Ranging and fire control problem

[GSpector]

To make matters worse, I do believe UBI stated that there was an error in Torp speed and suggested only firing at Slow since the Fast setting calculates for a faster speed than Torp's actual speed causing Torp to hit Aft section of moving Targets

[anthrax]

The standimeter is pretty accurate. Its just they you have to be careful exactly on where you measure from.
1.) Measure from the higher point horizontal point on on the mast. (i.e, it highest "cross" shape.)
2.) Always exclude the flags.

Here are some examples. Here an Iowa class at 1400 yards. (~0.7 NM)



Map view

[anthrax]

Here is a second example. A T3 tanker.

[Charos]

Anthrax

I welcome all testing but firstly the most glaring observation with your conclusion I can make is that the T3 example is not ranged properly on the stadiometer.

Therefore repeatability of your conclusion is wanting.

IE: On your T3 Tanker your Stadiometer is under the waterline by 0.5 Graticule markers (which scews your result) instead of the TDC reading of 2.75 markers it should only be 2.25 markers (Useing your mast cross member theory)

In the T3 screen shot moving the Periscope X axis up to the waterline 0.5 markers would put the stadiometer at the very top of the T3 mast, not on the mast cross member.

Since the Stadiometer is a visual tool at great range error's will be lost - testing should be conducted on closer targets where it is easier to read the stadiometer markers off manually.

We need this issue resolved - It affects the entire games ability to connect torpedoes with a target which is what the general idea is in the first instance.

[Torpex752]

I dont recall the game manual telling us how its to be used. In navy Contact Coordinator School I was taught that its waterline to mast top, that was the same method used during WWII, I am quite sure of this.

Frank

[Charos]

Originally Posted by Torpex752

I dont recall the game manual telling us how its to be used. In navy Contact Coordinator School I was taught that its waterline to mast top, that was the same method used during WWII, I am quite sure of this.

Frank

Thats the rational assumption Frank and the one we have to work with.

As soon as we start picking arbitrary points on a ship - the results can be fudged to fit whatever we like.

[BlackSpot]

Originally Posted by Charos

Anthrax

IE: On your T3 Tanker your Stadiometer is under the waterline by 0.5 Graticule markers (which scews your result) instead of the TDC reading of 2.75 markers it should only be 2.25 markers (Useing your mast cross member theory)

In the T3 screen shot moving the Periscope X axis up to the waterline 0.5 markers would put the stadiometer at the very top of the T3 mast, not on the mast cross member.

Hmmm...I've just tested this. It doesn't seem to matter whether it aligns with the waterline or not. Try it.

[Charos]

Originally Posted by BlackSpot

Hmmm...I've just tested this. It doesn't seem to matter whether it aligns with the waterline or not. Try it.

I assure you it does matter because thats your REFERENCE Point from which the stadiometer is measuring from - Your measuring the ship not the water in front of it.


I just tested a T3 with a S-Class broadside - BOTH stationary.

T3 - Had a loadout of Fuel.

Attack scope at high magnification used.

When T3 fills FOV broadside my sub is at 1,170M from target-which gives again a FOV of 9.3 Deg.

Stadiometer reads 1,040M range or an error of approx 12%. TDC Graticule markers read off 5 of them. Which calculates out to approx 0.3 Deg per marker (They should actualy be 0.25 Deg per marker)

T3 is 190M long with an 8Deg FOV I should see it fill my field of view at 1,360M.

This test represent much the same as before - my other tests reveal approx 17% deviation and this one provided 12% - still ballparking the same.


EDIT: A Torpedo at 36K released with this TDC setting would take approx 7 Seconds longer to reach target as the real distance is 130M further away than the TDC calculation.

[akdavis]

No, it doesn't matter. You can't bring the mirror image down below the original, no matter the orientation of the periscope. This:



Returns the same, correct measurement as having the waterline centered. There is no variance. For the Mogami, the correct measurement is returned when using the first crosstree from the top. This is not the case with all vessels.

For the Medium Modern Composite in the artillery training mission, the correct range is obtained using a point above the very tips of the masts:


Also, you are wasting your time using the ruler on the navmap to compare stadimeter range to actual range. Simply turn the TDC on and compare the TDC plot on the attack map with the ship's actual position.

[Charos]

Originally Posted by akdavis

No, it doesn't matter. You can't bring the mirror image down below the original, no matter the orientation of the periscope.

Also, you are wasting your time using the ruler on the navmap to compare stadimeter range to actual range. Simply turn the TDC on and compare the TDC plot on the attack map with the ship's actual position.

Firstly appologies to Blackspot because he and Akdavis are correct as far as the operation of the splt image stadimeter.

The split image utilises whatever elevation/depression is currently on the scope and then via the split image of known height moves a given angular movement to obtain range.

