Stadimeter question

[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.

[razark]

Originally Posted by P_Funk

...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]

Originally Posted by 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

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

[CapnScurvy]

With Optical Targeting Correction 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.

Originally Posted by MCM

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, of 2007) quickly points out the problems the game has with measurements (least that's what Charos points out in the #8 reply):

Originally Posted by Charos

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"?