Some more manual targeting questions.

[legion78]

First of all i'm using nygm war tonnage and commander. Been trying my hand at manual targeting with mixed results. It always seems like Range and Speed are never accurate using the tools provided even at a dead stop. Does anyone have any suggestions? Can anyone give me their basic runthrough when attempting to engage a single target. Please don't give me the link to wazoo's ive read it backwards and forwards unfourtunately most of the time I don't have enough time to go through all that.

Also Ive really been trying to get a hold of that (3km Pato's Bearing and Range) overlay thats mentioned in wazoos but all the links seem to reach a dead end. Anyone have it or know where I can still get it will get a round of drinks on me.

Any chart mods or links would be appreciated.

[Mil_tera]

Did you try the 3:15 sec rule for the speed? That is working for me and not hard to master. The notepad method is not a reliable method to use for range and speed and I am not using it much.

I determine the course and range by this method.

http://www.subsim.com/phpBB/viewtopic.php?t=49376


And then use the 3.15 sec rule for speed. You also can determine the speed after identifying the target with the Hydrophone, but don't know the link for that. I will look for it though if you want me too.



http://www.communitymanuals.com/shiii/index.php?title=Three_Minute_Rule

Also make sure that you open the torpedo door before firing (Q) and that your AOB is set correctly. Ideal line up is 90Port when target is traveling from right to left, and 90Starboard when traveling from left to right.


Good luck!

[Brentano]

I wouldn't worry about range. If you have the speed, bearing, and AOB correct, entering a range figure into the TDC becomes pointless. That being said, you should always get as close as possible.

For speed, have you tried using the nomograph that comes with NYGM? It seems accurate to within +/- 1 knot.

If I'm not positive about the speed, I always fire a salvo. I set the spread degree based on approximate range and ship type. Use a tighter salvo for longer shots and smaller targets.

Keep in mind that manual targeting can take some time to learn. I was aweful when I first started. Experience and intuition can play a significant role in your success. Keep at it and you'll get the hang of it, and when you do ... you probably won't want to go back to auto-aim.

[Mil_tera]

Hi Bretano,

I didn't know that Range was not so important. So if you don't set the range when you know speed and bearing you can fire just as accurate as when you would set range?

[Brentano]

As long as I am reasonably confident about the Bearing, Angle on Bow, and Speed ... I never set the range. Manual targeting is all about geometry. If you have the angles and the speed, the distance is irrelevant.

Just so you know, I usually let my torps loose at between 750 and 2500 meters. For the fun of it, I'll send out a salvo from 5000 meters ... just to see if I'm lucky! :D

[Brentano]

Good Lord! -- "Wild Night in Bangkok"

[Threadfin]

If you have the angles and the speed, the distance is irrelevant.



I disagree. The TDC is in essence predicting the spot the target will be based on your inputs, and applying the proper lead to the torpedo to intercept that spot. The further away the target is, the longer the torpedos take to get to the target, and the more lead needs to be applied since the target has moved more in the time it takes for the fish to get there. Only in a situation where the target is stationary would the range be unimportant.

[Brentano]

I disagree. The TDC is in essence predicting the spot the target will be based on your inputs, and applying the proper lead to the torpedo to intercept that spot. The further away the target is, the longer the torpedos take to get to the target, and the more lead needs to be applied since the target has moved more in the time it takes for the fish to get there. Only in a situation where the target is stationary would the range be unimportant.

I think if you play around with the TDC, you'll find that if (1) you have the Bearing correct, (2) you have the Angle on Bow correct, and (3) you have the speed correct, then you will hit the target ... regardless of the range (of course, when I say regardless, I mean within practical limits).

In other words, if you do some proper plotting with either visual range and bearing OR sonar range and bearing, then you can set yourself up in a perpendicular position (90 degrees) to the course of your target within a practical range of, say 500 to 3000 meters. From that position, AOB is self-evident. Speed is simply distance over time. You can get speed either by measuring it outright or using a handy nomograph. Now just set the Bearing 10 or 20 degrees left or right (depending on whether the target is approaching from starboard or port) ... when the target reaches that Bearing point within the periscope or hydrophone, torpedo loss!.

Whether you disagree or not, I NEVER set the range ... because I never have to ... because I always get the Bearing, AOB, and Speed before I hit the fire button.

[Cue-Ball909]

Whether you disagree or not, I NEVER set the range ... because I never have to ... because I always get the Bearing, AOB, and Speed before I hit the fire button.How do you get a ship's bearing and AOB without knowing how far away it is? Unless you're shadowing a ship, matching it's compass heading, I don't see how you're doing this.

Please give us some more details, as I also have been trying manual targeting solutions without much luck.

[Brentano]

I have a ton of stuff to do tonight, but I'll get back to you on this. I imagine if you do a search you can find a tutorial.

Basically, think about this: If you get the bearing and range from your watch officer or sonar man and plot that position on the map, you have a fairly accurate point on the map for your target. If you do this a few times over a few minutes you have a few points on the map. Draw a line through the points and you have the course of the target. Once you have the course, it's usually easy to get in front of the target and set up for the shot by speeding off to a spot at 90 degrees to the course of the target.You can also get the speed by measuring the time between points.

