Omnimeter -- Historically accurate and was it used in WW2? That is the question.

[I'm goin' down]

I have been exchanging PMs with Rockin Robbins and CaptnScurvy re the use of the Omnimeter, developed for game play by CaptnScurvy. Their is disagreement as to whether the Omnimeter shown in the Navy's Submarine Fire Control Manual is really an Omnimeter, and if it is (which I believe it is), whether the Navy used it. Maybe this thread will generate some more information on the subject, or maybe, just maybe, it will generate one of our interesting lovefests. Here are the PM exchanges with Rockin Robbins, and PMs to me from CapnScurvy, who reviewed and commented on the exchanges (with minor, insignificant editing on my part.) Comments are invited if they can help resolve this issue. Since I was dealing with PMs from different captains, I copied them to Microsoft Word, and then block and copied them to this post.

Originally Posted by I'm goin' down in PM to Rockin Robbins dated October 4, 2011

You ought to try the OTC mod with American radar from the beginning of the War. Turn map contacts off. It is quite a game. If you add Toyyko's revenge, forget your summer vacation. Where the heck have you been by the way?

Rockin Robbins reply to PM

The problem with Scurvy's stuff is that it works too well. It's god mode, where every ship on the ocean is known with perfect accuracy and makes contacts off just as much a mixed bag of knowing too much as map contacts on with TMO. He's made manual targeting into a perfect system without error and that just isn't anywhere near accurate. I like Ducimus' treatment of the game much better, so long as you have a boat with radar. Then the real sub would have even more accurate data than you have plotted.

The problems with the ship database are different from the problems the real skippers had, but the effect is the same: misses with normal manual targeting practice where you have to identify the target. That drives Scurvy crazy.

I'll load it up for a mission or two, but I doubt I'll be running a campaign with OTC. I don't know a thing about Tokyo's Revenge. I'll have to check that one out.

*****
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Rockin Robbins supplemental reply to PM

Where in the WORLD did Scurvy come up with this "Omnimeter?" There was no such thing in WWII, we didn't know the lengths of the ships and we sure didn't know their masthead heights. Yet, using all this information that we never had and inventing an "Omnimeter" out of thin air, he claims to make the game more authentic? This is madness...
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I"m goin' down's response to Rockin Robbins PMs:

I believe you are mistaken. There was such a thing. How much it was used or whether it was ever used in combat, I cannot answer. I will lead you through it.

This link should take you to the post where the omnimeter is discussed. http://174.123.69.202/~subsimc/radioroom/showpost.php?p=1397786&postcount=1

Post no. 30 in the thread is authored by CapnScurvy. It contains a link to the Submarijne Fire Controll Manual. The Omnimeter is referred to specifically in at page 5-3 and is referenced indirectly on page 5-4 (The reference to Plate III on both pages refers to a picture at the end of the manual. The picture is of the Omnimeter.)

I am not in position to debate you on whether the tool was used. It was available for use it appears. Whether its use was feasible is not is something I am in a position to argue (if you say that the U.S. did not know the target lengths or heights, that is good enough for me), but I don't particulary care. Using the Omnimeter with real scopes (part of the Omnimeter download) is not easy, especially at night, but it is a cool tool, and CapnScurvy has spent a long time ensuring it measures ranges, properly taken, accurately. Plus, the Omnimeter is easier to use than the 3D TDC and Radar Range Unit (I saw one of those during the movie Run Silent Run Deep!)l, which has too many steps for me to follow.

If you install the option of U.S. radar from the beginning of the war, you can see planes on radar when they are within range, and track ships too. Add Toykko's revenge, and you will have your hands full.

I am copying CapnScury, as he may be able to add some information.

Let me know what you think.
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I'm goin' down's supplemental PM to Rockin Robbins and CaptnScurvy:

Here is the link to the thread rather than to the first post. [/url]http://174.123.69.202/~subsimc/radio...86#post1397786

I'm goin down's second supplemental PM to Rockin Robbins and CapnScurvy:

Well, here is what the manual says. It sounds like an omnimeter, and it provides a method counting the height of ship by counting the telemeter marks. CapnScurvy's tutorial discusses using the telemeter marks to determine mast height. The Navy may not have used it in the war, but the concept is clearly discussed in the manual.

500. THE APPROACH OFFICER

(a) The Periscope The periscope is the most important instrument at the command of the Approach Officer. It is by his use of the periscope that he is able to furnish the members of the Fire Control Party the information they need to compute and set the proper gyro angle on the torpedoes as they are fired. Let us, then, before discussing his duties, review briefly the salient features of the periscopes now in use and the techniques of their use.

