RFB, Accurate Manual Targeting and Realism

[jazzabilly]

That's why I have a post-it note slapped to my computer monitor that reads:

Merch's: top of the tallest mast
w/ships: top of the tallest funnel
cv's/cve's: flight deck.

I'm hitting 'em, I just ain't sinkin' em....working on selective targeting skills....

[Paul Roberts]

So, just to be clear: for warships, the "mast height" listed in the Recognition Manual is not really the height of the mast, but rather a number worked out so that placing the Stad line on the tallest funnel will calculate the target's correct range?

[Donner]

Originally Posted by Paul Roberts

So, just to be clear: for warships, the "mast height" listed in the Recognition Manual is not really the height of the mast, but rather a number worked out so that placing the Stad line on the tallest funnel will calculate the target's correct range?

Correct. Some of the info is off in the RFB manual by design. I know of at least one warship in particular that doesn't follow the 'distance reference point' outline above. But by using sonar and/or radar, you can establish the proper reference point for stadimeter range.

I know it works because I have bagged this particular ship several times!

[CapnScurvy]

Originally Posted by Rockin Robbins

If even CapnScurvy is getting confused about how RFB works, maybe it would be better to rethink the whole process

Yep, my mistake to lead anyone down the wrong path. Lash me to the yard arm Double R, I feel a whoopin' is in order. I must be feeling full of piss and vinegar today to start this.

Donner, your exactly right. With manual targeting you can still get an accurate range by using the sonar to "send" the found range to the TDC (Position Keeper). Don't let your sonar man do it for you though, go find the range yourself, then send it along. Those boys aren't to accurate, to much gazing at the wall hangings down there in the sonar room. Just don't ping away without figuring on an escort to not come looking for you in a trot.

[E.B. Fluckey]

For this reason (and the lock issue) I uninstalled RFB and installed TMO and SCAF. Manual targetting is a joy now. I tried installing SCAF and RFB without luck.

So until this is fixed I'm sticking with TMO, RSRD, and SCAF configuration. This works really well.

[tater]

That's great except for the fact that Real skippers had ONI, not superdetail models researched by japanese guys.

In other words, they GUESSED.

Read Alden's book. COmpare US skipper CLAIMS of ships sunk to what they actually sunk. 8000 ton CA? No, Akizuki DD. ONI? 120' mast height for the claimed CA, 75' mast height for "Unknown" Class DD.

That's not 1 meter off, it's 13.7m off---none the less, the target ended up on the seabed.

For merchants, we have ~16 in SH4. With the exception of the late war "standard types" (not yet in game), it was rare for more than 10 to be in any given class. Instead of 16 targets, we should have HUNDREDS. This is in sharp contrast to the ATO where the US built so many standard types that they literally became the majority of shipping seen. Add to that that much of the data for these hundreds of slightly different targets is not rated "A," but a lower B or C in intel quality, and the mast hieght becomes a GUESS. You eyeball a deck height, then have the periscope assistant set the height at 100' or whatever.

Given this guess work, a few meters off in mast height would be EXCELLENT estimation in RL.

To sum up:

In RL, they set the stadimeter to a height in feet.

They got this figure from either ONI (41-42, 208J, etc), or by guestimating it based on features they could make out.

In the latter case, their guestimate had to do with how big they thought she was. I've gone through Alden putting stats in a spreadsheet, guess what, they almost universally overestimated target size. In many cases, considerably. That means they almost universally overestimated mast height.

[tater]

Sorry, edit no worky.

I pulled the wrong ONI page. UK DD 75', claimed CL, 90'

4.57m difference, not the 13 I said above. Mea culpa.

[sckallst]

Well, reality in any of this is hard to come by once you come to grips with the fact that no matter what in-game command decisions you make, you can always exit to Windows and reload without worry of dying. I think RFB does a pretty decent job of levelling the playing field despite it all.

