Yeah, I know. I was just thinking about that. Creepy, huh? :up:

Now we're going well beyond techniques used in WWII submarines. I would prefer not to use anything that cannot be plausibly shown to have been in use then. Granted, given the knowledge they could have used the techniques, but I personally draw the line a little closer to actual practices.

Those are incredibly interesting though!

I think I do better guessing..............

Yeah, but keep in mind, I'm workin on an app that isn't necessarily related to WWII tech anyway. Of course, you wouldn't have to use it, but it might be fun to make it work.

I wish I could just work on my apps full time, but I guess I gotta earn a living too...

With that in mind, my method of Course/AOB determination.

Visual AOB come with a bit of practise, and in the beginning one can guess within 20 Degs accuracy, this coming down to easily within 5 degrees with experience.

You want to put your sub at 90 Degrees to this course, so you must turn you sub on a course so that

Scope bearing = 90 - AOB (for Front tubes - STB side)
Scope bearing = 270 + AOB (for Front tubes - PORT side)

Scope bearing = 90 + AOB (for Rear tubes - STB side)
Scope bearing = 270 - AOB (for Rear tubes - STB side)

Now
Ship course = NEW Sub course + 90 (ship travelling from PORT to STB)
Ship course = NEW Sub course - 90 (ship travelling from STB to PORT)

To summarise:
With the sub travelling on any course:

For AOB < 90
Ship course = Sub course + Scope Bearing + (180 - AOB)

For AOB >= 90
Ship course = Sub course + Scope Bearing + (AOB - 180)

For answers > 359, just subtract 360 until your answer is <= 359

Just pulled this formula out of the hat - Preliminary checks look OK
:D

In my holidays I had some time to think about the relationship between a ship's AoB and it's own course.
The formula that came up in my head looked just like yours. At least for the upper one I remember it like this. It puzzled me a bit how relatively complex it looks, I would have expected it to be more simple.

But this is why those AoB-Wheels are such handy little things, I guess :DL

Yep, every course/bearing numbers we use are modulo 360.

It's a valid point. I have no indications that it (my tool) was used during WW2 on either side of the globe. But I also do not feel the need to replicate exactly the procedures and practitions of those days. For me it is enough if the technique isn't beyond their technical means (like it being made as a slideruler instead of requiring digital computation, or requiring uber-fine bearing resolution).

Use whatever feels right in the end.

Lots of interesting comments in here. I'll have to look into that MoBo mod.

Like I said at the start, I'm not sure how practical this is. I still haven't had the time to shoot at something with it. I'm a terrible skip and bad shot so me shooting at something might not be the best way to prove or disprove anything in any case, lol

I admit this isn't very realistic in the sense that initial contact was probably not usually obtained through hydrophones but rather radar or visual in which case, you already have a good bit more data than we have to start this exercise.

All the running around that you'd have to do (to establish contact, firm it up, close the range, and attack) would also likely be a large drain on your boat's batteries - at some point after first contact, you're going to want to stick your scope up, and if your target's not in visual, go to surface for an end-around, at which time you might be able to establish a radar fix on the target.

So all in all, this is probably more of a thought exercise than anything. I'll still have to try to sink something this way though.

Re: the comment on relative vs. true heading, yeah, your boat would be stationary in the initial timed bearings. This is already unrealistic since we know it was hard to hold depth at a stop. Vector addition sounds scary though.

Re: the comments on how to time the bearings - you're right, and as I said, you'll want to use whichever time interval gives you a good separation on your bearings. If you're starting with three minutes, and in three minutes your bearing on target has hardly budged, it might be a good idea to wait five or more - just be careful the contact doesn't wander out of range and you have to chase him down again. :) I just used the three minutes because of the easy conversion (and initially, because it's the interval RR used in the sonar only attack vid).

EDIT: Also, Pisces, thanks for those links. I'll have to read up.