(b) The two periscopes presently installed in fleet submarines are the type IV in the number one position and the type II in the number two position. Although these are alike in many respects the most outstanding difference is that the type IV contains a radar by means of which ranges may be obtained. The main characteristics of the two periscopes are as follows:

Note, I am unable to line up the columns so the information below is not in proper columnar format


Type II Type IV
Magnification high power 6.0X 6.0X
Magnification low power 1.5X 1.5X
Maximum elevation of line of
sight (above horizontal) 74.5 deg. 74.5 deg.rees

continued)

Page 5-1
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CONFIDENTIAL

Type II Type IV
Maximum depression of
line of sight (below horizontal) 10 deg. 10 deg.
True field high power 8 deg. 8 deg.
True field low power 32 deg. 32 deg.
Ranging Device Stadimeter
Telemeter
Scale Radar
Telemeter
Scale
Outer diameter reduced
section 1.414 in 3.75 in
Optical length 40 ft 36 ft

An examination of the above tables reveals that in order to obtain radar ranges we have had to sacrifice: (a) about six feet of periscope depth, (b) the ability to conduct a visual search above 45 degrees, and (c) 2.3 inches in the size of the tapered section of the tubs. These facts should be borne in mind when selecting the periscope to be used in different tactical situations.

The field of the periscope in low power (32 degrees) is four times the field in high power (8 degrees), but at the same time objects appear only 1/4 as big in low power as in high power with consequent reduction in detail. This can be clearly seen in Plate II.

Referring to Plate II we see that the reticule of the periscope has inscribed on it a series of vertical end horizontal lines. In low power each small division represents one degree while in high power each all division represents 1/4 degree. If the Approach

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[U]CONFIDENTIAL

Officer knows or can estimate the masthead height of the target in feet the number of horizontal divisions covered by the ship between its water line and masthead will be a measure of the range of the target. In the figure the target subtends 5 divisions in high power and 1 1/4 divisions in low power. It would obviously be impracticable to convert this value of angle to range at each periscope observation. The obvious solution is some form of precomputed graph or scale. We know that at a range of 1000 yards, 17 1/2 yards, or 52.5 feet will subtend an angle of 1 degree. Using this relation we can deduce the following formulas:

R(range) = (19.1 h / n)
R(range) = (76.2 h / N)
R = range in yards
h = height in feet
n number scale divisions low power
N number scale divisions hi power

Plate III is a picture of one type of scale ("range omnimeter") which may be constructed. In the figure the masthead height of the target is 100 feet. The arrow of the sliding scale is set opposite the masthead height and the range is read opposite the number of divisions. In this case 1550 yards is read opposite 5 divisions high power and 1 1/4 divisions low power. Ranges obtained in this manner are commonly referred to as "telemeter ranges". Estimates of

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Confidental

ranges should be made to the nearest 1/8 division.

(c) The second method of obtaining ranges is by means of the stadimeter installed in the Type II periscope. The stadimeter relies for its operation upon the formation of two identical images which can, by means of a handwheel on the periscope, be vertically displaced with relation to each other. Normally the handwheel is at the limit of its counter-clockwise travel. To obtain a range, the handwheel is turned clockwise until the target masthead in one image coincides with the target waterline in the other image. The range is then read on the stadimeter scale opposite the appropriate masthead height. In Plate III, a picture of a stadimeter scale, a masthead height of 60 feet gives a range of 2300 yards. Note that the scale is constructed for high power observation. When ranges are measured in low power the computed value must be divided by four.

Note, in paragraph (c), I believe the discussion is about the split images on the stadimeter, which is method separate and distinct from the Omnimeter.

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Rockin Robbins Reply to Second PM from I'm goin' down:

That's no meter, that's a slide rule! I've never heard of a slide rule being called a meter. They refer to it as a "range omnimeter" once and if you notice in figure III it shows that the slide rule is just a straightened out version of the round range input dial of the TDC. It works the same way. If you know the true dimension and the angle it subtends you can obtain the range.

The problem was that Capn Scurvy gives you the information the sub captains would have killed their mothers for on a silver platter because he has taken ever Japanese ship in the ocean (rented them probably) to San Francisco harbor and gone over them with the measuring crew from hell, getting exact lengths, stack, cabin and masthead heights. We didn't have any of that in WWII.

That is why the Submarine Torpedo Fire Control Manual mentions the tool and then ignores it. It was useless. His part about calculating angle on the bow with the device is plain ludicrous, putting the cart in front of the horse. In fact, as shown on page 5-9, the true purpose and use of the AoB scale was to correct the range value for observed AoB estimate, not to derive the AoB from knowing the range! They did not know the range!

The Capn has put a lot of work into this and it works as advertised. But it reduces an understanding of the problems encountered by real sub captains to the status of a MS Pacman video game. He supplies you with the answers and uses the mumbo-jumbo of plausible devices to cover up for the fact that he has only succeeded in supplying another version of the perfect position reporting everybody complained about to begin with. You just have to do a little work to get that same perfect position to cover for the fact that he did it.

