Stadimeter question

[jlry]

When using the Stadimeter, is it necessary to line up the water line of my target with the center line of the periscope? I ask because after viewing the posts here on subsim, and watching many Youtube videos I've gotten confused. Half of them line up with the water line of target, and some do not. It seems like they all appear to get the correct data as they are successful in sinking their target. I've had limited results with Stadimeter, and have been using Sonar to acquire my range.

For example:
Stickied threads above have a few guides.
http://www.subsim.com/radioroom/showthread.php?t=111998 - This guide lines up water line with center of periscope.

http://www.subsim.com/radioroom/showthread.php?t=108689&page=9 - Video posted here, he doesn't line up the water line. http://www.youtube.com/watch?v=rqPqvi_fJYk

There is numerous cases of this. I just want some clarification :)


Thank you for taking the time to read my post, and for any info/advice.

Silent Hunter 4 v1.5
Real Fleet Boat 2.0

[Aktungbby]

Superior tech help to arrive shortly...meanwhile welcome aboard :Kaleun_Salute:JLRY!

[THEBERBSTER]

Lining up the Periscopes horizontal line with the targets water line is what I understand to be the correct way.

Someone who uses the stadimeter in a certain way may well have devised a system that works for them.

Using the stadimeter frequently I guess you know what works and what doesn't.

[jlry]

Thanks for the welcome, and the replies! After searching through the install directory I found the manual(lol, I honestly have no idea why I didn't check here first). It doesn't exactly say line-up center of periscope to water line of target, but it has an illustration that measures mast height from the water line. I will take this as my answer :) Again thanks for your time!

[magic452]

Welcome to the boat mate. :salute:

In my experience it's not necessary to line up the waterline but I find it helpful to do so, I seem to get better results that way. I try to do everything exactly the same every time.

Opening the torpedo doors, setting torpedo speed and depth and exploder etc well ahead of time, depth at 15'. That will sink most all merchants and even many warships, you can always reset things later if necessary but you'll not forget to do so in the heat of battle. Nothing worse than missing or doing little damage because your fish were set to slow speed or 5 feet or the doors weren't open:/\\!! :/\\!!

A couple of things about using the TDC/PK shooting method.
When using the data entry tools always input the data in this order.

Turn on the PK.
Input Speed first.
Input AoB next and
Last thing is range and bearing.
It will make a difference.

Magic

[Jimbuna]

Welcome Aboard :sunny:

[banryu79]

When using the Stadimeter, is it necessary to line up the water line of my target with the center line of the periscope? I ask because after viewing the posts here on subsim, and watching many Youtube videos I've gotten confused. Half of them line up with the water line of target, and some do not. It seems like they all appear to get the correct data as they are successful in sinking their target.

Be advised: I speculate here, because I always used manual targeting BUT never ever ever used the stadimeter to acquire range (there are other methods I prefer).

I recently learned that if you set up the TDC for a so called "Straight Shot" (aka a shot with gyro angle = 000°) having the speed of the target and AOB correctly estimated is enough (aka, range does not matter).

If in the videos you referenced the virtual kaleuns where in fact performing "Straight Shots" the range estimation they took with the stadimeter did not influenced the result a bit, and this could explain why you saw what you saw :)

[P_Funk]

I always thought that the advantage of the split prism stadimeter was that you didn't need the horizontal line at the target's waterline because as long as you put the waterline of the ghost ship at the top of the mast of the fixed ship that you would subtend the correct angle anyway.

I could be wrong though. :hmmm:

[razark]

...as long as you put the waterline of the ghost ship at the top of the mast of the fixed ship that you would subtend the correct angle anyway.
That's my understanding, and I haven't had too many problems doing it this way.

[TorpX]

That is my understanding, as well.

[MCM]

and on the opposite side? Do you take the highest end of a mast or do you take the highest line of the flag of an enemy ship?

greez
McM

[Crannogman]

and on the opposite side? Do you take the highest end of a mast or do you take the highest line of the flag of an enemy ship?

greez
McM

I think that can be variable; OTC, for instance, uses different reference points on the ship for different vessels

[CapnScurvy]

With Optical Targeting Correction (http://www.subsim.com/radioroom/showthread.php?t=181172) you follow the Recognition Manual's cues as to where to place the Stadimeter's water line image. Each ship can be different. OTC uses the most visible point, then has the reference point marked in red to indicate the spot. The reference point could be a mast top, funnel, super structure, flag mast, carrier flight deck.