I'll get back to you when I have more time.

[panthercules]

If you have decent visibility and the time to get set up for the shot, (and the target doesn't change course or speed) it actually is quite simple.

1. While surfaced and close enough to see the target without her seeing you, get your range and bearing to target (hard way = stadimeter in UZO; easy way = ask your WO); mark the target's location on your nav map, and start your stopwatch.

2. Maneuver on surface to stay close enough to see the target without her seeing you, keeping an eye on your stopwatch. As close to 3 minutes and 15 secs as you can get, get your range and bearing to target again and mark the target's location on your nav map again (as above).

3. Since any two points define a line, you can now simply draw a line on your nav map between the two target positions you just marked (extend the line out a ways beyond the target's most recent position marking, for convenience). If you aren't real sure about your position markings, start your stopwatch again right way (after getting your second position marking) and repeat the range/bearing marking in another 3min/15secs - that will give you 3 points and you can draw a line that passes most closely through all 3 points - it will be more likely to be accurate in that case.

4. The line you drew is your target's course, and the distance between the target position markers (the distance the target covered in 3mins/15secs, in .1Km chunks) is your target's speed. I.e., if your target went 1.2km between those position markers, the target's speed is 12 knots; if it went .6km, its speed is 6 knots).

5. Now plot a course that will take you up ahead of your target and wind up pointing you directly at the line of your target's course (i.e., so a line drawn straight ahead from your boat will hit the target's course line at a 90 degree angle), at whatever range you want to shoot at (usually between 500-1000 meters, though it doesn't matter all that much within reason) - just make sure to plot your course so that you stay out of your target's visual range while you are getting to your chosen firing spot.

6. A little before you reach your chosen firing spot, submerge to periscope depth and get your soundman to track your target on the hydrophones. You may want to pop up your scope every once in a while just to check and make sure the target hasn't changed course or speed.

7. You should set up your TDC at this point (manually). After selecting your desired tube(s), torp depth and speed (and spread angle if firing a salvo) and target speed settings, etc., first set your firing bearing dial needle to 0 degrees (assuming a bow shot here), then set your AOB dial needle to 90 degrees (port or starboard, depending on which side of your target will be facing you when it's straight ahead of you on its course line.) e.g., if your target will be coming along its course line from your left, its starboard side will be facing you and you would set your AOB needle to 90 degrees starboard.

8. If you look at the attack map, you should (unless some mod has suppressed it) see a dotted line that indicates the direction the torpedo would take if you actually fired it at your target when it was straight ahead of you. Of course, this line will be bending somewhat off to the side (the right side in the above example of the target coming from your left), because the ship will continue moving along its course line after you fire until the torp gets there. Depending on the target's speed (i.e., at higher target speeds), you might see that the target will get so far to the right before being hit that the angle of impact will be so small that you greatly increase the risk of a detonation failure. To address this (and here's the "magic"), just move/drag the firing bearing dial needle from 0 degrees toward the direction the target is coming from (i.e., to your left in the above example) - as you do this, you will see the AOB needle move to keep track of the correct AOB (so you don't need to guess at it) and you should see the torp path line on the attack map begin to straighten out until it points straight ahead or close enough to it to have a decent angle of impact close to 90 degrees. Depending on the target's speed, dragging the firing bearing needle over somewhere between 10-30 degrees toward the target usually works just fine.

9. Once you have dragged your firing bearing dial needle to where you want it (assume for the above example that you picked 340 degrees), open your tube door(s) and then you can just wait. Either by occasional visual 'scope checks or through your soundman, keep up with your target's bearings as they progress toward your pre-selected firing bearing needle setting. Just before your target reaches your pre-selected firing bearing, make a last look through the 'scope to ID your target's flag (if you haven't before) and make a last check to see if they look like they still haven't changed course or speed - then, when the target gets to your pre-selected firing point (340 degrees in this example), give the order - Los!

As to whether the range matters, as it turns out if you do the math you discover that it actually does not matter, as Brentano said, at least for a single torpedo shot (again, assuming your speed and course settings are spot on, and you have no issues like your torpedo running out of fuel or your target spotting the wake and having time to alter course or speed to avoid the torp). I had deduced as much from watching what happens to your projected torp line on your attack map as you dial in longer ranges on the TDC dial (i.e., it gets longer but its angle doesn't change), but I had to actually grab my calculator and crunch through some simple triangle formulas a few times to convince myself.

Obviously, if you fire a spread then the farther away the target the wider the distance between the torps will become at any given spread angle, increasing the chances that at least some of that spread will pass in front of or behind your target. And, as noted above, the effect of any errors you do make in the target's course or speed will be magnified the farther away you fire, so it still makes sense to bore in as close as you reasonably can.

Good luck and good hunting!

[Brentano]

Thanks panthercules. You summed it up nicely.

[legion78]

Thanx for all the help guys, very much appreciated. I'll attempt to put it to good use.

[Threadfin]

[quote]torpedo loss!.