In the real war, recognition manuals contained a small percentage of the ships actually sighted. Those that were in the books were so poorly rendered and so well altered by the Japanese from their pre-war configuration that the targets were misidentified much more than half the time. That means they didn't know the length within a factor of three. They didn't know the tonnage within a factor of six. They didn't know the masthead height to within plus or minus 50% of the real height. Now, with all that non-information, start using Capn Scurvy's tools. They're junk.

In reality the only thing that saved the effectiveness of the US submarine fleet was great radar. It was accurate to within 20 or 30 yards at 2000 yards, plenty good enough for hits every time. Every other method they had was little better than guessing.

The only captains that came close to using the US TDC/stadimeter with any effectiveness were Mush Morton and Dick O'Kane. Fluckey learned from them and Sam Dealey so he inherited their knowledge. They liked to use modified fixed bearing methods where range was not important to get hits.

And even O'Kane, after his radar broke down, radioed Pearl and sent a sarcastic remark I paraphrase as "Damn, there goes half my torpedoes." That is the master, allowing that with all the devices pre-radar on the boat he'd be lucky to get 50% hits. That proves my point.
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Captain Scurvy comments via PM to I'm goin' down after reviewing the above PMs:

So, you two are fighting it out through Private Messages? Too bad, I'd like to get into this one, but not thru private messages. I'd like to see him bring this up in open forum!!

I see you showed *** (language omitted by I'm goin' down) this link to the Submarine Torpedo Fire Control Manual found HERE. Taking a look at the plate (images) "III" or "V" in the back part of the manual, it sure as hell looks like an Omnimeter to me!! Having him read Chapter 5 "Duties of the Fire Control Party" and see what the United States Navy thought of the "Omnimeter" may change the *** [his] mind!?! Probably not, he's hard headed as they come.

As far as the ONI Manuals not having estimates for height and lengths is his idea of a joke. He knows they had them. They just may not have been accurate. But, here's the thing. If a Captain returned from patrol saying "That manual stated 100 feet for the XYZ Maru but my torpedo's missed by a wide margin. I think the darn thing should read 200 feet instead". You can bet every other Captain who heard this, changed his manual for the XYZ Maru to match what the experienced Captain had thought. The manual may have been in error, but not for long. Changes would have been made, if nothing more than pencilled in.

Thanks for passing it on.
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Captain Scurvy's comments in a supplemental PM to I'm goin' down:

Ol Double R's (shorthand for Rockin Robbins!) in fine form tonight!!

Quote:
In fact, as shown on page 5-9, the true purpose and use of the AoB scale was to correct the range value for observed AoB estimate, not to derive the AoB from knowing the range! They did not know the range!
They did know the range. At least an estimated range to target. That's the first thing the party wanted to know after getting a "relative bearing" fix on a target. The relative bearing was easy to determine, just position the cross hair of the periscope or TBT on the target and the relative bearing is read off the scale.

The fact that the Omnimeter can be used to find the AoB of a target when an estimate range is known is just taking the principle the manual defines and reversing it. Any Captain would have done the same.

RR, believes what he wants to believe. Frankly, talking to the post down the street would get you farther.
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Post script by I'm goin' down

If CapnScurvy is hauling Japanese ships from WW2 to San Francisco Bay to measure them, I would like to meet him for a drink at the Buena Vista Cafe, a bar at Fisherman's Wharf. I live 45 minutes from there.

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[I'm goin' down]

Quote:
Originally Posted by I'm goin' down
Plate III is a picture of one type of scale ("range omnimeter") which may be constructed.

Rockin Robbins reply.

And that is all you need to know. They are saying that such a slide rule can be constructed if you are at all interested. Figure III clearly shows that the slide rule is nothing more than a horizontal slide rule version of the TDC range input dial, which also includes all the functions of the telemeter. Why they call it a meter is anybody's guess. We are talking about the military and they call things what they are not. It's not a meter, which is an automatic measuring device such as a speedometer or a tachometer.

In any event, reading the entire section, not just taking half of Figure III out of context and then building a high and teetery house of cards, it is clear that they never used target length and time by the wire to calculate AoB. In fact, it is clear by the page I quoted in a previous e-mail that they were smart enough to use more reliable numbers to calculate less reliable numbers.

The least reliable numbers they had were target length and masthead height. They had no confidence at all in those, and for good reason. In fact, on the page I quoted it is clear that the most reliable number they could get was the visual eyeball estimate of the target's AoB!

That is an incredibly damning testimony to the quality of intelligence data on the enemy's ships. Then they explain how to estimate masthead height by counting the number of decks, multiplying by a standard height per deck and then relating that to the masthead height. Resulting accuracy in range yielded from this procedure would be in the realm of plus or minus 25%. Scurvy is pining over 20 yard inaccuracies due to improper game camera position in relation to true periscope position.