That said, I think one point to be made is that if getting a good range on a target is a problem such that increased range will introduce increased error of an unacceptible degree into the firing solution, one obvious solution to the problem is to get closer to the target. If you can't you have a tougher decision to make. I think that is pretty realistic.

Active sonar, when safely available in a tactical situation, even if depending on the operators and not using a DIY approach, can be used in tandem with your stad readings. Get a few readings, set the PK in action, then ping once after a minute or two and check the report against the PK. Once you get radar on your boat, there is a good chance that if you've got it all plotted right and you plan on using the PK, you'll know if your stad reading is right as soon as you take it. There is even a good chance you will be able to manually target without the TDC using your radar-generated /passive sonar-verified plot without even coming up to look if . For further realism, keep a patrol log and document your experiences and findings as you go. That's how real intel is gathered. You'll know from experience when to take extra steps to verify range to target.

Another solution is to use largely range-irrelevant firing solutions, such as vector analysis methods. Get yourself on a converging course, and or two decent though not exact range estimates, along with an anayisis of the rate of bearing change can give you pretty much all the info you need to set up a decent spread.

Which brings me to another point: In game most of us fire spreads so that when it all comes together we get three or four perfectly placed holes in the target. I think most skippers in most situations fired spreads hoping that one or two of the fish might find the target given the uncertain nature of the data used to compute a solution.

Finally, most of us bag more targets in a couple of patrols than many boats fired at for the duration of the war. If we miss a few because of uncertain data (that problem being not unrealistic at all), I can live with that in the name of realism.

Not banging on anyone, as given the first point 'realism' is a pretty hard target to range, and we all try to get that 'enjoyment' out of it which is satisfiying to each of us. Just offering a different perspective on some of these range 'realism' issues.

[Rockin Robbins]

Originally Posted by E.B. Fluckey

For this reason (and the lock issue) I uninstalled RFB and installed TMO and SCAF. Manual targetting is a joy now. I tried installing SCAF and RFB without luck.

So until this is fixed I'm sticking with TMO, RSRD, and SCAF configuration. This works really well.

But has it occurred to you that manual targeting is not supposed to be a joy? It is supposed to be realistic, and that means that you are guessing a lot and much of your information is just plain wrong or misleading. Watch TMO move in this direction. Your joy is to be short-lived. Muahahahahahaha!!!!:rotfl:

[Rockin Robbins]

Originally Posted by CapnScurvy

Yep, my mistake to lead anyone down the wrong path. Lash me to the yard arm Double R, I feel a whoopin' is in order. I must be feeling full of piss and vinegar today to start this.

Except that in this case, Capn, I'm not whoopin' on you. I'm using you as the supreme example of someone who is incredibly familiar with manual targeting, but was confused by the RFB stadimeter procedure. I'm suggesting that shows RFB needs to think about returning to a single standard for all targets.

Here's the question for you. If the top of the tallest stack is half the height of the tallest mast (probably it is more like 2/3), doesn't that have implications for the range accuracy? For instance, if at 1000 yards a one pixel error made a 50 yard error in range at the masthead, wouldn't that be proportionally greater for the lower elevation of the tallest stack, yielding a range error of 75 to 100 yards with the same one pixel measurement error? There doesn't seem to be a free lunch anywhere around here.

[CapnScurvy]

Originally Posted by Rockin Robbins

Here's the question for you. If the top of the tallest stack is half the height of the tallest mast (probably it is more like 2/3), doesn't that have implications for the range accuracy? For instance, if at 1000 yards a one pixel error made a 50 yard error in range at the masthead, wouldn't that be proportionally greater for the lower elevation of the tallest stack, yielding a range error of 75 to 100 yards with the same one pixel measurement error? There doesn't seem to be a free lunch anywhere around here.

Boy-O-boy Rockin R, I had to read this question a time or two to understand what your asking. For a minute I was picturing a similar question "If Tom leaves his house and heads west for 22 minutes at a speed of 15 mph, and Fred leaves his house and heads east....................." then I snapped out of it!!