Maybe it's not setting range that is causing you to lose your torpedos :)

Here's my method http://www.subsim.com/phpBB/viewtopic.php?t=49673

[Cue-Ball909]

1. While surfaced and close enough to see the target without her seeing you, get your range and bearing to target (hard way = stadimeter in UZO; easy way = ask your WO); mark the target's location on your nav map, and start your stopwatch.This is what I was getting at when I asked the question about range. You guys ARE getting the range. But if you're asking the WO then you're just doing it the "easy" way. ;) I knew that you had to be getting range *somehow*.

I wonder how difficult it was to get range in real life, because using the stadimiter with stabilization off is very difficult. I can measure three times and get three different results. I think the limited number of vertical pixels also adds to the difficulty.

[jimmie]

That's right, you cannot know the speed if you don't have a range. And most time to observe speed accurately depends on how accurate the range is. What they're saying is you don't have to need to set the accurate range in TDC, and it doesn't mean you never need the range. You DO need the range, and as accurate as possible.

BTW, I'm interested in how people handle multiple targets at a time with these methods. And in real life, it seems dead stop waiting is not practical (difficult to keep the depth) when submerged. And when on surface, the German U-boat commander book suggest not to stay but always move, and I haven't yet read a story in which the commander waiting and lurking at the ideal fireing spot. Then, doing this realistically means everything is in motion and it doesn't seem too easy unless you can get VERY close.

[Threadfin]

A simple test....


Set up a solution on the TDC. For example set the speed to 8 knots and the AoB to 90 and bearing to zero. First, set the range at 500 and check the gyro.

Next, set the range to 2500 and check the gyro. Has the gyro changed? If so, the range is important for the shot, and the difference in the two gyro angles is the amount of error you would have in your solution with a 2000 meter error in your range estimation.

[legion78]

loads of help guys, im starting to hit...ocasionally,lol. Seriously though much thanx!

[don1reed]

Here's another interesting situation...suppose your TDC was broken where range, AOB, and speed could not be entered :hmm:

...and your torpedos could only be fired straight ahead...

...then, just relying on math...

you might want to use the law of sines, i.e.,

Offset Angle of Collision (angle of lead) = ((Target speed / torpedo speed) x sin(AOB))

btw: you can determine speed by counting revs.

Cheers,

[Mil_tera]

:huh:

[don1reed]

I'm just suggesting that if you put your TDC in manual, where it doesn't function when the scope is turned, that is, all indications on zero. You've disabled the ability for the torpedos to turn, they only go straight out of the tube.

coveat: sub is perpendicular to track of target.

example:

ship speed = 8 kn.
torp speed = 30 kn.
AOB 90° green (strb)

Law of sines

Offset Angle of Collision = arcsin ((8/30)*sin(90)) = 15.5°

since the target is traveling left to right across your sight picture, when the MOT reaches 344.5° --you fire your torpedo(s).

you will score a hit no matter if the target is 500m or 5000m--provided it maintains a constant speed of 8 kn.

...also, do a search on Greyrider's sound trainer.

[Mil_tera]

Its somewhat more clear now! Thank you...I'll play around with that rule this weekend and let you know how it went...:up:

[Barkhorn1x]

Anyone know where I can find a training mission consisting of a single merchant intercept that starts off w/ a visual of say 10000 meters?

Thanks,
Barkhorn.

[scandium]

A simple test....


Set up a solution on the TDC. For example set the speed to 8 knots and the AoB to 90 and bearing to zero. First, set the range at 500 and check the gyro.

Next, set the range to 2500 and check the gyro. Has the gyro changed? If so, the range is important for the shot, and the difference in the two gyro angles is the amount of error you would have in your solution with a 2000 meter error in your range estimation.

There's another factor too (at least with gas propelled torps) which is torp speed setting: at 500 m you can use fast settings but at 2500 you'd have to run them slow, which would also increase the bearing you'd have to fire from.

In my last mission I'd setup a manual spread for a 90 deg beam shot at 600 m but realized, when the target was at at a bearing of 330 degrees and I was still 2 km out from the point of intersection and closing at only 7 knots, that my preset 600 m fast speed set fan shot would leave my torps on fumes before they even got close to the target.

At that setting the "firing point" was bearing 352 and I quickly guesstimated I'd be more likely firing at about a 1600 m range - too far for fast torps. So reset them to slow, tightened the spread, increased the range to 1600 m in the TDC, and the solution increased to a 345 degree bearing (which his bow was just passing across by this time, I got the doors open & the torps out and scored 2/3 hits with one torp going wide). The bugger kept on chugging at 7 knots though (a C2 that I had to use impact settings on, 2 m depth, because of the weather) and later I did finish him with a 2nd fan shot from 600 meters at 8 degrees bearing with both torpedoes set to fast and almost cleaved the ship into thirds (instead he split down the middle in a very pretty and explosive display). 4 torps on a C2 is overkill I know but it was immensely satisfying all the same :)

Anyway I'd say range doesn't matter much at point blank (fast torps, range <600 m) but becomes more important as it increases and with slower torpedoes. But I'm still a novice to manual targetting so this is conjecture based on limited experience.