Do you take the highest end of a mast or do you take the highest line of the flag of an enemy ship?

greez
McM

That's just the reason OTC has several ships using the top of the flag (where it's attached to the mast) as their reference point. On some ships the flag mast is the tallest point, yet if you look closely at it, some flag masts aren't visible at all......the flag is just waving in the breeze. Where the OTC Recognition Manual has a national flag added to the picture, use the top of the flag's attached side (whether the mast is visible or not) for the height reference point.

All OTC height reference points are fairly accurate. On the contrary, the stock game and other mods have various measurements. Many are off by 30% of what they should be, some by 50% inaccurate.

Getting back to jlry's original question.....No the U.S. Stadimeter does not need to have the waterline lined up with the horizontal line of the periscope to take a reading.

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

I realize this thread is nearly a year old, the first linked thread (Hitman's Tutorial for 100% Realism Manual Targeting (http://www.subsim.com/radioroom/showthread.php?t=111998), of 2007) quickly points out the problems the game has with measurements (least that's what Charos points out in the #8 reply):


I see a problem :

In your example mast height is 66 Feet.

TDC Stadiometer range = 547 Yards.

Each Graticule marker is 0.25 Deg (Supposed to be that is)

Mast height = 7 Markers high.

7*0.25 Deg = 1.75 Deg.

Range = 66 Feet /Tan 1.75 Deg = 2,160 Feet. which = 720 Yards.


If you look at your game map thats how far your sub WILL be from the target .

Check it I will be interested to see what you find.


EDIT: To get a range of 1641 feet (547 Yards) out of a mast height of 66 feet

Would require a Graticule angle per marker of approx 0.33 Deg on the high range attack scope.

Or in your example 7*0.33 Deg = 2.31 Deg mast angle.


The problem was the height measurements are inaccurate, plus the Periscope's Graticule Marks (Telemeter Divisions) are inaccurate too! It's little wonder there were issues found with the games manual targeting from the very beginning. That's why OTC was made, to correct these inaccuracy's.

These may be older threads, but the problems with manual targeting are still evident today without OTC.

[Sniper297]

"yet if you look closely at it, some flag masts aren't visible at all......the flag is just waving in the breeze"

Biggest problem with using mast height at long ranges on a computer, a distant mast can be one pixel wide or zero pixels (invisible), never half a pixel or 3/4 pixel since computers don't do that. What would be a faint thin line in real life is not there on a computer simulation because of the display limitations.

I got interested in OTC after reading this old thread, so I downloaded it and am reading the docs now. My biggest objection to manual targeting has always been "too complicated" since in real life I would have an entire attack team keeping the plot, cranking inputs to the TDC, fiddling with slide rules and the IS/WAS, and of course setting the torpedo depth and opening the outer doors so I wouldn't have to do all that myself.

Reading the PDF on the omnimeter hasn't changed that opinion - it goes through calculating the range to the exact yard, then moving stuff on the slide rule to calculate AOB based on actual target length versus the visual apparent length. Assuming I've identified the target correctly, of course, which is difficult to impossible at long ranges.

The PDF doesn't mention the time factor, "The computer found range in the Position Keeper is 1468 yards to target. That’s reasonably accurate!"

AT THIS MOMENT it's accurate, whoops, the sub is moving and the target is moving, the range is constantly changing, by the time I make the adjustments on the omnimeter and enter the data into the TDC, that 1468 yards range is ancient history.

How do you compensate for the time factor? Or do you just accept that the data is no longer accurate but "close enough for government work"?

[HertogJan]

I guess by trial, error and experience.

It's the same when you plot the target's true course and speed on the Nav.map with radar.
By the time you move to the A-scope from the PPI screen, read the distance and look up to the bearing dial, go back to the Nav. Map and select the appropriate tool (triangle thingey :know:), about 10sec. will have passed (if you selected the correct tool otherwise 12sec. will have passed)... Where to put the first marker?!?
Put it where the sub is 'now' and draw the line at xxx degree bearing will put you +-150yrds off... Not a big deal IF you do it the same way each time, mess up once and you'll be off by a couple of degrees and that will mess up your plot.

[banryu79]

If you are setting up a 0° Gyro shot range doesn't matter at all.
Range matters more and more the larger the Gyro angle is.