Truly, Capn Scurvy substitutes god view visual positions (only the visual part of the game data is defective) and replaces them with god view visual positions. What is the point? There is none. Both are equally inaccurate. Both are false representations.
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[I'm goin' down]

The links to the Torpedoe Fire Control Manaul are screwed up. I have asked Captain Scurvy to post the proper links here, after which time I will insert them in the initial post in the thread. The columns for the periscope readings could not be copied by me in their proper format, so the manual is worth looking at in that regard. The information in the manual was duplicated to a great extent in the OTC mod, per the information in its tutorial, I believe.

[tomoose]

are PMs for a reason. I'm not sure dragging it onto the public forum was a tactful move.
:salute:

[Rockin Robbins]

Let me add to that that you do get to play with a really cool circular version of the slide rule. The Submarine Torpedo Fire Control Manual indicates that this is something that "could be made" Gino indicates that Electric Boat Company made one of thse for each boat. I have no way of determining which is correct.

I do know that the manual was the official training material for submarine personnel. If it merely mentions the device as "something which could be made" and spends no time teaching its use, we can be confident that it was used infrequently. In the historical novel "Run Silent Run Deep" trilogy, Admiral Edward L Beach mentions an attack procedure (they were different for every boat) where the exec backs up the TDC operator using an is/was and unspecified slide rules, among which could have been this device.

In addition, on page 5-9 it says:
(c) Since these formulas are identical with the ones for obtaining range except that L is substituted for h and the value sin Ab added we may obtain the value of the foreshortened length by setting the number of scale divisions opposite the radar, observed, or TDC generated range and read the foreshortened length opposite the arrow on the masthead height scale. We now need to correct this value for angle on the bow. Plate V (http://hnsa.org/doc/attack/index.htm#platev) shows the scale set for the conditions shown in Plate II (http://hnsa.org/doc/attack/index.htm#plateii) assuming an angle on the bow of 40 degrees. Note that in this case the number of telemeter divisions, 12 high power or 3 low power, is set opposite 1/2 the range, 920 yards. This is done because the masthead scale does not go above 200 feet. The foreshortened target length is then 290 feet or twice the value read opposite the arrow. On the second sliding scale the angle on the bow 400 is set opposite the target length 290 feet and opposite the arrow at 90 degrees we read 450 foot the full target length.

I quote the entire paragraph so we don't take anything out of context. Here he is explaining the process of using measurements of mast height and/or target length subtended angles to calculate range. It helps to understand what they are saying to remember the principle that you calculated less reliable numbers by using more reliable numbers.

They are referring to a family of slide rules called telemeters, not just to the "range omnimeter." Note that this slide rule is called the "range omnimeter" not just omnimeter. It's purpose was to calculate the least reliable number (in fact almost unknown) of range. They also use it to calculate another unknown number: target length. The known numbers, those they have confidence in are subtended angle, read from the periscope scale marks, and the AoB which was estimated from visual observation of the target.

In no case were they calculating AoB, because the most reliable way of obtaining that number was by visual inspection by a practiced and experienced observer! In no case was the AoB obtained by timing the length of target across the center crosshair of the periscope. THEY HAD NO CONFIDENCE IN recognition manual target lengths or they would not be calculating them with the telemeters. Length was an unknown to be calculated from numbers they had more confidence in as proven above in the Submarine Torpedo Fire Control Manual.

Therefore, the "omnimeter" did exist, but was called the "range omnimeter" because that was what they calculated. As Figure III clearly shows by reproducing both items, the range omnimeter was merely a horizontal slide rule implimentation of the circular range input section of the TDC. Capn Scurvy has introduced a superb manual version that can be used in game. The Clickable Range Dial mod makes the range input dial of the TDC work too. Scurvy's is much easier to read and use than anything produced to date.

The telemeters, range omnimeter included, were not used to calculate AoB based on target length. They were used to calculate target length, the least reliable number, from AoB, the more reliable number. Capn Scurvy has the function exactly backwards, injecting a perfect target length from his tables derived from perfectly measuring every Japanese ship on the oceans of the world. I assure you that was not done in WWII and could not have been done had anyone thought of it.

The original complaint is that the automatic plotting system of SH4 gives perfect positions, etc, of targets on the map. Using TMO we can get rid of the etc, target ID, silhouette and heading. But we are left with that perfect position.

Capn Scurvy substitutes perfect knowledge of all pertinent measurements of all targets. When correctly run through his omnimeter it yields........(Ta Da!!!) perfect positions of visual targets. Substituting god mode perfect positions with perfect god mode positions is not a solution.

The problem remains and cannot be solved without disassembling the game and recoding it more reasonably. That would be illegal because it is Ubi's property.

