 1 or 2 hits. Since I installed RFB, it's been abysmal.

So I downloaded TMO and we'll see what happens.

[Rockin Robbins]

Originally Posted by tmdgm

Here's my basic procedures when I use the stadimeter only, done this method countless times:

1) Take a range reading using stadimeter, click the send to tdc button (click only once). Verify the range updated on the left tdc window.
2) Take second range reading using stadmeter, click the send to tdc button (click only once). Verify the range updated on the left tdc window.
3) Go to speed calc and click on the button where it estimates speed.
4) Once speed (and course) is calc'd, I click send to tdc (click only once). THis is assuming the speed calc is fairly close to what I estimated on nav map. If it's not, I enter my own speed from the 3 min rule and hit send to tdc. Verify the speed updated on the left tdc window.
5) I go to angle on bow and adjust the ship to match the calc'd course on the left picture. Click send to tdc (click only once). Verify the AOB updates on the tdc window.
6) I then hit the red button to start tracking

7) As the ship gets closer, I will redo step 1 for range and sometimes double check step 5 for AOB.
8) I set torp depths
9) After final repeat of step 1 for range, I open torp doors, adjust torp angle left or right. Target is locked in sight.
10) Fire

Oh crap! That's what I was afraid of. Time for some explanation. The torpedo data computer plots a virtual target on your map. That is the impact point of the torpedoes. If your solution is valid, you'll see that impact point plotted on your attack map, an x on the stock game or the beginning of the targeting vector on TMO and RFB. What the TDC/PK does is move that virtual target in the same direction and at the same speed as the real target, changing the TDC settings automatically over time to hit it. Understand?

If you set up the TDC and then go to your attack map (use the button from your nav map screen in stock of just press F6 in TMO). There you will be able to watch the actual target and your virtual target at the same time. They should be right on top of one another, both moving at the same speed and in the same direction. If they are not, you're wasting a torpedo.

You've been wasting a lot of torpedoes. Why? Let's see what you've done.

1) Take a range reading using stadimeter, click the send to tdc button (click only once). Verify the range updated on the left tdc window.
2) Take second range reading using stadmeter, click the send to tdc button (click only once). Verify the range updated on the left tdc window.

Let's say our real target is out there traveling north at 10 knots. You do step #1. This is a two part entry, although you don't know it. You are entering the bearing and range of your target into the TDC. In effect, you've just told the TDC where it is. So it dutifully plots the virtual target right on top of the real one. Hopefully you're waiting longer than 30 seconds between step 1 and step 2 so you can get a little accuracy on that speed measurement! It is VERY sensitive to small errors and a longer length of time between the two readings helps.

So we have our virtual position plotted on top of the real one. Remember that because the zinger comes later.

3) Go to speed calc and click on the button where it estimates speed.
4) Once speed (and course) is calc'd, I click send to tdc (click only once). THis is assuming the speed calc is fairly close to what I estimated on nav map. If it's not, I enter my own speed from the 3 min rule and hit send to tdc. Verify the speed updated on the left tdc window.

OK, now we have our speed in the TDC. How long have you taken to do the speed stuff? Let's say about 15 seconds.

5) I go to angle on bow and adjust the ship to match the calc'd course on the left picture. Click send to tdc (click only once). Verify the AOB updates on the tdc window.

Looks good, you now have the target's course in the TDC. That step also took 15 seconds. This is important! You'll see.

6) I then hit the red button to start tracking

STOP RIGHT THERE PARDNER!!!!!! Your error is now in the system. Whatever you do from here on out doesn't matter.

It's vitally important what order you enter data into the TDC. Here's what happened. First you told the TDC where the target was. Fifteen seconds later you told it what speed it was moving. Fifteen seconds later you told it what direction your target was moving. Then when you hit the red button to start the position keeper, your virtual target finally began moving. Unfortunately the real target had been moving all the time. You are aimed 30 seconds behind your target!!! Ten knots is 1000 yards in three minutes, 333.3 yards per minute, 30 seconds is a 167 yard error. Your torpedoes are headed 167 yards behind your target because that is what you targeted. If it took longer to enter your data you will miss by more.

Always turn on the PK first. Then enter the speed and AoB, then lastly the range/bearing. The instant the TDC plots the position, it will immediately (and that is important) begin moving on the course and at the speed you input. Then go to your attack map. You'll see a time right next to the targeting vector. That is your projected torpedo run. If your virtual target and the real target remain superimposed for that length of time you will hit your target. If you only fire when that is true you won't miss.

Verifying your setup with the attack map is vitally important in identifying and eliminating targeting errors. Without using the attack map, you are only guessing. With it you know you have hits on the way. I don't know why nobody else teaches the importance of the order information is fed to the TDC and when you turn on the PK, but there you can see clearly why it's important and you now have a method of calculating exactly what the magnitude of the error is.

[tmdgm]

Ahh, that could be it. Thx a bunch!!! Can't wait to give it a try.

Only thing, when you say hit PK first. Is that before the very first reading (my step 1)?

[Rockin Robbins]

It is only necessary that you turn on the PK before you do the range/bearing sighting but I always do it first so I won't forget it, as I do several attack methods that don't use the PK. When I hit it first I remember.

Yes, there are hidden stories of failure behind that advice...

[tmdgm]

Originally Posted by Rockin Robbins

It is only necessary that you turn on the PK before you do the range/bearing sighting but I always do it first so I won't forget it, as I do several attack methods that don't use the PK. When I hit it first I remember.

Yes, there are hidden stories of failure behind that advice...

Yeah, but you do two range bearing sightings? The first as the reference and the second is when you get speed and AOB. Turn it on before the first or before the second.

[Rockin Robbins]

Nope. I don't use the speed calculator, as it is too sensitive to stadimeter range errors. The most important parameter for accuracy is speed. If your AoB is off by ten degrees or your range by 100 yards, it most likely doesn't matter a bit. But if your speed is off by a knot, you're going to collect misses.

Calculating a parameter where accuracy is critical (speed) from two other parameters for which accuracy is not critical (range and AoB) is a recipe for failure every time. The only time I will use the calculate course and speed function is if there simply isn't time to do anything else. Even then, if I use the infernal function I won't shoot from outside 750 yards. The speed calculator is a solution that is much worse than the problem it attempts to solve.

Speed and target course should be determined before you even move your sub into position for the attack. I always use the 3 minute rule or other similar relationship between distance and time. That gives you plenty of time to verify and refine your numbers. As you compare predicted position with actual position while you position your boat to the target track for a nice close firing point. If you develop speed and course data from radar depth, you can get all the information you need ten or twenty minutes before you fire. If you don't have radar, you'll have to do it from periscope depth and continue refining your data until he's close enough to worry about being seen. Then you can do the rest of the attack submerged. You don't even need to raise the scope again if you don't want to. You can verify his bearing by sonar to see that he hasn't changed course and speed.