[CapnScurvy]

My biggest objection to manual targeting has always been "too complicated" since in real life I would have an entire attack team keeping the plot, cranking inputs to the TDC, fiddling with slide rules....

How do you compensate for the time factor?

Manual targeting is no picnic. Lots of things to consider. That's why I mention you should use the Pause key to your advantage in my "High Realism Tutorial (http://www.subsim.com/radioroom/downloads.php?do=file&id=907)". The authentic "Fire Control Team" was made up of 12 to 15 men. Each having specific tasks to do, checking and double checking the Firing Solution. The "Submarine Torpedo Fire Control Manual (http://archive.hnsa.org/doc/attack/index.htm)" outlines the duties/ objectives of the team. In-game its just one person simulating the duties.

Use the Pause key to work out the plot on the Navigation Map (yep, the map tools will work with the game paused). Same with using the Omnimeter......pause the game as you use the slide rule, or count the Telemeter Divisions of the periscope. Since you're doing this yourself, use the tools available (like the Pause key) to help.

You shouldn't think of this as being a cheat or unrealistic......after all, since when have you ever heard of a Captain taking control of the anti aircraft gun!?! I've yet to hear someone say.... "manually firing the Deck Gun isn't realistic". It's fun.....so allow the game to be fun learning manual targeting by using the authentic tools available.

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

If you are setting up a 0° Gyro shot range doesn't matter at all.

Absolutely true.

But then again, if it were that easy, why didn't the U.S. Navy just make a single memo with that one sentence to all Captains, rather than the text book I linked above called "Submarine Torpedo Fire Control Manual"?

[TorpX]

If you are setting up a 0° Gyro shot range doesn't matter at all.


This is technically true, but ultimately misleading.

You will want to know what the target's speed is, and good luck estimating that without having any range data.

[banryu79]

You will want to know what the target's speed is, and good luck estimating that without having any range data.

I concur.
I mean that, for example, with the 4 bearing method, or because you alredy have got a good speed estimation (precise radio report, past speed estimation for wich you do not need high precision range data) you can find yourself in plenty of situatiuons (IMO of course, and speaking in the context of the game) where you are ready to sink 'em without knowing their range to the yard (or meter).

And in case of small or null gyro angle with a shot aimed amidship, target speed and course estimations are far more dominant than range in the outcome... or at least this is what I experienced (in the game, of course :D)


But then again, if it were just that easy, why didn't the U.S. Navy just make a memo with that sentence to all Captains, rather than the text book I linked above called "Submarine Torpedo Fire Control Manual"?

Yes CapnScurvy, I know about the fire control manual of the USN (I have quickly skim throught it a year ago) and I agree... But I was just speaking in the context of the game, exclusevely in the context of the game.
EDIT: I've just read your tutorial, fantastic document for newcomers in SH4 and in manual targeting (and I too will be a new player of it sometime in the future so I will be able to appreciate the service of the PK... I'm currently testing my kaleun-ness with SH3). Thanks for your guide!

[Sniper297]

Hmmm, I tried it with manual targeting but map contact updates as "training wheels" but apparently that disables the recognition manual, I can't activate the omnimeter, and using Optical Targeting Correction for 1.4 and OTC_1.4_Realistic Scopes for 16 to 9 Aspect Ratio (1920x1080 monitor) I have no fine scale hash marks on the scope.

As for "range doesn't matter", best I recall it was Beach who called it the "angle-off" method, where you guesstimate the speed, then lead the target by 10 to 15 degrees depending on the approximate speed. Set the fish for zero gyro angle, then set the crosshairs 10-15 degrees right or left (depending on target direction of travel) and fire when the target is in the crosshairs. If the lead angle is correct it's correct for any range, the problem is that at long range the target has more time to see the wakes and maneuver to avoid. I've used that method myself with manual targeting, but it's the same as auto targeting in that regard - closer is better, inside 1000 yards the target has less time to see and react, and the errors don't have as much distance to multiply.

[HertogJan]

Hmmm, I tried it with manual targeting but map contact updates as "training wheels" but apparently that disables the recognition manual, I can't activate the omnimeter, and using Optical Targeting Correction for 1.4 and OTC_1.4_Realistic Scopes for 16 to 9 Aspect Ratio (1920x1080 monitor) I have no fine scale hash marks on the scope.



There must be a Mod hiccup somewhere, I switch over to complete manual targeting not one month ago (not using the Omnimeter (sry CapnScurvy)) the rec manual and the tool both work with map contact on (used the same "training wheels" method as you).
Use the 16:9 ratio as you too.