But if Ubi did it, here's what I would propose. First of all fix the minor problems with periscope vs data collecting camera position and all the scaling problems that happen with the differing proportions of different screen resolutions and configurations. Then correct the maginifications of TBT, attack and observation periscopes (and apparently naked eye? Capn Scurvy makes a compelling case that that is wrong too!)

Then fix the TDC so that you can update the range without messing up the AoB and vice versa. This would create a way to match periscope bearing to TDC with a button push to simulate the function of TDC operator/attack officer in real life. Nisgeis could come up with more stuff here.

In-game is/was (or similar) and range omnimeter would be nice, but not essential. Then the recognition manual must be altered to contain only pre-war data on some of the Japanese ships found in the game. The actual ships should be modified in masthead height, number of stacks and stack height, altered cabins, and errors in target length should still be contained within the manual, but most importantly, most of the merchants found on the ocean should not even appear there!

Since captains had crews to do the plotting for them and doing the plotting authentically necessarily requires liberal use of the pause feature, AND real captains couldn't stab the button even to go to the bathroom, it's appropriate that automatic plotting be used. But how do you get out of god mode?

Not so terribly difficult. First, assign an error range to each method of meaurement. Radar, plus or minus half a percent. Stadimeter, plus or minus 30%, Active sonar range: plus or minus 10%, passive sonar bearing: plus or minus 4 degrees, get the idea? Now when you plot a sonar line, pick a random number between +4 and -4 and add that to the perfect sonar bearing. NOW you have a non-reproduceable random error sort of like.....REALITY! Do that with stadimeter range. It measures 20,000 yards, pick a random number between 70% and 130% and multiply the 20,000 by that and plot it!

Now if you measure twice you get two numbers, don't you? You are finally in the position of a WWI sub jockey, awash in a sea of error! That's called fun, by the way. They would not agree.

You can see that with SH4 we just aren't going to get there. SH5 didn't try even a little bit. It would be remotely possible to write a whole new front end to SH4 to take the data from SH4 and apply the uncertainty factors to a better plot in-game. However that would be using UBI software, even though it was left unaltered, to power another game. I don't think that would be legal.

[Rockin Robbins]

Had another off the record conversation which will remain off the record, but here's my position regarding use of OTC. It is a well thought-out, elegant and functional mod, which performs its task perfectly. However it is the task itself which is an error of reasoning. Replacing absolute certainty with absolute certainty is absurdity.

I also would have preferred IGD to respect the bounds of a private message. I like CapnScurvy a lot. He has consistently demonstrated original thought, extraordinary ability at producing mods of incredible quality and with few bugs or errors. Left to my own devices I would choose not to even raise the issue of this thread. However, the choice was made for me, leaving me with no alternative but to organize my principles and attempt to explain why I would choose not to use the mod. That is not advocating that anyone else not use the mod.

I've downloaded it myself and plan to use it for the experience of seeing his amazing rendition of an in-game circular range omnimeter, and I look forward to using his optimized periscope views, which are much easier to read than the scopes in the game. But I won't do it in my campaign because authenticity and plausible authenticity is my personal standard in playing. I'm not about to tell anyone else what THEIR standards should be.

IGD asked me what I thought, and in the context of a private conversation I told him why I wouldn't consider using it in a campaign. I never intended this to be a public RR vs Scurvy battle. There is no battle. He does great work, using imaginative methods. I admire his great work. For years he's been a vitally important part of Subsim, and been a great contributer to RFB, and I'll not be a party to tearing him down.

[I'm goin' down]

I took the liberty of deleting the more inflammatory aspects of both of your posts, but if I did not go far enough, my apologies. You each have diametrically opposed positions on the Omnimeter. The bottom line for me is that I understand CapnScurvy's logic, and without doing the actual math, can understand how the Telemeter marks can be measured in degrees, and thus translated into distances. If that is possible, then getting approximate range should be possible, even if the height of a particular ship is unknown. Since we are playing via computer, nothing is lifesize, so I understand why CapnScurvy would provide ship mast heights and lengths in the recognition manual for the OTC. Also, if Telemeter marks are useful in determining range, it makes sense that they can be counted to determine a ship's aspect ratio and Aob. That leaves the question of whether the Omnimeter was used in combat.

On the other side of the coin, Rockin Robbins says the omnimeter was either an imperfect method because the U.S. (1) did not know the mast height or length of the targets, so the height/length numbers provided by CapnScurvy's would have been information the Submariners did not have; or (2) the omnimeter was never used in the War, so it is per se unrealistic. Position no. (1) seems inaccurate based upon my analysis in the preceding paragraph. Postion no. (2) may be the truth.

Without having a WW2 captain to advise us on the state of the art of the Omnimeter during the War, we will never know for sure. RR says that writings from O'Kane and others support his position. He may be right. Irrespective of that, CapnScurvy's OTC is one hell of a mod.

