Help with RAOBF dis. My measurements are off.

Originally Posted by Able72

I'm having the same issue, but worse. Even paused and counting tick marks comparing it to the map distance, I'm coming up sometimes more than 1100m off of range. This makes AOB using the RAOBF way off. I remember using the original RAOBF with SH3 and it was a fantastically accurate tool. Perhaps, just my thoughts, we need to have someone take the time to rescale the reticle markers and replace the default ones in TWOS. Perhaps over time the scale has gotten off and a correction is needed.

The problem might be that your monitor is not 16x9. At one time, I solved this problem by activating TWoS Aspect Ratio Fix 5x4 in JSGME. Since then, RAOBF has been working fine with my 5x4 monitor. This also works fine with TWoS 2.2.24 for me.

[Able72]

Originally Posted by Alpheratz

The problem might be that your monitor is not 16x9. At one time, I solved this problem by activating TWoS Aspect Ratio Fix 5x4 in JSGME. Since then, RAOBF has been working fine with my 5x4 monitor. This also works fine with TWoS 2.2.24 for me.

Nope. My monitor is 2560x1440. That's 16:9.

By the way, the tops of the masts of some ships are especially thin and they just don't render at a great distance. They "suddenly appear" only at a distance of about 2000 m and closer. Measuring the distance over 2000 m to these ships, you will get an overestimated result for this reason.

[JerseySeven]

As Alpheratz said, pixel resolution, time of day, weather, all make it difficult to see mast height at longer ranges. It's why I like to check the range one last time shortly before firing.

[nazaka]

The main source of error between the measured distance and the actual distance of the target vessel is the inaccuracy of the mast heights.
Same for the AOB measurement, the lengths are sometimes very far from reality.

To verify this, I did a very simple test to get the real values of the ships: ships located at key sites (0-45-90-135-180-225-270-315), at a distance of 1000m and with an exact AOB angle of 90°.

And I checked the really interesting ships. And I got some surprises.

A nice example was the DALE:
_ on the identification booklet it was indicated: length(139.6m), mast height(29.7)
_ during my test: measured ship length (17.9 ticks, or 179m) and measured height (10.9 ticks or 27.2m)

Difficult to have measurements close to the real with so many differences.

[nazaka]

image of the mast height measurement in X6:

[nazaka]

image of the length measurement X1.5:

Due to the fact that the IRL could not talk about the mathematical accuracy of determining the range to the target, the comment by derstosstrupp is exhaustive on this topic IMO. You can try the table for determining the range with the centiradian scale:

https://drive.google.com/file/d/1aJD...ew?usp=sharing

[Able72]

Originally Posted by Alpheratz

Due to the fact that the IRL could not talk about the mathematical accuracy of determining the range to the target, the comment by derstosstrupp is exhaustive on this topic IMO. You can try the table for determining the range with the centiradian scale:

https://drive.google.com/file/d/1aJD...ew?usp=sharing

I"m sorry, I don't read or understand German. I can't make any sense of this table. Can you help?

Originally Posted by Able72

I"m sorry, I don't read or understand German. I can't make any sense of this table. Can you help?

I have translated this table for you:

https://drive.google.com/file/d/11PQ...ew?usp=sharing

This is how it works for me.

[nazaka]

Try doing the same thing with a Large Liner.

You'll never get the measurement right, even with your method.
The mast is off by almost 4m.

[Pisces]

Originally Posted by Alpheratz

This is how it works for me.

Are you sure you are interpreting the scale correct? Remove the recognition manual. Is there another marking "10" on the opposite side of the horizontal centerline? Or does the scale start counting from the bottom?

[Markus Witt]

Alpheratz calculation is correct. Personally I always have a sliderule standby for quick and easy range calculations. In this example I get a range of 2850 meters, see attached. Sliderule is also handy to calculate in advance the number of crads you need if you want to fire at a certain range.

In this example actual range is (29.9) / (4.2 / 4) = 2848 m.

Originally Posted by Pisces

Are you sure you are interpreting the scale correct? Remove the recognition manual. Is there another marking "10" on the opposite side of the horizontal centerline? Or does the scale start counting from the bottom?

Yes, I am sure. I checked the graduation of the radian scale on lighthouses as well. Previously, I carefully determined the height (70m) and the location of the lighthouses using RAOBF before posting the tutorial video (SH5 School of Navigation. Level 1). I also tested my centiradian table on 5 types of ships: only in one case, probably due to an incorrect mast height in the recognition manual, there were erroneous readings. In all other cases, the readings are consistent with each other and with the RAOBF results. Here's an example with a lighthouse. U-boat is located in Narvik at a distance of 1000 meters from the lighthouse.