[REL] 3D TDC and Radar Range Unit

[I'm goin' down]

Originally Posted by John Channing

For 1) and 3): Once you start the watch it keeps running regardless of what screen you are in. Just hit the "X" key to make it appear. But I think you might be over using the watch for some reason.

To get a speed estimate just get a range/bearing at the radar station and head quickly to the plot. Put an "X" when your boat is. Then, on a piece of paper, write down the range an bearing. Afer 3:00 mins get another range and bearing and put an "X on the map where your sub is and write down the range and bearing. Then you can take your time to plot the two measurements on the map, measure the distance between the two results, subtract the last digit and voila... speed estimate.

For 2) It's a game limitation. You just have to get diciplined about switching back to the Range setting every time you leave the Periscope/TBT.

JCC

(bold added by IGD)

razar, channing and nisgeis-

My point about plot, was that the above post only mentions the "x". If you have to include the protractor angles, then time is awasting. You might as well pause the pause to make the entries. Also, the sub is on the move, and at flank can cover a lot of ground in 30 seconds. (Check the distance for one minutes at 20 kts.). That can affect the plotting of range.

razark, I was joking about the speed calcs. I use the 3 minute rule unless I forget to look at the stopwatch, in which case I convert to seconds.

razark, I did not know changing headings might affect the radar range and bearing readings adversely. If it is true, it is a good think to know. You might as well take the first reading when you are pointed at the target, otherwise you may have reading that are accurate but you could be getting further away from it.

[John Channing]

Unless the contact is moving away from you why in the world would you be at a flank bell? If the contact is closing you at all you will want all the time you can get to get your solution up, running and refined.

JCC

[I'm goin' down]

good point. the one I am now after was at 180 degrees and heading away, so I am chasing it..

[razark]

Originally Posted by I'm goin' down

My point about plot, was that the above post only mentions the "x". If you have to include the protractor angles, then time is awasting. You might as well pause the pause to make the entries. Also, the sub is on the move, and at flank can cover a lot of ground in 30 seconds. (Check the distance for one minutes at 20 kts.). That can affect the plotting of range.

As long as you're going in a straight line, it doesn't matter how far you've gone. As long as the "X" is pretty close to where you were when you made the reading, the angle should work. Jot down your bearing, range, and time on a piece of paper, and mark your "X" on the map. You can make several fixes on the target, each with an "X" to mark your position. When you have time, you can go back, draw in the angles and ranges, and figure out speed and course, without having to worry about getting back to the radar for your next observation right away.

Originally Posted by I'm goin' down

razark, I was joking about the speed calcs. I use the 3 minute rule unless I forget to look at the stopwatch, in which case I convert to seconds.

Hey, as long as you get the calculations right, you can use whatever units you like. Google says (10,000 yards) / (30 minutes) = 30,545.4545 furlongs per fortnight.

Originally Posted by I'm goin' down

razark, I did not know changing headings might affect the radar range and bearing readings adversely. If it is true, it is a good think to know. You might as well take the first reading when you are pointed at the target, otherwise you may have reading that are accurate but you could be getting further away from it.

Well, if you are trying to get a correct bearing on the target, and you're turning, holding the radar on it would be a bit tougher. The bearing you are trying to read would be constantly changing, and holding the beam to get the range would be a challenge.

[razark]

Originally Posted by razark

Like I said, my bearings have been 7 degrees off. To port. Rather consistently. If had a target at 000, I'd get a bearing of 353.

Trying again today. What I'm seeing against stationary targets is that I sweep the beam across the target. Once it's past the target (no blip on the A-scope), I crank it back counter-clockwise, until it shows up again. I then use the mouse scroll wheel to advance the beam clockwise two clicks. My bearings have been dead on. I don't know if this specific measurement is affected by range, but it was consistent with three separate targets.

Back to the radar training grounds.

[I'm goin' down]

143 kts for a merdchant. Not bad IGD!!

You had a better point than I though. If the target is moving away, get ahead of it. Then you can reduce speed, per Channings post and plot the "x" close the boat. I needed some good advice. That was good!

[I'm goin' down]

I am going to wait for the tutorial before I continue using the mod. I have put in enough time to determine it will be difficult to use. If you have a contact at long range, it is difficult to plot the correct bearing because the screen is not large enough to accommodate detail over long distance, say 25,000 yds. The angle created by the protractor tool is too small to see and this fact and the length of the range line, make it difficult plot the bearing and range of the target, among all of the other issues I have raised. Now, If I were playing on my big screen TV....

[John Channing]

The size of the screen is alway going to be a problem. I can never seem to get just the right zoom level to get it perfect.

But remember, at ranges of 20 Kyds or greater you don't have to be spot on the money accurate. Initially all you need to do is establish his approximate track. Once you have that down you can begin to close his position and take your time refining your plot. Once all of that adds up you will enter the solution.