Finally, I add the following. Rockin Robbins and Captain Scurvy are two of the most savvy captains and contributors to the site. Further, Rockin Robbins was my mentor for this forum when I first started sub school, and he graciously awarded me medals for sinking ships back in the day when I was learning how to use auto targeting (even though he may have been laughing under his breadth at my ignorance of submarine warfare -- at least until he sunk an Essex class ship.) CapnScurvy has answered numerous petty questions I have continuously raised while trying top master the OTC and Toyyko's Revenge (the hardest game out there [and I thought TMO dds were deadly!]) I went public with the PMs because CapnScurvy invited me to "take it to the street." I intended no offense, and if I should have cleared it with both of you first, my apologies. Let's see if we get some input for other experienced members.

[I'm goin' down]

My PM to RR took a turn south and the reply ended up having a life of its own. The original PM did not deal with the OTC viability issue. Here it is:

Original PM to RR:

You ought to try the OTC mod with American radar from the beginning of the War. Turn map contacts off. It is quite a game. If you add Toyyko's revenge, forget your summer vacation. Where the heck have you been by the way?

[Hitman]

First of all, I'd like to point out that I absolutely share Rockin Robin's views on uncertainty, to which I would like to add that guys looking through a periscope in war conditions also had to contend with lots of stress, lack of sleep, fogging of scopes, targets that modified their appearence and sometimes were not even in the recognition manual plus lots of targets incorrectly identified by the tracking party. It is no wonder that the guy on the plot did therefore conduct it by averaging the dots, and not by trying to connect them with a solid line, and that eyeballing was considered the best method of determining target's AOB, even if looking through a monocular periscope -what causes to lose any depth perception.

That said, the discussion is in general of interest for pre mid 1942 WW2 warfare and eventually for WW1 warfare (Which was conducted quite differently due to the lack of TDC --> Look at how SBoats did the job with the "Banjo") because as soon as radar appeared and night attacks or at least night tracking was possible, the accurancy of it could not be beaten by any optical device, let alone a periscope. It is well known the sarcastic comment of Dick O'Kane when the radar failed in one of his patrols, saying "Well, there go half of my torpedoes", and for anyone who has readed books on the matter, it is obvious that using periscope and visual as only aid caused lots of misses - LOTS and not just duds. Stories of miscalculation of speed are by dozens among history books.

Scurvy's mods are brilliant and besides allowing precise measuring they fix many incongruencies and bugs, but there is a compelling case in that they offer the player way more accurancy than what the real captains had - not the least because even if the real captains had accurante information (And it was very possible for a good amount of targets, specially warships) in most cases identification of the target was impossible, and simply a best guess was made after the attack by looking through ONI208J, while the player has just about a dozen models to choose from.

There is an evidence that substantially backs up what we are defending here: Tonnage claimed by commanders was greatly inflated, as stated by JANAC after the war, and that is something that could only happen by MISIDENTIFICATION of targets. And, if they were misidentified, there goes any hope of the precise figures in ONI serving for anything else but pure luck and coincidence in measures with the real target.

So, a conclusion, I'd like to say that IMHO Capt. Scurvy is not wrong in that accurate data would provide accurate ranges, and in that accurate data were sometimes available for the captain, but he probably does not consider that identification in the game is infinitely much easier than it was in real life, reducing that essential variable of the problem to almost zero.

My 2 cents :salute:

[I'm goin' down]

good post. I read your pdf on Manual Targeting at 100 Percent Realism when I began playing SH4. I thought at the time that is better than sliced bread. It saved me until I was smart enough to realize I was a dumb ass. It was still a great tutorial.

[CapnScurvy]

The link to the USS Cod "Omnimeter" post, started by Gino is found HERE (http://174.123.69.202/~subsimc/radioroom/showthread.php?p=1397786#post1397786).

The link to the referred US Navy document "Submarine Torpedo Fire Control Manual (http://www.hnsa.org/doc/attack/index.htm)".

A long time ago Rockin Robbins and I had the conversation regarding what is historically accurate and what is "playable" regarding a game that attempts to be realistic. When I developed SCAF (years ago now) to correct the mast heights (reference points) by which the stadimeter would base a manual found range for a firing solution, I was told I was taking too many liberties with giving accurate range to a player. The idea of having a height measurement that was reasonably accurate irked some of the community because they felt this wasn't realistic. They failed to consider that any Captain worth his "bars" would have done his best to readjust inaccurate measurements (when suspected), so his next encounter would prove productive. We aren't talking about getting a "do over" by simply hitting the rewind button with the game. The real life Captains, with real families, with real crews lives at stake, didn't get a chance for a "do over" when a missed firing solution produced a poor result. If the Captain figured the ONI Manual was faulty with poor measurements, he would have corrected his copy for improving any chance of a future encounter. When he returned to base (providing he did return), I'm sure he wouldn't have kept it a secret from the other Captains either. The point is, correcting height/length measurements would have been "realistic" if they were found to be in error.

