SUBSIM Radio Room Forums - View Single Post - Some curious confusions from a newbie....

Pisces · 12-22-12, 08:55 AM

@ Spirit X:

I'm not totally sure I understand your point. But I'll try to reply anyway to explain what you might be missing.

1: What you might be missing with the stock game, with regard to the Nav-map and targeting, is the cursor tool when drawing lines. (see 2nd and 3rd image in the Hunt tutorial.) Or a big plotting grid image replacing your Uboat icon on the map. ( ) I think these things weren't part of stock SH3. But they are very helpfull tools. Almost indispensible,... but I'm a mapdrawing-nerd. So I created this little mod to be able to point lines, waypoint legs, circle radi, and protractor legs in whichever compass-direction I want. I never used the big Uboat Icond replacing plotting grid as it was a major toll on my first computer. But I'm sure some versions of it are also in the Subsim Downloads section (like this, but it is old, and not completely JSGME-ready)

The manual and video tutorial in the academy teach you to use the Notemap targeting procedure. But luckily, you are not forced to do it that way. As this way, the important value that is needed for getting the torpedo on target (speed) is based on possibly inaccurate measurements (range) and guesstimations (AOB). Above all the fact that it needs the scope to be locked onto the target to get it right. There was no such things at the time, as an auto-locked periscope following the target.

One way is plotting the target's position on the map across a certain amount of time. For that you need range and bearings from the periscope, or from the Watch Officer (if he is up-top on the bridge). The bearings these provide are relative bearings though, measured from the bow and increasing to the right. To be able to plot them on the map you either locate the point inside the Uboat icon plotting grid. Or you first have to convert it to true bearing compass directions, before you plot this on the map (with i.e. my tools) from your current location. Like in The Hunt. The problem with this method is that you should do this while you are at a safe distance from the target. You do not want to be seen. As then they might fight back, or they start weaving their course. (But that won't help them much in the long run) If you have 2 or more plot points, spaced far enough apart in time and space, then you can measure the distance between them and calculate speed.

Another method to figure speed relies on knowing the length of a ship. So you need a pretty good ID. Or atleast so you don't have to choose between a short trawler and a large tanker. Using your Uboat's course and periscope you create an imaginary wall in the water, through which the target passes. You set this up by turning your bow or stern ('your butt') just infront of the target bow as it moves forward. You also set the periscope to 0 or 180 to look at it with it's vertical line: the imaginary wall. Make sure you have stopped turning before he passes the line with his bow. Now, no matter what your forward (or backward) speed is, as long as you are not turning, the target allways needs the same amount of time to drag itself through that 'wall'. You can do this from pretty much any angle, as long as you have a good view on it's bow and stern. If either is kept hidding behind structures then you have to guess the exact beginning or ending moment. You measure the time it takes it to does so, with for example the ingame stopwatch. Then divide the length of the target by the time, to get speed in meters per second. And then times 2, (as that is close enough for government work) gets you the speed in knots.

Figuring out the target course, or AOB when you look at it, can also be done by guesstimating. It's a fine art. Do-able, but it takes time, effort and opportunity to learn. And that ofcourse, needs being able to know the correct value to check it. They probably spend alot of time on this in the real world. So I guess it is the right way to do it. But I learned of another way.

I initially made this (well, I made the wheel, not the invention of the method) to be used to 'calculate' course based on 3 (crude) hydrophone bearings. It can be used with periscope bearings also, which are no doubt even more accurate. Well assuming your course is steady enough. Basically, you need to be stopped, or very slow. And take 3 bearings separated by 2 equal time periods. Then as you align the bearing differences up, the AOB at the 1st bearing shows up in the window. But this requires a significant amount of time between bearing to be realy usefull. The bearings slowly accellerate and slow down again as the target approaches and passes. This shows itself in a small divergence between 2 bearing differences. If the target is far away, this might require in the order of hours. But since you may not have visual contact, this is the only way to be able to tell where distant unseen contacts are going to. It's a way,... better than nothing imho.

There are also graphical methods that can be done on the map to do this. Search for 3 bearing, or 4 bearing hydrophone methods (which provides crude speed and distance also after you sprint away from your 3-bearing location). Like from a users named Nefelodam, Kuikueg or Mittelwaechter.

