Help with RAOBF dis. My measurements are off.

[Compans57]

I'm using real navigation and trying to get a handle on the RAOBF disc, but my findings are consistently about 1500m to 2000m off. I've followed video and pictorial tutorials so I can't figure out what I'm doing wrong.

For example, I had a Nelson class battleship at 2 optics mast height. Actual mast height is 55m. This reads off as (IIRC) 8500m but (I'm testing results with map icons) when I use the map ruler the actual range is around 7000m.

Are there different optic graphics? I realize that optic height can be out due to waterline but not this much.

Anyone have any solutions?

[3catcircus]

The difficulty is in the fact that the graticules are not centered, which makes it very difficult to confirm the actual number of ticks. You might be at 2.2, or 1.9, or some other not exactly 2.

I'd work backwards. Get range on the map, dial it in to the mast height, and see how many ticks are shown at the hash mark. If it is slightly different than the 2 you've indicated, then you're just not being precise enough. If it is vastly different, it could be that you need to select a different multiplier or hash position on the disk for the magnification you are using.

That having been said, I've not seen *any* correct implementation of the RAOBF beyond karamazov's initial implementation up to and including Makman's. Everything after that seems to be off.

I've had problems moreso with determining AOB - the value dialed in and known to be good because I checked before hand with the map tools, doesn't match the value that shows up in the scratchpad.

[Compans57]

The difficulty is in the fact that the graticules are not centered, which makes it very difficult to confirm the actual number of ticks. You might be at 2.2, or 1.9, or some other not exactly 2.

I'd work backwards. Get range on the map, dial it in to the mast height, and see how many ticks are shown at the hash mark. If it is slightly different than the 2 you've indicated, then you're just not being precise enough. If it is vastly different, it could be that you need to select a different multiplier or hash position on the disk for the magnification you are using.

That having been said, I've not seen *any* correct implementation of the RAOBF beyond karamazov's initial implementation up to and including Makman's. Everything after that seems to be off.

I've had problems moreso with determining AOB - the value dialed in and known to be good because I checked before hand with the map tools, doesn't match the value that shows up in the scratchpad.

Thanks mate. Could it be the magnification on the attack periscope? I seem to just have two magnifications - zoom in and out. I'm not sure of the power of this, ie 6X or 1.5 but I imagine that would affect things.

[Compans57]

Following your advice I find that if the contact is far off and fairly small in the scope, an addition of .5 of an optic height works. If the target is large in the scope an addition of 1 optic works.

For example: if the optic height in the scope is 2.5 and the ship is far away, I make the reading 3. This however is incredibly unscientific. Do other people have these problems? Range is not too important as regards torpedoes unless the range is beyond the capabilities of the torpedo. It's quite another matter with fats, as setting when the leg starts is vital.

Mt stadimeter readings seem way off as well.

Another question is when measuring mast height with ships that have a mast coming from the bridge, do you take this mast as the measurement or one of the ones on deck?

[3catcircus]

Typically the intent is to measure from waterline to the tallest mast.

Although range isn't that vital, a good range is needed to then determine AOB using the RAOBF.

[bstanko6]

I never zoom in when calculating with RAOBF. There are tick marks that allow you to use the zoom, but it complicates things.

[3catcircus]

I never zoom in when calculating with RAOBF. There are tick marks that allow you to use the zoom, but it complicates things.

The problem is, for us old guys, the Mark 1 Eyeball has some difficulty with the 1.5x in seeing sufficient detail.

For me, it would be a lot easier (in any of them: SH3, SH4, and SH5) to have the graticules centered rather than offset - most mods don't allow you to move the scope or the raobf dial while paused to get an accurate count of the tick marks, so if stabilization isn't on, it becomes very difficult - almost to the point that guesstimating based upon image size and experience is just as accurate.

[Compans57]

The thing is, from the video tutorials I’ve watched I assumed they were zoomed in too. Otherwise you’re limited to finding range when the contact is right on top of you. I prefer to attack from very long range, especially after 1942 when the escort presence is heavy - 8k to 10k.

[3catcircus]

The thing is, from the video tutorials I’ve watched I assumed they were zoomed in too. Otherwise you’re limited to finding range when the contact is right on top of you. I prefer to attack from very long range, especially after 1942 when the escort presence is heavy - 8k to 10k.

It doesn't even need to be very long range. The images size is tiny up until you're just under 5,000 m or so. At that point you really have no ability to maneuver since you should be submerged already.

[Compans57]

I've been continuing to investigate this and it doesn't make much sense. My question is have other people checked the measurements on RAOBF with the map tools? Why are my findings so off? I've double, and triple checked everything.

I've found that if the target is fairly close, I can get accurate results if I subtract 500 metres. ie - 2500 metres on the RAOBF is actually 2000 metres. But at longer ranges it gets completely out of whack. 2000 metres and more off.