TMO 2.2 has the Hiryu mast height set at 20 meters. This is the same mast height as the SH4 stock game had when the game was first released in March 2007 with version 1.0. The corrected mast height is nearly 17 meters taller than the stated TMO mast height. This isn't "camouflage" that put this kind of inaccuracy into the game. It's a pure and simple error, that isn't even close to reflecting what some would like to say is "realistic" game play. Realistic or not, I'm going to correct the height/length measurements, so a player fails on his own poor firing solution skills, not some figure pulled out of thin air that isn't even close to being accurate.

What are the types of errors one will encounter even with an accurate measurement in height/length? For starters, there is no such thing as having accurate height measurements that will provide exact range to target using the stadimeter!! It won't happen. The game has the stadimeter set to give inaccurate range 95 percent of the time. You want nuts on accuracy, use the games sonar by taking it yourself (funny I've not heard of anyone bitchin' about the games sonar realism?!). Or, use the TMO 2.2 radar setup. It will give you down to the meter range accuracy!! The stadimeter won't, no matter how accurate the measurements for height may be. RR's idea that a Gods Eye view is found when correcting measurements that require human input is misplaced on OTC's corrections. The game accomplishes these range errors, even with accurate measurements, by varying the accuracy of the stadimeter by providing different range to target depending on the distance the test is taken. One would think, an accurate reading would be found at any distance after the measurement for height was corrected. Nope, not at all. With the same corrected height at one distance (lets say short range 1000 meters), the range could be accurate (I consider the range to be "accurate" anywhere within 10 meters of the true distance), but at 2000 meters the range would read 40 meters off, at 3000 meters the range inaccuracy would read 80 meters off, and so on. What's accurate for one distance is off for another. Like I said, this is built into the stadimeter. Another way to get an error is by missing the stadimeter measurement by just one pixel row when you're placing the waterline image on a mast top. Depending on whether the target is near or far, the misplacement of only one pixel line can be anywhere from 5-10 meters in range inaccuracy, into the 100's. This is built in also, to reflect the realism of closer targets will be more accurate than further away ones. Then there's the fact that the stadimeter focal point isn't positioned at the subs (except for the S class ones) periscope position. It's independent of the periscope view, which gives an error in range depending in which direction the scope is pointed. The two side directions are centered, the front compared to rear directions are not equal.

My first point is there is no way giving accurate height/length measurements is going to give you a sure fire accurate stadimeter range to target!! Not going to happen.

[I'm goin' down]

sheesh, with all those inacurracies, I might a well revert to auto targeting. :D But that is porbably inaccurate too.:hmmm: (don't answer, as I do not want to know.)

[Rockin Robbins]

The problem is that there is no way to make SH4 anywhere near perfect. Wanna do it my way? The ole Capn will be happy to tell you six reasons it isn't authentic. Wanna do it his way? I'll be glad to tell you six ways it's inauthentic. Heck, we know each others' positions so well we could trade places and do just as well.

It all comes down to personal preference. How do you like to play the game? I suggest that you don't know unless you've tried, whether you'd like to use OTC depends on whether you've tried it and liked it.

I thought I'd HATE Ducimus' evil airplanes that can see you underwater, infrequently to astounding distances. The first time I loaded up TMO with fear and loathing I was in shallow water, lining up for a shot when WHAM! the water around me exploded. The bomb missed, but the targets were alerted, I was in the crosshairs and the entire situation reversed in a second. I loved it and still do. I love uncertainty in the game.

So I think Ducimus has it right in TMO with leaving auto targeting on and taking away the silhouettes, target IDs, heading and speed, leaving you with just a position point. It's not perfect but it's an acceptable compromise.

But you make up your own decision. That means trying out the alternatives and making a choice. When I argue my position in this, I'm arguing a philosophical argument, not attacking CapnScurvy. And I AM going to load up OTC and give it a shot, if only to experience the wrath of Tokkos' Revenge, which I understand can't be run without OTC, is that correct?

The final analysis is that this is a flawed game. We can make some changes but most often it's a zero sum game. To get this realism over here you lose some realism over there. It can drive you to drink.

But that's what we have. And don't forget that it's STILL the best WWII submarine simulator in the world, along with SH3. Those two lead by a large margin over anything else, so where do we have to go? We're forced to have fun with what we have, and that's not so hard.

Warts and all Silent Hunter 4 is a great sim.

Hey, I was north of Rabaul, finding ships in the harbor with passive sonar and pinging them for range with active. Which is really strange because there was solid land between me and them!:D Also you get the range before the echo returns: alien technology there! And in the background is silence. The ocean if full of noise that makes a sonar operator's job much more complicated than we have in SH4. So even the sonar if flawed, even if no one complains about it.