It's frustrating at first because you are actually doing the work of 5-7 people (the radar operator, the approach officer, the TDC operator, the plot team and the Captain) but once you get it down it is most rewarding.

JCC

ps. Almost done. Just have to check a couple of details with Nisgeis and fix a couple of miistakes. It's a long one, so thanks for you patience.

[irish1958]

Originally Posted by razark

Hey, as long as you get the calculations right, you can use whatever units you like. Google says (10,000 yards) / (30 minutes) = 30,545.4545 furlongs per fortnight.

GREAT; this is the missing link for manual targeting

[Nisgeis]

Originally Posted by irish1958

GREAT; this is the missing link for manual targeting

Don't forget the other essential bits of info:

Range: 3.868734e-12 light years
Course: π/4 radians

[razark]

Originally Posted by Nisgeis

Don't forget the other essential bits of info:

Range: 3.868734e-12 light years
Course: π/4 radians

When the trig teacher said I'd be using this stuff later in life, this isn't what I expected!

[sergei]

Some Feedback:

Loaded up a single mission (TMO+RSRD) that had me patrolling just south of the Bungo Suido in late '42.

Target 1:


My initial 5 marks showed him going vaguely SSE, but I wasn't sure if maybe he'd made a turn at some point or was zig-zagging.
I put it down to inaccurate plotting on my part.
After I had marked points 6-9 I had a very good idea of his course. Obviously points 2 and 4 were aberrations. Possibly due to me not holding the beam on the target accurately.
I have worked out that at 30,000 yards a variance of 3 degrees gives you a possible error of 1700 yards!
So, obviously at long range you are just trying to get a sense of the targets general direction of travel.
As the range drops it becomes easier to get accurate plots and possible bearing errors have much less of an effect.
As the range dropped you can see my marks becoming a lot more consistent.
You can see the second plot I started when the target was close enough for me to get accurate stadimeter readings. It's pretty damn close to my radar plot.
And I sank the bugger right in the middle of my two plots.
Very satisfying.

Target 2:


I can see a pattern developing here
Again marks 1 to 5 are not consistent enough to give the targets true course yet, but they are good enough for me to decide which direction I need to head for the intercept.
As the range dropped I decided that marks 8-10 were probably close enough, so that's what I predicted his course as with the ruler.
As he got into visual range I would take occasional stadimeter readings just to check that he was still on the course I had predicted. I measured these, but as they showed him still on track I did not bother marking them.
In this attack I noted the time of my initial contact was 3.55am.
I made a visual mark exactly one hour later at 4.55am (not shown, I accidentally deleted it whilst deleting all my ruler marks and range circles ).
The distance between that mark and my first was 10.2 miles (IIRC) so I used 10 knots as his speed.
Worked like a charm.
You can see where I got him, very close to my predicted track.

I am very much loving this mod

Once I was close enough to get a stad reading I activated the PK and would watch the attack develop on the TDC (occasionally taking another range reading to keep it updated). It gave me a real good feeling for what was going on. Looking forward to JC's tutorial so I know what most of the dials are for

A thought: whilst switching off the radar between readings may make it easier to use because it remembers your last range and bearing, doesn't that also switch off your air search radar? Or is it always on regardless of the state of your surface search radar?

A question: my Gato had listed in the equipment screen an early SJ radar with a range of 20,000 yards. However, I was getting contact out to about 40,000. Is that to do with this mod, or have I FUBARED my game again?

[I'm goin' down]

very nice demonstration w/screenshot. where was your boat during all of this. Was the target closing, etc.?

[sergei]

Originally Posted by I'm goin' down

where was your boat during all of this. Was the target closing, etc.?

Target 1 was heading pretty much straight for me, so I ended up going straight up his track, then moving about 1500 yards off his track just as he came into visual range (spotted by my crew at about 8,000 yards IIRC. It was a clear night)


For target 2 I was in a much less favourable position.
A bit further south than you can see on this map


But I could tell from my initial marks that he was heading vaguely East, or maybe ENE, so I knew I had to head north for my intercept. I stood on the gas for part of the attack, to make sure I got there in plenty of time.

[I'm goin' down]

I attacked an Akita Maru with map contacts on, but I plotted the readings. I have given up on manual speed calcs. I used the TDC for that. However the TDC course determinations were inaccurate. To make a long story short, the target course I plotted with your mod was solid. I lined up for a broadside, the target was doing 10 knots, and I set the firing point for 350 degrees. But, I must be getting senile, as I fired when the target crossed the 340 degree bearing and all the shots missed.

However, I did learn some tricks. First, it is easier to plot if the target is heading your way. Second, since the sub is moving, it is better to slow down to 1/3 or 2/3 standard when you take readings. When you plot the readings, the angle of the protractor will be more accurate than if the sub were proceeding at standard speed or faster. Third, as the target gets closer, you can sometimes get a good range reading off the PPI scope even with the dial on underneath the radar screen turned all the way to the left.