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Old 02-22-13, 08:22 AM   #33
Maggoty
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Join Date: May 2012
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Quote:
Originally Posted by Carrollsue View Post
Will, kind of…. I have a tube with mirror and lens of a know length, so you can get two image’s and when you superimpose them on a calibrated system you find distance and you can find height doing that to, just different technique. Now with that , I'm not the a good math person, but if I know the height of something and using a machine that will give me the angle between that height and the straight line to the target that I’m looking at it( not sure if it cos or sin), I can find the length to it. using Trig
Quote:
Originally Posted by twm47099 View Post
The method in the game, matching the WL with the top of the mast, was how it was done. There are a couple of WW2 periscopes in the Washington Navy Yard Navy Museum. There is a sliding plate at the eyepiece that moves up and down when you turn the range knob. One image moves. The double image (put base of one at top of the other) is not as easy to use as a camera range finder (although that could be due to degradation of old optics), but it was designed to work at much longer distances and without a long enough range finder baseline.

This is a link to the 1946 periscope manual. One thing I found interesting is that the stadimeter (at least in 1946) could be rotated 90 degrees to be able to use ship length as well as mast or funnel height.
http://www.hnsa.org/doc/fleetsub/pscope/chap4c.htm#4J

In "Run Silent Run Deep" there are a few descriptions of attack approaches where the range is estimated using the stadimeter. In a couple of long range early estimates the captain estimates the height of the mast above the deck (not WL) and uses that as his reference height. As the range shortens he improves the range estimates.

Tom
Quote:
Originally Posted by CapnScurvy View Post
Yep, that's how it was done. I too have read how the stadimeter could be moved both vertically and horizontally depending on your desire to calculate for either range or angle on bow. The vertical placement measured height, the horizontal placement measured length......both measurements were compared to what the "known" estimated measurements should be. A tool like the Range Omnimeter was used to help in calculating the difference between the two (so was a quick mathematician on the firing party). The estimated range came from the height calculation, the AoB of the target came from the length measurement difference.

The stock game needs to be corrected for several things before a good manual firing solution can be gleaned. The mast heights need to be corrected; the Field of View needs to be corrected allowing the scopes Telemeter Divisions to be used for measurement. For instance, when the game was first released the jap CV Hiryu had a mast height of 20 meters (65.6 feet). After a lot of gnashing of teeth, the Developers changed some of the worst offenders (as memory serves me, it was with their 1.4 patch), however their new mast height for the Hiryu is still off the mark by about 6 meters. One of the things you'll run into is some mods don't pay a bit of attention to this type of thing. Take TMO 2.5 and check the Recognition Manual for the Hiryu. The mast height is back to the original figure of 20 meters. To read an accurate stadimeter measurement it should read about 37 meters (121.4 feet). The difference in the height will throw off a stadimeter reading by about half the range it should read.

It's too bad the game limit's us to only using the stadimeter for range finding with the vertical process. Believe me, if there were a way to make the stadimeter work as the real thing I'd of done it. But the stadimeter is "hard coded" in the game (much like the math formula it uses to determine the stadimeters reading), there's nothing we can do about its short comings.

One thing I know we could do is make the Recognition Manual list more than one height measurement. Allowing a player to choose which particular spot on the target you wish to use when matching the stadimeter water line to it. You'd have to have a better way of telling the TDC/Position Keeper what height to use when you do the stadimeter second image, but for a long time I've considered doing it. The first part of the issue is done with the correction of the Field of View to the measuring device (the scopes view) with Optical Targeting Correction. What's left is to take each target ship and measure to the various spots on the ship (the ships funnel, the top of the bridge, the ships deck), put those measurements into the RM, then make a dial for the ships particular height that's used by the stadimeter and make a range estimate using that particular spot. If you can't see the mast top, use the targets funnel instead. Just something I've had in the back of my mind for a while now.
Well shoot that's pretty cool, I figured the real life version used a split image I just didn't know how close the game was or was not to reality. Thanks for the info guys it's kind of cool learning this stuff. Scruvy I do hope you find a way to do the selector switch, those masts at more than a couple thousand yards are killer.
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