[I'm goin' down]

Hint to RR. If you try Tykko's Revenge, enable Silent Running when attacking. Enable it early. If it is not enabled, merchants will evade, and for warships -- you do not want to know. Here is what CapnScury posted in response to one of my questions in the OTC thread:

The Tokko's Revenge mod doesn't change the radars "ability" to pick up radar blips, either plane of ship (that was modded into the "main" OTC mod). Tokko's Revenge doesn't really "add" additional planes either (least wise not as far as numbers go). OTC and the Tokko's Revenge mod actually "lowers" the stock plane numbers and their probability of being spawned. I did add a Kamikaze plane that carries a greater payload for attacks (and tried my darnedest to have it crash "head long" into it's target, with no luck) starting in mid-late 1944. What Tokko's Revenge does, it adds greater AI "perception" to the enemy planes and warships to find and attack you. Their ordinance has increased fire power to make it easier to accumulate damage if you let them fire on you. It will take a longer time to have the enemy lose interest in your presence. You may also find that the "old" procedures to evade the enemy may not work as they use to.
__________________

Note, OTC is compatible with TMO 2.2, but not TMO/RSRDC. It is compatible with stock/RSRDC.

Why do I get different range from sonar readings?! It makes it difficult to a target's plot course with sonar.

[CapnScurvy]

I've got one more point to make in this thread, regarding the Omnimeter. The "Submarine Torpedo Fire Control Manual (http://www.hnsa.org/doc/attack/index.htm)", in my view, was a "pamphlet", a "hand out" coming from hours of training in a class room. I've been to many of these types of training sessions for my employers over the years. You get something to take with you for future reference, but the main instruction on the subject in question is done in a class room. Where an instructor lectures on the subject and you take notes and ask questions as the class progresses. The fact that an Omnimeter is mentioned at all in the manual; provides pictures; and even spells out how to use it, tells me there is some merit to the device. How much classroom time was spent on the Omnimeter? We may never know, but, I'm guessing there was some. In a "Rockin Robbins" tribute, let's listen in on one in progress:

"Put your hand down Lieutenant Robbins, you can't go to the head!! Class is almost over, you'll have to hold it. You'll not be going to the head when a Fubuki Destroyer is bearing down on you!!

Lieutenant Scurvy has a valid question, Why can't the Omnimeter be used to find the Angle on Bow when an estimate of range to target is known? Yes, you simply reverse the procedure we just discussed regarding checking range to target when an estimated AoB is known. Simple mathematics men, 3+5 or 5+3 both equal 8 no matter which way you choose to put them.

Next question.

Yes, Lieutenant Hitman, you can help Robbins to his feet.

Class dismissed!"

The Omnimeter can be used several ways, it didn't take me long to "read between the lines" to see it's usefulness. I suspect any other student could see the same.

=============

I wish to comment on this thread in general, started by I'm goin'down. The question of the historic value of the Omnimeter is a valid one, but how it was presented, with the use of Private Messages is just wrong! What a person says in private is just that, private and should be kept that way. When I stated "I'd like to see him (meaning RR) bring this up in open forum" I meant just that, if he brought it up. He didn't, I'm goin' down did. Quoting word for word the private conversation.

I'm not in favor of this kind of "presentation" at all. That's why I've made a couple of points in this thread and plan to leave it at that. I'll not "tit for tat" the specifics of what was said, not when it was done through a private message! If anyone wishes to comment on my work, I expect them to bring it up to me with their own points, not handed out through second hand means.

I respect Rockin Robbins for his candor and insight. I enjoy reading his thoughtful ideas and posts. I trust we will still always be friends in a community we both love and share. But, I'll not give this thread another reply. It just doesn't deserve it.

[Rockin Robbins]

When I stated "I'd like to see him (meaning RR) bring this up in open forum" I meant just that, if he brought it up. He didn't,

Thank you Capn. I wouldn't have.

[I'm goin' down]

Me neither. I would not have thought of it, had CapnScurvy not mentioned taking it to the street.

I have one more question though--unrelated to the thread. My sonar man gives me ranges that are quite inconsistent. Like over 1,000 yards difference between readings. Is he inexperienced or is the sonar unrelieable? How does it happen?

Incidentally, using Tokkyo's Revenge on the first mission from Pearl in 1941 sends you up the Bungo Strait to drop of a "Secret Agent" man (good name for a song!) I've not completed the misson on three attempts. Twice sunk by a dd cannon fire in the Strait and once by depth charge from a small split frieghter backing up the dd that I torpedoed. The Japs can find you with AI even if your boat is giving a low profile, with silent running engaged at 1/3 speed.

[Rockin Robbins]

Sounds like TM before TMO when Ducimus went all soft-hearted on us. It got pretty brutal sometimes.