[Sniper297]

Well, it's possible I missed something. After reading through all the included docs I understood that what I needed was;

Optical Targeting Correction for 1.4
OTC_1.4_Realistic Scopes for 16 to 9 Aspect Ratio

From what I'm seeing it appears that I use either OTC_1.4_for 16 to 9 Aspect Ratio OR OTC_1.4_Realistic Scopes for 16 to 9 Aspect Ratio, not both? Don't care about deck guns so I didn't bother with the patch, should I also have OTC_1.4_Realistic Scopes installed or is OTC_1.4_Realistic Scopes for 16 to 9 Aspect Ratio a replacement for that?

[CapnScurvy]

Well, it's possible I missed something. After reading through all the included docs I understood that what I needed was;

Optical Targeting Correction for 1.4
OTC_1.4_Realistic Scopes for 16 to 9 Aspect Ratio

From what I'm seeing it appears that I use either OTC_1.4_for 16 to 9 Aspect Ratio OR OTC_1.4_Realistic Scopes for 16 to 9 Aspect Ratio, not both? Don't care about deck guns so I didn't bother with the patch, should I also have OTC_1.4_Realistic Scopes installed or is OTC_1.4_Realistic Scopes for 16 to 9 Aspect Ratio a replacement for that?

The main Optical Targeting Correction for 1.4 corrects the following resolutions:

1024x768
1152x864
1280x960
1360x1024
1600x1200
1792x1344

All of these resolutions have an Aspect Ratio of 4:3. It's the different Aspect Ratios that make the difference between the various possible screen sizes that need to be corrected.

To correct a 16:9 Aspect Ratio (1920x1080 resolution), there is a specific folder called "OTC for 16 to 9 Aspect Ratio". Within the folder are two separate mods. One with the regular OTC modified Telemeter Divisions (that has them broke down into fractions)......the other is the "Realistic Scopes" mod that has the Telemeter Divisions much like the authentic scope had. Only add one, or the other,......not both, to the main OTC mod.

To answer your last queston, the optional mod "OTC_1.4_Realistic Scopes" is only to be added to the main OTC mod correcting the 4:3 Aspect Ratio (if the Realistic Scope is what you want). The regular OTC scope view is already included within the main OTC mod.

Like HertogJan, you don't need to count the Telemeter Divisions and use the Omnimeter at all. It's your choice. The Stadimeter will work more accurately due to the corrections in Height measurements. The Omnimeter is just a back-up (as it was in real life). Although, I've often found the Omnimeter process is more accurate than the Stadimeter.

The "OTC 1.4 Patch 1" does more than correct the Deck Gun accuracy. Do you use the Anti Aircraft gun? I put exploding shells as a selection for both deck armaments. Kind of fun to "paint the sky" with them:

http://i175.photobucket.com/albums/w132/crawlee/Flack2_zps8bbd7b24.jpg

http://i175.photobucket.com/albums/w132/crawlee/Flack_zps02bca864.jpg

[Sniper297]

Hee-hee, as a former US Navy Aviation ASW Tech I came to two conclusions:
1. An aircraft is an excellent anti submarine platform. :ping:
2. A submarine is a really lousy anti aircraft platform. :dead:

For those reasons, I figure when an aircraft is in range I belong underwater where submarines do what they do best. :up:

Anyway I'll try deactivating and reactivating and using OTC_1.4_for 16 to 9 Aspect Ratio instead of OTC_1.4_Realistic Scopes for 16 to 9 Aspect Ratio.

Looking over the readme I apparently focused on "This will bring these views more in line to the real life division marks being dark in color. The scopes will retain their correct alignment of the Telemeter divisions; just darker in color." and somehow blipped right past "The Telemeter divisions will also have the fractional divisions removed". Senility. :88)

[banryu79]