The scope takes the reading from its current declination as the reference point.

Ok good I have my head around that now.


Point 2: Useing the attack map provides the exact same distance error as the navmap (I just tried it with the T3 - no change) Why should it be any different?

EDIT: It is easier though when trying to manually convert graticule markers to range via math to use the X-Axis of the scope as it starts the measurement on a full marker - which eases
reading them off.

[Charos]

Just did some testing with a Mogami this time.

It seems to me we are dealing with a Hydra.

Krupp's mod covers some of this: http://www.subsim.com/radioroom/showthread.php?t=109953

I see the following:

#1 Models proprtion's do not seem consistant - as Krupp has found.

#2 Field of view of attack periscope and most likely TBT are incorrect (I have not focused on the TBT as yet)

#3 For those attempting to go full manual (without TDC) the graticule markers are also incorrect at something like 0.3 Deg instead of 0.25 Deg.

#4 The magnification factor of attack periscope seems more like 5X not 6X which is obtained by the field of view in the game world.


Depending on what ship you range on depends on what result you end up with as the results vary with target model as well as the viewing instrument utilsed.

The combinations of which all throw out measurements as few combination's show consistancy.

[akdavis]

Originally Posted by Charos

Point 2: Useing the attack map provides the exact same distance error as the navmap (I just tried it with the T3 - no change) Why should it be any different?

You misunderstand me. I'm saying it is easier to see if the measured distance and the ship's actual position coincide by observing the TDC solution marker on the map in comparison to the ship's actual location. This is more accurate than trying to determine an error on the order of 100s of yards with a tool that measures in nautical miles.

[Charos]

Originally Posted by akdavis

You misunderstand me. I'm saying it is easier to see if the measured distance and the ship's actual position coincide by observing the TDC solution marker on the map in comparison to the ship's actual location. This is more accurate than trying to determine an error on the order of 100s of yards with a tool that measures in nautical miles.

I see where your coming from - this is now I do it.


To start with im a Metric guy so im working in Meters.

On the Nav map you can drill down to 100's of Meters IE: 1.1KM, 1.2KM, 1.3KM etc

You just mark off JUST before it rolls over to the next unit length.

then its not to bad to at least cut that into 50% or 25% intervals IE: down to approx 25M chunks.

Which is close enough when in general 25M is only 1/40th- 1/60th or so of the total Range.


Things seem to be out in general by 12% to 18% so 2.5% to 1.5% error isnt that bad compared to what we are seeing elsewhere.

I only really started to take notice of all this when I shelved the TDC to go full slide rule in the S-Boats then things really went wrong when I tried to get a solution on anything.

EDIT: Now with Patch 1.2 we will have to test again to see if they didnt SNEAK any changes past us.

[Charos]

Well they certainly changed the high range periscope FOV BUT they went too far the other way this time.

The Iowa is 270M long and has a mast height of 46M.
Real 8 Deg FOV scope to see the Iowa fill the entire screen would require a range of
135M/Tan 4 Deg = 1,930M .

___________________________________

The data from the Patch 1.01 Iowa test:

Note the Iowa in SH4 fills the 6X attack scope at approx 1,680M.(see attached screen shot)

Also note that the TDC via the stadiometer provides us a range of 1,406M.(see attached screen shot)

So that attack periscope markers on 6X and its associated FOV work off 0.29 Deg per graticule marker for its 9.3 Deg of view.
__________________________________

Now the same test in 1.02 provides:

Note the Iowa in SH4 fills the 6X attack scope at approx 2,850M

Also note that the TDC via the stadiometer provides us a range of 2,450M

So that attack periscope markers on 6X and its associated FOV work off 0.17 Deg per graticule marker for its 5.5 Deg of view.
__________________________________


1.01 shows a TDC to real range variance of 19% less and 1.02 shows 16% less.

Still ballparking around the same 17% mark as before now its just blown past in the other direction.

Problem hasnt changed its just been moved in the opposite direction.


EDIT : We now have approx a 9.7X Magnification attack scope. (Should be 6X)

Hopefully everything I typed makes coherent sense as Im still awake at midday after doing night shift.

[Charos]

If anyone is still following

I turned my attention to the Observation Periscope in patch 1.02 .

Low and behold the Observation Scope - seems PERFECT.


The observation scope seems to be exactly 8 Deg FOV in high range and each
graticule marker is spot on at 0.25 Deg per marker.

This coupled with Krupp's excellent work on fixing the mast sizes and models now gives us an accurate fire control system.


On my S-Class the outermost tube diameter and head seems the same on both attack and obsrvation scopes .

The Observation scope I guess may be easier to spot as fas as the AI is concerned though, in any case there is now a working realistic solution useing the observation scope for the time being.