Authentic method of getting firing solution?

[Tom]

Ok, this is the first thread I start... so sorry if I'm asking something that's already been discussed here.

I've recently started doing my targetting manually with no map updates, using watch officer estimates for target range when overhauling and periscope range finding when closing in, and plotting the solutions on the navigation map. What I would like to know is the authentic method used by the germans to turn target range/bearing/time information into target AOB/speed. (The Submarine Commander's Handbook calls for "estimation of range and position at regular intervals of time", but doesn't (or I just somehow missed it) explain the preferred method of calculating AOB/speed from these.)

They obviously didn't have a navigation map displaying the exact location of the submarine at all times, but they could have plotted the submarine's movement based on course and speed, together with the target bearings/ranges/times, and use this information to plot the course and speed of the target much like I do it on the navigation map now. But is this how it was done?

Furthermore, how did they estimate the firing solution in cases where observations over a longer time weren't available? (Bad weather, target changed course moments before attack, etc.)

Using search I found several threads explaining working methods for manual targeting, but couldn't find out which was the actual method used. If I just missed the information, could someone please point me to the thread?

[Puster Bill]

They used one of these:





Which you can download, print out, assemble, and find the directions for it's use in this thread:
http://www.subsim.com/radioroom/showthread.php?t=114351

Alternatively, you could use a regular linear or circular slide rule if you have one handy, as long as it has an 'S' scale on it. The thread that explains that one is here:
http://www.subsim.com/radioroom/showthread.php?t=112765

This is also a helpful document, even though it applies to the American Submarine Attack Course Finder/IS-WAS:
http://www.hnsa.org/doc/attackfinder/index.htm

[Tom]

Thank you very much. I recall seeing some of those threads, but somehow missed them when trying to search for them yesterday.

Those of you who use a wheel like that: what are your experiences regarding accuracy and ease of use? My intuition would be that a wheel is easier to use than plotting solutions on map, atleast once you get the hang of it. As for accuracy, when plotting on map it easy to refine the solution when you get more observations. How do you do this with the wheel (which, if I understand it correctly, gives the solution based on two observations only)?

Ah, well, I guess I'll just have to build one and try it out myself.

Originally Posted by Tom

Those of you who use a wheel like that: what are your experiences regarding accuracy and ease of use? My intuition would be that a wheel is easier to use than plotting solutions on map, atleast once you get the hang of it. As for accuracy, when plotting on map it easy to refine the solution when you get more observations. How do you do this with the wheel (which, if I understand it correctly, gives the solution based on two observations only)?

I was thinking about building the wheel but gave it up for now. I was doing some serious plotting but now nearly I don't draw more than a single line - a general course if I need to follow. It all started when I removed my position from the map (as to use celestial navigation). Suddenly I have found myself calculating in my head bearing, speed, course etc. I started to see things differently, started to fell relative courses etc. Another thing is that to be realistic you need to make some observations like timed hydro readings, manual range through your scope etc. The more you spend on the see the more it's obvious and very quickly you just know what to do, how to react. This gives a very nice feeling of being a true, trained and experienced captain who has everything in his head!!

[Tom]

Originally Posted by Hadrys

I was thinking about building the wheel but gave it up for now. I was doing some serious plotting but now nearly I don't draw more than a single line - a general course if I need to follow. It all started when I removed my position from the map (as to use celestial navigation). Suddenly I have found myself calculating in my head bearing, speed, course etc. I started to see things differently, started to fell relative courses etc. Another thing is that to be realistic you need to make some observations like timed hydro readings, manual range through your scope etc. The more you spend on the see the more it's obvious and very quickly you just know what to do, how to react. This gives a very nice feeling of being a true, trained and experienced captain who has everything in his head!!

My problem is finding enjoyable balance in the game. First I used map contact updates and weapon officer assistance. Soon practically every torpedo I fired hit. Then I turned off weapon officer assistance and used the updating map contacts to plot tracks and generate solutions. Nothing changed, practically every torpedo hit. Recently I turned off map contacts and started plotting manually based on observations. Now I miss about 10% of the time, with something like 50% of my torpedoes hitting within 5-10 meters of point of aim.

The only thing that has changed as I've turned on more realism, is that I now only fire from good positions. No more instant weapon officer solutions against zigzagging targets in poor positions. Also, gameplay has become a lot slower - plotting takes time.

I'm not ready to go through the trouble of navigating myself. That would slow gameplay even more. With my current settings I already find the game a bit too tedious to my liking. A real captain would have had crew to do some of these tasks. Unfortunately the game crew is too good at its jobs, making hitting targets too easy for the game to be enjoyable.

So I'm looking for a method of playing the game without making tedious observations and plotting, being able to hit about realistically, and not using the way too accurate crew observations, if at all possible. Good suggestions are welcome.

One solution I'm currently considering, and will test out next, is this:
- Overhauling the target on surface, keeping a long range and a general bearing of 90 or 270 to target. This should give me an idea of target heading as I visually observe aob changing during the maneuver, as well as some idea of target speed.
- Submerged approach on a (as close as I can visually determine) perpendicular course, setting speed, when possible, so that the bearing to target keeps constant. This gives me a good idea of target speed and puts me in a good firing position. I can also stop and measure target speed quite accurately using the stopwatch and target length, if I am in doubt.
- Visually verifying aob and measuring range through the scope, and adjusting the TDC accordingly, just before firing.

I'll have to see how this works out. I just fear that I'll end up with worse solutions than a real captain would have in a similar situation, and won't be able to hit much anything. Hopefully I'm wrong about this.