As for "range doesn't matter", best I recall it was Beach who called it the "angle-off" method, where you guesstimate the speed, then lead the target by 10 to 15 degrees depending on the approximate speed. Set the fish for zero gyro angle, then set the crosshairs 10-15 degrees right or left (depending on target direction of travel) and fire when the target is in the crosshairs. If the lead angle is correct it's correct for any range, the problem is that at long range the target has more time to see the wakes and maneuver to avoid. I've used that method myself with manual targeting, but it's the same as auto targeting in that regard - closer is better, inside 1000 yards the target has less time to see and react, and the errors don't have as much distance to multiply.
Intresting, I didn't know about this "angle-off" method by Cmdr. Bleach.
However I can tell you that I successfully scored 2 hits out of 3 torpedoes fired against 2 different merchants (do not remeber the type, one had to be some kind of tanker) about 3,4-3,2 Km afar, in nighttime with clear weather conditions with my boat at PD.
And with straight shots (aka 0° gyro) done only with target speed, target course, ownship heading and torpedo speed data. No range at all until later, when plotting with the map tools on map contacts (at the time I was playing with map contact updates on) I found out the range I was from my targets when I fired the eels.
(I didn't know the precise speed, but according to map icons they were running at medium speed and I just guesstimated the true speed, after some observations on the attack scope, to be 8 kn).
[All of that in SH3 GWX3.0]

[Sniper297]

Beach, not bleach. Author of Run Silent Run Deep among other books, fiction and non fiction.

http://en.wikipedia.org/wiki/Edward_L._Beach_Jr.

At night that usually works simply because the target maintains a steady course if he doesn't see the wakes. Or if you're using electric Mark 18s which don't leave the big steamy trail of bubbles. Simple basic geometry, when two objects are on a collision course if neither one changes course or speed then sooner or later they will collide. Whether the range is 4000 yards or 500 yards the lead angle will be exactly the same, the practical difference is that the 500 yard range reduces the possibility that the target will change course or speed before impact.

Back on topic, reactivated and restarted, figured out how to get the omnimeter - grab the top edge of the message window and pull up. I'm clicking all over the omnimeter icon and getting nothing but a clicking noise from the mouse, guess I should study all the docs again. :doh:

One problem still remaining, the only button I can find says "identify target", I click on that and the message window automatically tells me what the target is. But still no recognition manual, so no way to get the mast height or length.

[CapnScurvy]

Pretty sure the "N" key brings up the Recognition Manual (same as stock).

As a matter of fact, the keyboard assignments are the same as stock in all respects (print off the Keyboard Assignments found in the stock game file "SH4_Q_Ref_Card_Front.jpg"), EXCEPT for the added Shift+X keyboard assignment ....which raises/lowers the Air Radar Antenna. This allows you to stay submerged, yet pushing up the SD Antenna to allow the Air Radar to function (only when you have the SD Radar available).

As far as the Omnimeter, there are two sliders that travel left/right..... click and drag the sliders.

[banryu79]

Beach, not bleach. Author of Run Silent Run Deep among other books, fiction and non fiction.

http://en.wikipedia.org/wiki/Edward_L._Beach_Jr.
.
Yes, I know, sorry for the annoying typo. I red RSRD about 10 months ago.

[banryu79]

But where I can find writings about that angle-off method? I don't remember to stumble upon it in RSRD...

[Sniper297]

Thanks, N key did the trick. I'm used to using the mouse to click on buttons, never played with the hot keys much. In fact this mod somehow disables the normal mouse wheel zoom, I had to stumble around for a while before I used the TAB key.

"annoying typo. I red" is that "read"? Blasted Otto Collect! :03:

I can't recall offhand where I "red" it, but RSRD actually had sequels, DUST ON THE SEA and COLD IS THE SEA, but it may have been in one of his non fiction books about his actual service. Method itself is fairly simple in game - play for a few weeks with auto targeting on, set up 1000-1500 yards off the track facing at 90 degrees, wait until the bottom TDC dial shows a zero gyro angle, and note the number of degrees the scope is offset. Depending on torpedo type / speed setting and the target speed it's going to vary, but in general merchants will have a lead angle (with the Mark 14 on high speed) of 10-12 degrees and warships 15-18 degrees, regardless of the range. Once you've made notes on the actual offset start a career with manual targeting. Set the scope straight ahead (minus key), crank the masthead height to max, hit the "Send range and bearing to TDC" for a zero gyro angle (leave AOB and speed set to zero). Move the scope the correct number of degrees right or left of center, start firing when the target enters the crosshairs.
"Kentucky windage" for snap shots, center the target in the scope and note the bearing, move the scope 10-30 degrees (depending on estimated speed and AOB) to lead the target, click the send button again and fire three or four fish on the same track spread 10 seconds apart.

I'm fiddling with this OTC mod simply to try out the scientific method, but for me the angle off / Kentucky windage method gets me a pretty high percentage of hits.