Yes, there are implications for range accuracy. There are a couple of factors that make the difference. One is the height in the periscope image when the Stadimeter is being used. The higher up from the water line the stadimeter second image is placed, the less difference in range there will be. The game was developed with this in mind to simulate a target farther away will appear smaller in the scope image. This is to make it more difficult to get a correct range when the target is farther away. When the target is nearer, it fills up more of the screen, and the difference in one pixel line to another is less when making a stadimeter reading.

The second factor is the actual Mast Height figure (from this point on I'm going to just call it height, it really doesn't need to be the mast at all). I found that differences in adjacent pixel lines were made do to the size of the height measurement. The larger height measurement created less range difference between adjacent pixel lines. The smaller the measurement the greater the difference. I believe the devs did this to balance out the playing field, to make each ship as equal in range finding, even though on ship is small the other is large.

So the truth is there is almost a wash between the two factors, one balances out the other. Here's an image of what I'm talking about, just read the green highlights for now.



This image displays the first factor I mentioned, the stadimeter placement within the scope image. The differences are gradual from the waterline to the top. So don't misunderstand my poor drawings, thinking the pixel line differences only occur within the green marks.

An example for the second factor, the height measurement. A figure of 10 meters could produce a difference of 6 meters to 1 meter difference between adjacent pixel lines. The 6 was toward the waterline, the 1 towards the top of the above image. For a height measurement of 25 meters, the differences were doubled. The lower towards the waterline you would get 12 meters range differences between pixel lines, the higher you would get 2 meters difference.

You may wonder where these points were taken. Although RFB did away with the horizontal center line, there are three larger hash marks above the center of the scope. I used those three hash marks to check the differences within the scope image. Believe me, the closer to the water line you get the much larger the difference becomes. The differences of 6 meters or 12 jump real quick as you lower the stadimeter mark point.

I'm going to kill two birds with one stone so I have a reason to point out the red marks on the first image. You'll notice the Base Height is set to the RFB figure of 16.5 meters. I had just completed a range check and the PK shows the found manual range as 2605 meters. That's all fine and good except the actual range to target was 1748 meters!! That's an 857 meter difference off target. Did I say you couldn't hit a bull in the as.................... Yep, I did. And no you couldn't!! Oh yea, if you would shoot at point blank range, but I don't want to kiss 'em.

The following image shows the corrected height as 11.1 meters. The PK now shows a found range to target of 1757 meters, just 9 meters off. Anything under 15+/- meters off, is right on target, the game really won't calculate it any closer.






I thought I'd show you what one adjacent pixel line will do when using the same corrected height.






Can you see the difference in the position of the stadimeter waterline mark? That's one pixel line. I mentioned the horiziontal hash marks on the scope, there are 3 pixel lines to the thickness of one hash mark line.

A 43 meter difference with a height measurement of 11 meters over a distance of a little over 1700 meters. I know you guys think that height measurements shouldn't be dead on, because this gives us too much accuracy, but for a long time I've known there isn't any way fool proof range finding will occur. Can you see what a difference would be if the seas were rough, it's dark, you have an escort breathing down your neck, you miss the speed by a knot, or the AoB is off a bit. Good height measurements do not guarantee a thing.

And one last thing, if RFB uses official documents like the OMI to input base height measurements in game, why is the Bogue American Carrier not correct? We don't know what our own ships heights are? And don't feed me some line of bull about real life would have given false information to the enemy as standard practice!!

A couple of other range inaccuracies in an approximate distance of 1700 meters.