12-22-12, 08:55 AM	#12
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	@ Spirit X: I'm not totally sure I understand your point. But I'll try to reply anyway to explain what you might be missing. 1: What you might be missing with the stock game, with regard to the Nav-map and targeting, is the cursor tool when drawing lines. (see 2nd and 3rd image in the Hunt tutorial.) Or a big plotting grid image replacing your Uboat icon on the map. ( ) I think these things weren't part of stock SH3. But they are very helpfull tools. Almost indispensible,... but I'm a mapdrawing-nerd. So I created this little mod to be able to point lines, waypoint legs, circle radi, and protractor legs in whichever compass-direction I want. I never used the big Uboat Icond replacing plotting grid as it was a major toll on my first computer. But I'm sure some versions of it are also in the Subsim Downloads section (like this, but it is old, and not completely JSGME-ready) The manual and video tutorial in the academy teach you to use the Notemap targeting procedure. But luckily, you are not forced to do it that way. As this way, the important value that is needed for getting the torpedo on target (speed) is based on possibly inaccurate measurements (range) and guesstimations (AOB). Above all the fact that it needs the scope to be locked onto the target to get it right. There was no such things at the time, as an auto-locked periscope following the target. One way is plotting the target's position on the map across a certain amount of time. For that you need range and bearings from the periscope, or from the Watch Officer (if he is up-top on the bridge). The bearings these provide are relative bearings though, measured from the bow and increasing to the right. To be able to plot them on the map you either locate the point inside the Uboat icon plotting grid. Or you first have to convert it to true bearing compass directions, before you plot this on the map (with i.e. my tools) from your current location. Like in The Hunt. The problem with this method is that you should do this while you are at a safe distance from the target. You do not want to be seen. As then they might fight back, or they start weaving their course. (But that won't help them much in the long run) If you have 2 or more plot points, spaced far enough apart in time and space, then you can measure the distance between them and calculate speed. Another method to figure speed relies on knowing the length of a ship. So you need a pretty good ID. Or atleast so you don't have to choose between a short trawler and a large tanker. Using your Uboat's course and periscope you create an imaginary wall in the water, through which the target passes. You set this up by turning your bow or stern ('your butt') just infront of the target bow as it moves forward. You also set the periscope to 0 or 180 to look at it with it's vertical line: the imaginary wall. Make sure you have stopped turning before he passes the line with his bow. Now, no matter what your forward (or backward) speed is, as long as you are not turning, the target allways needs the same amount of time to drag itself through that 'wall'. You can do this from pretty much any angle, as long as you have a good view on it's bow and stern. If either is kept hidding behind structures then you have to guess the exact beginning or ending moment. You measure the time it takes it to does so, with for example the ingame stopwatch. Then divide the length of the target by the time, to get speed in meters per second. And then times 2, (as that is close enough for government work) gets you the speed in knots. Figuring out the target course, or AOB when you look at it, can also be done by guesstimating. It's a fine art. Do-able, but it takes time, effort and opportunity to learn. And that ofcourse, needs being able to know the correct value to check it. They probably spend alot of time on this in the real world. So I guess it is the right way to do it. But I learned of another way. I initially made this (well, I made the wheel, not the invention of the method) to be used to 'calculate' course based on 3 (crude) hydrophone bearings. It can be used with periscope bearings also, which are no doubt even more accurate. Well assuming your course is steady enough. Basically, you need to be stopped, or very slow. And take 3 bearings separated by 2 equal time periods. Then as you align the bearing differences up, the AOB at the 1st bearing shows up in the window. But this requires a significant amount of time between bearing to be realy usefull. The bearings slowly accellerate and slow down again as the target approaches and passes. This shows itself in a small divergence between 2 bearing differences. If the target is far away, this might require in the order of hours. But since you may not have visual contact, this is the only way to be able to tell where distant unseen contacts are going to. It's a way,... better than nothing imho. There are also graphical methods that can be done on the map to do this. Search for 3 bearing, or 4 bearing hydrophone methods (which provides crude speed and distance also after you sprint away from your 3-bearing location). Like from a users named Nefelodam, Kuikueg or Mittelwaechter.