How to plot,get range,speed,all with map updates off

[Hitman]

I think the main reason I am concerned is basically it will force me to use the stadimeter,which I never use as it is far too inaccurate for my liking.

I did this little job for SH4: http://www.subsim.com/radioroom/show...hlight=plotter

The mod itself will not work with SH3, but the idea certainly will. Take a look at the PDF with the tutorial, the most important idea from it you must get is that your must AVERAGE the enemy positions you have marked on the map. That's how it also worked in real life, because the real life stadimeter also wasn't accurate.

In any case, be aware that this isn't the only method to get the target's values for your firing solution. You can use fixed wire method for speed and eyeballing for the AOB (Both also used in real life).

Good hunting

[Paul Riley]

Thanks a lot.I will read that very soon
I just need to try and get those bloody youtube videos working

[Paul Riley]

Originally Posted by Hitman

You can use fixed wire method for speed
Good hunting

I am surprised,I never knew about fixed wire method,what is this exactly?.

[Paul Riley]

Hitman,I seem to be having a lot of problems viewing some of these links,esp. at Filefront.
Do you have a link to any old posts in this forum,that may describe a lot of what i'm after?.

Cheers.

[Paul Riley]

Say,do I actually need to subscribe to youtube to view their videos?.I mean,I practically never go to youtube,i've never had a reason to,until now possibly

[Paul Riley]

Thanks hitman and pisces.

Just give me a moment,I have about 10 bloody webpages open at once here!

[Pisces]

Originally Posted by Paul Riley

I am surprised,I never knew about fixed wire method,what is this exactly?.

You set your periscope forwards or to the rear, and set your course until the view is right infront of the targets bow. Start your clock when the bow touches. Stop it again as the stern (backside) leaves the line. The ship's overall length, divided by this time is the speed of the target in meters/second (or whatever units used). The value in knots is almost twice this m/s value. Basically you have just made an imaginary stationary wall through the water with your periscope line. The periscope must be along your bow/stern centerline to nullify the distorting effect of your own speed you would get if the scope is looking sideways. But if you know your speed well enough it is 'rather easy' (with Hitman's Attackdisk, ISWASWHAT-EVER , slideruler) to calculate the speed correction based on viewing direction.

Real uboats had a moving line in the scope optics that was slaved to the gyrocompass. So any small course deviations of the uboat would have been cancelled out. We need to make sure we don't turn, by keeping the rudder amidships, or submerge to soften the wave ridding. They called it 'feste Linie im Raum', translated to 'fixed line through space'

[Paul Riley]

That is an interesting method pisces,I may practice this out in the academy later.

You mention an 'imaginary wall' through the water,in order for me to understand this concept would it be similar to an athlete as he crosses the finish line,or a horse?.You are timing him a few lengths backwards and then again as he actually crosses it?.

This method could come in handy if you are bang at 90deg to your target,as you could then accelerate ahead until he is about 130deg behind you,swing the boat round 90deg until you are perpendicular and get ready to time him? (nice).
It doesnt however sound very handy if you are miles behind your target,and you need a faster speed estimate,so you can get things rolling quicker,like your intercept run.

What do you think to the method where you draw level,and alter your own speed until you are both constant with each other?this to me sounds about the most accurate method for getting speed calculations.I would probably monitor him for about 5 mins for me to feel confident I have him.This method is also great when you have already crippled a ship or he changing course after a previous attack,and you quickly want to set up a second or finishing blow.

Good stuff mate

[Paul Riley]

That last post pretty much gets the speed part out of the way.Now with map updates off it is going to be far more difficult to get accurate plots so you can get his mean course.I think the best thing to do,at least for me at the moment,is not to forget the four main compass points,to get a quick bearing on his direction.So,if I was going west,and I spot a ship going left to right roughly,I would swing the boat round to the north,this is logical.At this point I need accurate observations on his true direction,which is quite difficult.If it looks like his bow is facing slightly away from me I would likewise turn my boat say,10deg towards him,and repeat until his beam is about level with mine.Does this sound a good method,for getting his mean course that is?

Next,if I have his course,I could then extend his course on the map in front of him and do the same from my U-Boat,and then measure the distance between both lines,this then would be a good value for range?

I get the feeling that playing without map updates on forces the player to use his own judgement more,using visual cues all around him,which as a matter of fact does sound far more realistic,as the real captains would have had a lot of trial and error to contend with,not to mention the possibility of visual distortions.I think what i'm trying to say is,it would develop a keen sense of spatial awareness.

(getting quite excited at the possibility of improving my already decent skills at the game)

[Paul Riley]

Well,i've just spent the last hour or so in the academy,refining my skills without the map updates,and to be honest with you I found myself looking less at the map trying to mark points,lines etc,and more on what was actually happening 'out there'.This I think is perfectly normal,and proves that what is happening is you're relying on your own two eyes instead of technical accuracies/inaccuracies on the map as the case may be.
Against the C3 cargo in the torpedo training,I already knew from previous training sessions that he is on a mean course of 70deg.I first set course for east,at full,and carefully watched his bow,and it was still pointing away to the north,so,I pointed the uboat 10deg towards him,and kept doing this until his beam was roughly level with my beam,alas,at approx 70deg.I slowed down as he came close to the 270 mark,and altered my speed until we were about constant.He was observed at doing 3kts.I set the 2 torp spread (0.2 spread) to 3.5kts,and a depth of about 5m.
I used the stadimeter to get a basic range to him,it read 1600m,so I set the torp range to 1500-2000m.I don't think range is that important is it?,after all,it just determines how far it will travel?.
I fired the spread when at 270 and watched what was probably my best shot I have ever done in the game,they both slammed into his fore section,and tore his bow completely off.He sank like a brick.