Victory Freighter was off 95 meters too long

Fletcher DD 138 meters off target too short

Somers DD off 91 meters too long

Wasp CV off 152 meters too long

River Class off 281 meters too short

Hogs Island Freighter off 213 meters too long


OK, long enough for now.
VANJEST, YOUR TIMES COMING. I GOT A RESPONCE FOR YOU 'OL BUDDY. :rotfl:

[tater]

What difference would a US CVE make, who'd shoot at her? If it was a u-boat, you'd need to know what height the germans thought she had. I've never looked at the US ships at all, myself (they ain't targets).

When Shinano was attacked, they had no idea how big—or tall—she was. The skipper made some observations, perhaps assumed the island was XX feet tall, then set up the shot.

I agree that you should have a fairly accurate range under the assumption that the skipper has the actual height of the target. In RL, this was simply not the case. GIGO.

ONI has Shokaku's deck as ~50' above the waterline with a 21' draught. More accurate sources have ~56' for the deck, with a 29' draught. That's ~2m difference, and assumes an average draught. If the ship wasn't at that load (which is a special case) the deck height could be off by another couple meters easily.

So again, in RL, you'd pretty much be guaranteed to never have the right height data from your rec manual. For virtually every single attack, if you wanted an accurate range, you'd need to make estimates yourself about the target's height. Have to.

Fully loaded? Overloaded? High in the water (unloaded)? Ship look the same as pre-war images (some perhaps 10+ years old)? The ship's draught being spot on is a special case. If they use an average, half the time it should be lower (a few meters, perhaps), half higher. Virtually never the average itself.

ONI serves as a reference, then you adjust the height based on what you see.

So, under the assumption that as skipper you either perfectly estimate the height, or you have that rare target where the height you get from a rec manual is 100% accurate, then yeah, the error should be as small as the game allows.

[Paul Roberts]

Originally Posted by jazzabilly

That's why I have a post-it note slapped to my computer monitor that reads:

Merch's: top of the tallest mast
w/ships: top of the tallest funnel
cv's/cve's: flight deck.

I'm hitting 'em, I just ain't sinkin' em....working on selective targeting skills....

I think RFB is set up so that precisely this reminder pops up when you hover the mouse over the Recognition Manual check box.

[Rockin Robbins]

If even CapnScurvy is getting confused about how RFB works, maybe it would be better to rethink the whole process. I wonder if it's not just too confusing to have many different height references depending on what kind of target. Why not make the top of the highest stack standard for all?

On the other hand, in real life they checked out the ONI manual and used the reference of their choice. The reason we are disposed toward the mast height is that the taller the reference point the more accurate the range measurement. If we accurately know the real height of the mast...

[CapnScurvy]

So here are some Warships funnel heights. Stock figures are removed since it doesn't offer anything other than the tallest mast height.

Asashio DD
RFB=12.192 at funnel
Accurate=11.5

Minekaze DD
RFB=10.2108
Accurate=11.2

Kuma CL
RFB=14.6304
Accurate=17.4

Fubuki DD
RFB=14.0208
Accurate=13.2

Shiratsuyu DD
RFB=13.1064
Accurate=9.6

Deck Heights

Taiyo CVE
RFB=13.716 at deck
Accurate=15.29

Casablanca CVE
RFB=12.4968
Accurate=13.9

Bougue CVE
RFB=16.4592
Accurate=11.3

As I've stated before, at an average distance of 1200 yards, 1 meter difference in height will produce about 50 yards difference in range. The further away you are the greater the inaccuracy. This occurs no matter where you place the Stadimeter as long as it relates to the correct spot the Ship_Name.cfg mast height figure is calculated for.

Originally Posted by Paul Roberts

So, just to be clear: for warships, the "mast height" listed in the Recognition Manual is not really the height of the mast, but rather a number worked out so that placing the Stad line on the tallest funnel will calculate the target's correct range?

Yes, that's right. As long as the "mast height" figure in the "ship_name.cfg" file relates to a spot on the ship that is calculated for accuracy the position that you place the Stadimeter must use that spot for accurate range finding. Unfortunately, the game only recognizes one spot.