How does the stadimeter work ?

[Amiral Crapaud]

Anyone knows if there is any reason for this tricky "ghost ship"? Why did they need the "ghost" for? They couldn't use a simple line like the German apparently had if I refer to SH3?

All this "ghost" stuff makes stadimeter work a little bit blurry and harder...

[John Channing]

The german Fire Control proceess did not acually work as it is represented in the game. It was simpliifed for gameplay purposes.

The SHIV Stadimeter is an accurate representation of that part of the US TDC.

It operates on simple tigonometry. If you know the actual height of the mast, and you know the appearance of how high it is from your point of view, the distance to the target is relatively simple to figure out.

JCC

[Joe S]

I havent tried it but my understanding is you can use any part of the target for which you know the height. The origianal recognition manuals show the height of the funnel which may be easier to use than the mast because its easier to see in poor visibility. If I can ever run SHIV without crashes long enough to test it I will do so. Joe S

[ReallyDedPoet]

Welcome to SUBSIM Nissum


RDP

[Nissum]

Hello

Have just seen your Uberboot video on youtube. Now thats what i call firepower.

Nissum

[Hitman]

In SH4 you can also set manually the wished heigth in the circular dial by dragging the transparent triangle and not use the recognition manual at all. I do it a lot to estimate distance based on funnels, bridge and kingposts instead of using mast The heigth of those parts I calculate using rules of thumb: 8 feet for each deck, then use the decks as yardstick to approach the bridge or funnel heigth. Works usually well

[Rockin Robbins]

Originally Posted by Hitman

In SH4 you can also set manually the wished heigth in the circular dial by dragging the transparent triangle and not use the recognition manual at all. I do it a lot to estimate distance based on funnels, bridge and kingposts instead of using mast The heigth of those parts I calculate using rules of thumb: 8 feet for each deck, then use the decks as yardstick to approach the bridge or funnel heigth. Works usually well

Awesome. Without Subsim, I never would have learned that!

[don1reed]

Originally Posted by Alain-James

Anyone knows if there is any reason for this tricky "ghost ship"? Why did they need the "ghost" for? They couldn't use a simple line like the German apparently had if I refer to SH3?

All this "ghost" stuff makes stadimeter work a little bit blurry and harder...

The reason for the stadiameter is to be able to keep the target in view and get a range reading EVEN during foul weather, when the sub is bouncing around.

If you want to use manual trig to figure range from vertical tic marks during calm weather thats almost just as good; but, the prism in the kollmorgen scope allows for split-image range finding just like the surface ships have, only addaptive for a small objective lens such as the scope.

[Powerthighs]

If you are getting the targets course easy enough just keep adjusting the AOB until the targets course indicates what you calculated on the upper dial of the PK.

To expand on this, as you adjust the AOB to various values (and click the "send" button to the TDC each time), you will see the top ship on the TDC rotate. The outer ring respresents the target ship's true course, as pointed to by the bow of the ship on the inner ring. If you know the target ship's course, you can simply adjust the AOB until the 0 point at the bow of the ship on the inner ring is aligned with the ships true course on the outer ring.

AOB and true course of the target are really the same information. The difference is that the true course is relative to a compass, while the AOB is relative to the true course of your sub. Since you know the true course of your sub at all times, knowing one is as good as knowing the other.

[Nissum]

Returning to the stadimeter. It is very difficult to use the stadimeter at long range becourse i cannot see the top of the mast. When i think the stadimeter is in the right position it tells me that is is aprox 8000 to target. When i mssure it in my navigation chart ther is just about 6800 meters, so here is my question. Does the stadimeter show the range in meters or in yards ?.

Nissum

PS. anybody know of a mood that makes you zoom more than x 6 in the scope?

[don1reed]

Table 8. in Bowditch tells us that the distance to the horizon is 1.144 x sqrt of height of our eye above sea level.

Then: if scope is 3 feet ASL, distance to horizon = 1.9815 nm (4014.5 yds.) (see graphic below)

As you can see, in my example, the target ship will be "hull-down". The curveature of the earth prevents us from observing the full height of the target and therefore prevents us from getting an accurate Range to the Target.

This means that we must wait to get visual range measurement on our target. If there are no DDs in the vicinity, we can PING for range or use radar.

The distance to horizon depends on the height of our eye when making the observation.