The next section describes how I engaged one of the merchants further out to the north.I have found that in order to get a good fix on his course I turned the uboat so that the scope read 0 at his position,this then was the base for the course estimate.I have observed that the ideal angle from this point to draw parallel to a target and at a good range is about 30deg,so from the zero point I swung the boat round until he read 330.I steamed ahead at flank,until he was drawing ever more level.I kept watching his beam and when he closed to 270 again,his beam was practically aligned with mine.He was observed at doing 5kts using the earlier method,and again,because they are liable to speed up quite a bit as a torp closes on them,I set 1 mag torp to 5.5kts.The result was very reassuring,it slammed into his foresection,and he plummeted down bow first instantly.

Let me know what you think to the above methods,and not one attack was made or plotted on the map,it was all down via visual cues,and watching the target closely in relation to me.
Were these methods used in real uboats?.They are very successful methods I think.

The only problem I will have I think,is when it comes to convoys with strong radar,as making actual observations like these will be very hard,as most of the time you have to keep out of their radar range
Naturally,to combat this I think being able to plot using the hydrophones is essential,beyond visual range I mean ...so be it

[Paul Riley]

By the way,thanks pisces
This has been quite an enlightenment

[Pisces]

It's too late for me to completely picture what you did there. But I can explain the range factor. Range is needed as a hidden input to the speed measurement with the notepad procedure at the attackscope. If that is wrong speed is also wrong by the same proportion. But if you measure speed by some other means (like that fixed wire method) range is only a factor as an aiming correction when the torpedo has to turn. When firing straight out of the tube the torpedo doesn't turn and range is no factor at all. (hmm, maybe the torpedo run time on the stopwatch is wrong, but all other things being correct it should still hit where intended.) If the torpedo has to turn (because you want to hit something more to the side of your uboat) it first moves a certain distance straight ahead before it moves in a circle-arc. This straight and circle move causes a slight parallax angle to the direction of the periscope. The torpedo needs to turn a bit further. This parallax angle becomes bigger with bearings away from bow and stern upto a maximum at 90/270. And is also larger at a close range, but then the target looks bigger, so it may not matter.

But here's a question that often puzzles me. If you (manual targeting players in general) want to train or test yourself in hitting something accurately from a distance, why do you fire with a shotgun (salvo angle)? It covers up any mistakes made as you are more likely to hit anyway. Ask yourself questions like; if it passed infront or aft of the intended location (speed or AOB wrong). Did it hit too early or too late (range wrong)?

[Pisces]

Originally Posted by Paul Riley

That is an interesting method pisces,I may practice this out in the academy later.

You mention an 'imaginary wall' through the water,in order for me to understand this concept would it be similar to an athlete as he crosses the finish line,or a horse?.You are timing him a few lengths backwards and then again as he actually crosses it?.

This method could come in handy if you are bang at 90deg to your target,as you could then accelerate ahead until he is about 130deg behind you,swing the boat round 90deg until you are perpendicular and get ready to time him? (nice).
It doesnt however sound very handy if you are miles behind your target,and you need a faster speed estimate,so you can get things rolling quicker,like your intercept run.

What do you think to the method where you draw level,and alter your own speed until you are both constant with each other?this to me sounds about the most accurate method for getting speed calculations.I would probably monitor him for about 5 mins for me to feel confident I have him.This method is also great when you have already crippled a ship or he changing course after a previous attack,and you quickly want to set up a second or finishing blow.

Good stuff mate

A finish line is a close analogy. However, in sports it is usually the interest to determine when the athlete crosses the line. Not how fast he moves when he crosses the line. I don't know why they use multiple measurement locations at finish-lines, perhaps to sort out who is first and who is second or third. But luckily we don't have that problem.

During the whole process of fixed-line speed measurement the uboat only moves towards or away from the target (along this wall), if at all. We have just one finish line being the scope line. The multiple lengths you speak of is just only one, being the actual length of the target (thus requiring identification and so ofcourse an accurate recognitionmanual). If you think of the shiplength as the tracklength, and the intersection of the stationary wall with the ship as the athlete, and the time span of move between bow and stern as start to finish, the finish-line analogy holds.

Your leveling method works if you know his course reasonably well. Otherwise it is difficult to tell if you are both on eachothers beam (90/270 degrees bearing). Visual determination of 90 AOB is a tricky subject. The above fixed-line method is less sensitive to unknown course. It works best between 30 and 150 degrees AOB, but theoretically with all degrees AOB. The problem with very small or very large AOB is that the structures prevent seeing the bow or stern. And a wide ship might show it's side passing the line before the bow-point does.

I do use a variation of your leveling method often when measuring the speed of a target I intercepted. I take the location of the map contact report as the start. And wait until it passes a line (periscope or hydrophone bearing converted to compass direction) that is perpendicular to the reported course. This line may not be completely perpendicular to the actual targetcourse (+-11 degrees) , but the time since it's start is long enough to make it insignificant.