[joegrundman]

The wheels are great! Transforms your game. You never need to waste time on plotting to get course again. Unless visibility is extremely poor, I find I often don't draw anything on the map at all, although this does depend on what it is I'm hunting.

The fact is that in RL neither the GErmans or Americans wasted their time using bearing plots -just too inaccurate. There are far more effetcive ways of doing it (although I still will do the 3 min 15 sec thing occasionally, if the situation calls for it, for example if I'm already sure of course and I'm just lying in wait, it's an easy way to confirm your earlier estimates)

As for finding manual plotting a bit too slow...well, that changes soon. The challenges never really stop too. With plotting etc you can get into position and make an easy kill some of the time. There are lots of contacts you will be unable to catch that way. A big part of the joy of this game is the discovery of new ways to get those targets you used to just give up on.

[Hitman]

Now you got me started LOL

Here is a preview of what I'm actually working on....

This is an adaptation of the real item the U-Boots had attached to their periscope around the eyepiece (Rough eyepiece drawn in the center of the wheel below). In real U-Boots, the wheel had less scales, but since I inted to use it in SH3 I needed an extra one to show what was automatically moved in the scope when the captain adjusted the split images.

Basically, the procedure was as follows:

1.- Get range, like it is done in SH3 (Mast heigth known or estimated)
2.- Turn the eyepiece 90º (Yes it was rotational!) and set the distance you got from the first step in the middle wheel (Entfernung) to align with the known or estimated length of the enemy vessel in the outer wheel (Basis). In this case we have a 200 metres long ship at 950 metres distance
3.- Now using the split images horizontally instead of vertically (Like he did when the mast was measured), the captain aligned bow of one image with stern of the other, and the handle he moved to do that is mechanically connected to the inner dial (Kurswinkel) of the wiz-wheel, which rotated proportionally as much as the split image was moved. So it indicated the AOB of the target in a certain mark (Opposite the 100 mark of the outer wheel), in our case below, the AOB is 90º.

------------------------------------------------------------------

Now for SH3 I had to add a new scale between distance and AOB because we don't have a system of horizontal split images. So I had to work with a fixed inner ring and the new scale displays the scope horizontal marks. In this case, the AOB of 90º is almost 13 scope marks at the low power zoom (The one used at U-Boots for measuring this all), so if you see for example that the target extends only 8 marks, you see opposite that value in the scope marks scale an AOB of 40º in the Kurswinkel wheel.

I have this already finsihed for external print & build a wiz-wheel, but I would really really love to be able to implement it inside SH3, in the scope screen (The UZO used another method). Would be amazing stuff to use in-game!

[Wilcke]

Simply awesome, just astonishing.

Wilcke

I've always believed in german technology but this is awsome! How precise and complicated had to be those things!?

It also boosts my realism feeling cause I wondered from time to time why 95% or more of my eels hit. Now I know that this was simply so accurate and if doing it right you couldn't miss. Wow!

Impressive work, can't wait for the full version of your Bible!

[Tom]

So, this is what happened:

Captain identifies ship, and checks mast height and ship length from manual, or estimates them. He then turns a couple of dials on the periscope, matching two pictures, and has range and AOB.

All he needs in addition to this is speed. And that could be measured exactly using any of the following (and probably by some other means too):

- Matching course and speed when doing long range approach, even before identifying ship.
- By keeping a constant bearing during perpendicular submerged approach. (Or at any other angle, but this would require a bit more calculation).
- From any two timed spottings with some trigonometry.
- Using the stopwatch to measure speed from stationary sub at any time after ship was identified and length known.

The Submarine Commander's Handbook suggests that measuring range was the only somewhat difficult part (which is quite true at least in the game through the periscope/uzo). An error in the range estimate would also mean an error in AOB. But AOB could be visually checked, to make sure there is no large error. (And if there was, the range could then be rechecked.)

This is very impressive. I'm tempted to turn weapon officer assistance back on. Or perhaps a good (giving realistic effects) solution would be to use the AOB given by the weapon officer together with my own speed and range measurements (both done from the periscope/uzo).

Thank you very much for all the information, Hitman.

[Hitman]

Now I know that this was simply so accurate and if doing it right you couldn't miss. Wow!

Well, not that easy, and certainly there were many errors, but the german success laid most in that they fired very close (Less than 1000 metres if possible, better 500). Mast heigth and ship length is not so easy to estimate if you don't know for sure the values, but since U-Boot commanders were after all people experinced at sea (Some came from the merchant Navy like Prien or Schulz) they tended to make good estimates.

Also many times they fired at a ship but actually hit another (The advantage of shooting at convoys), something that actually happened a lot to Kretschmer

Captain identifies ship, and checks mast height and ship length from manual, or estimates them. He then turns a couple of dials on the periscope, matching two pictures, and has range and AOB.

All he needs in addition to this is speed. And that could be measured exactly using any of the following (and probably by some other means too):

- Matching course and speed when doing long range approach, even before identifying ship.
- By keeping a constant bearing during perpendicular submerged approach. (Or at any other angle, but this would require a bit more calculation).
- From any two timed spottings with some trigonometry.
- Using the stopwatch to measure speed from stationary sub at any time after ship was identified and length known.

The Submarine Commander's Handbook suggests that measuring range was the only somewhat difficult part (which is quite true at least in the game through the periscope/uzo). An error in the range estimate would also mean an error in AOB. But AOB could be visually checked, to make sure there is no large error. (And if there was, the range could then be rechecked.)

Yes, that's more or less how it was done