Could mast heights be wrong, either in the 3D models or documentation in SOANS?

I'm genuinely interested to see if others have tested this.

[derstosstrupp]

I've been continuing to investigate this and it doesn't make much sense. My question is have other people checked the measurements on RAOBF with the map tools? Why are my findings so off? I've double, and triple checked everything.

I've found that if the target is fairly close, I can get accurate results if I subtract 500 metres. ie - 2500 metres on the RAOBF is actually 2000 metres. But at longer ranges it gets completely out of whack. 2000 metres and more off.

Could mast heights be wrong, either in the 3D models or documentation in SOANS?

I'm genuinely interested to see if others have tested this.

Please post some screenshots with information on the ship in the scope, and then we can get to the bottom of this.

In the meantime though, I only use the centiradian marks in the scope, because I normally shoot at such low gyro angles that range doesn’t matter. I would suggest you do the same. RAOBF is a handy tool, but there was a reason why they dispensed with it (as well as the split-prism stadimeter) on scopes after 1939 (namely on the C/2 Stand-Sehrohr attack scope you see in game in the tower), because mast heights were seldom known or relied on, nor was that information really needed when in practice they minimized their gyro angles making range have no impact on the lead angle.

[Compans57]

Please post some screenshots with information on the ship in the scope, and then we can get to the bottom of this.

In the meantime though, I only use the centiradian marks in the scope, because I normally shoot at such low gyro angles that range doesn’t matter. I would suggest you do the same. RAOBF is a handy tool, but there was a reason why they dispensed with it (as well as the split-prism stadimeter) on scopes after 1939 (namely on the C/2 Stand-Sehrohr attack scope you see in game in the tower), because mast heights were seldom known or relied on, nor was that information really needed when in practice they minimized their gyro angles making range have no impact on the lead angle.

Thanks I’ll take some shots. I agree with gyro angles and I use fixed wire attack. The thing is it does matter with fat torps. Also, other than using WEPS or Obs officer, there is no way of getting range during pursuit phase or when spotting a ship in the distance.

[les green01]

range even with fat was a estimate unless they was using radar longer the range less loops it will make and the newest TWoS update you can't preheat the g7e so the range is even shorten

[Compans57]

range even with fat was a estimate unless they was using radar longer the range less loops it will make and the newest TWoS update you can't preheat the g7e so the range is even shorten

The problem is with sticking to strict historical comparisons is that this is a game. It's very hard to tell sometimes in SH5, which ship is in front of the other for example. As we don't have any peripheral vision (which is essential for judging far away objects) in the game we're forced to compromise.

[Able72]

I'm using real navigation and trying to get a handle on the RAOBF disc, but my findings are consistently about 1500m to 2000m off. I've followed video and pictorial tutorials so I can't figure out what I'm doing wrong.

For example, I had a Nelson class battleship at 2 optics mast height. Actual mast height is 55m. This reads off as (IIRC) 8500m but (I'm testing results with map icons) when I use the map ruler the actual range is around 7000m.

Are there different optic graphics? I realize that optic height can be out due to waterline but not this much.

Anyone have any solutions?


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.

[Alpheratz]

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]

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.

[Alpheratz]

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:



https://i.imgur.com/FVg6bIC.png

[nazaka]

image of the length measurement X1.5:



https://i.imgur.com/nTPg9PT.png

[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/1aJD4qpS8BMeY-3x8hc6lw5XH_-oS4FZl/view?usp=sharing

[Able72]

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/1aJD4qpS8BMeY-3x8hc6lw5XH_-oS4FZl/view?usp=sharing


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

[Alpheratz]

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/11PQDAWOvb0_z_qC46TlXm0_QQDI5PkcI/view?usp=sharing

[Alpheratz]

This is how it works for me.

https://i.postimg.cc/Gm95DLC0/centi.png (https://postimages.org/)

https://i.postimg.cc/NfdnLyZ7/mast-1.png (https://postimg.cc/w7s2GBq7)

https://i.postimg.cc/FzDTfqCs/Mast-2.png (https://postimg.cc/vxxrkPdp)

[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]

This is how it works for me.

https://i.postimg.cc/Gm95DLC0/centi.png (https://postimages.org/)

https://i.postimg.cc/NfdnLyZ7/mast-1.png (https://postimg.cc/w7s2GBq7)

https://i.postimg.cc/FzDTfqCs/Mast-2.png (https://postimg.cc/vxxrkPdp)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.

[Alpheratz]

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.

https://i.postimg.cc/7L63g0b1/Lighthouse-Narvik.png (https://postimg.cc/VJx0wSq5)

https://i.postimg.cc/9Q1PRJXF/Lighthouse-Narvik-x1-5.png (https://postimg.cc/rD0R7Gtv)

https://i.postimg.cc/02Y0x9LS/Lighthouse-Narvik-x6.png (https://postimg.cc/D8zXP3ff)