Not put anyone down but without taking some scope peeks from time to time using this method arent you pretty much making yourself do a buch of of math to take a guess that you could just guess without the math?:hmmm:
Sorry I just have never loved math much if a man came up to me and said "give the square root of .646564564 or i will shot you" Id turn and run as fast as I could.:har: Sort of sounds like you are trying to dod what can be done in a modern sub without the stuff to really do it. i guess if you dont mind math and you want to add that to messing with formulas it could be fun :doh:

The use of 'math' and formula's is very overrated. No square roots or thick sine/cosine formulas are needed (I've done the work for you). It can all be done by drawing lines on the map. (granted, technically that is also a form of math: geometry) And if you use my tool you can avoid constructing the AOB/course line using geometric techniques. (also less drawing inaccuracies build up) There is a formula behind it, but you don't need to know what it is to use it. At the most you would need to be able to figure out speed-distance-time problems. (not for my tool, but for the other steps RingoCalamity showed) The nomograph-mods are already a common tool for that, which is also based on funky math btw.

I suppose you could make a guess as to what the probable course is of the target, IF you can see it. But you're gonna have alot more issues if you can't see him yet. To wait before it get's there is too much of a waste of time, imho. And it might not even happen. You could also just home in onto the bearing on the surface and regularly check on the hydrophone if the (true)bearing moved as you attempt to close on him. You could also do it submerged, but that is a heavy drain on the batteries, that you might need later. And this frequent surfacing/diving is, I would guess, also a heavy strain on the crew and sub equiptment (in real-life). Too much wear-and-tear in the long run. Eventually you should come into visual range and your visual AOB guess make it more simple. But, in response to what someone above said: I'd like to leave the guessing to the target, instead of me. Also, since I play Sh3 exclusively, it is important not to rely on visual information as Allied radar is going to get me in the end. I would like to know what he is doing wel before the target (or his protection) is in the position to harm me. That means several 10s of kilometers (or whatever it is in nm for SH4) away.

:up:

If the contact happends to allready have an AOB beyond 90 degrees at the time you first hear him then it is indeed not possible to tell (during those 3 bearings) how long he stays in your sensor range. That's why I suggest a minimal 1st bearing interval of around 6 to 7 degrees worth of time to determine a rough AOB value (upto about 160-170 degrees at which point it is wise you let the contact go). The minimum of 5 degrees on my tool prevents you from ever getting AOB beyond 90 degrees, because the bearing differences get smaller as ships move away. And there are no marks less than 10 degrees for the full 2-interval bearing drift.

But if he is still (well) before the closest point of approach at the 1st bearing, he has atleast as much time after the closest point of approach. Because his track is symmetric around that closest point of aproach. Since the unknown range and speed is proportional, but speed likely has some maximum limit (I don't find many merchant beyond 12 knots in Sh3), you can figure out this maximum possible range aswell. If you know how big your sensor range is you can also figure out how far he can move before he leaves that sensor range. Since that closest point of approach was obviously inside sensor range, comming to a parallel course and sail surfaced at overtake speed ('peddle to the metal') would eventually get him back inside the sensorrange. But when that is is tough to say without knowing the actual speed or range, or time of signal loss.

If you have multiple targets all this sonar only targeting goes right out the window with the inability to resolve one target from another, yet another indispensible advantage of modern computers with their database of just about every ship on the ocean, which can pick an individual target out of a crowd and follow it to the exclusion of all the other targets.

Or it can identify essentially all the members of the convoy by name and target all of them simultaneously.

So what do you do when you detect a convoy on sonar? Run away? That would seem the prudent course for a U-Boat late in the war if survival is your aim.

I haven't chased many convoys or multiple units this way. (I seem to run into single units more, or intercept most convoys based upon radio reports with reliable data) I don't rely on the lines of sound on the map, but listen myself to the noises as I move the needle and take the bearings from that notepad. (the 3d hydrophone panel is tilted to the view making it difficult) It would require tracking the convoy as a whole. And this is definately not easy or accurate. But the best I have at the moment. Sometimes you just have to make due.

With a bit of passive sonar/hydophone practise you will be able to pick out the different ship types and follow them. As RR says, todays computers were the sonar operators ears and brain in those days.
You still have to program/teach the computer the different ship signatures, which is the same as spending countless hours on the sonar.

When I spent a lot of time with SH3, I could fire blind at a target, just by the Speed/Rev count and hydrophones. I would just sit there scanning, and pick out the ship I wanted. Once I had the ship, it was a quick peek to see where it was, and that was it.

It was a bit rediculous, but my tonnage sunk per patrol ranged from 28K-89K, with RUB @ 100% plus Real Navigation. Comparing this to the Real Life tonnages.. maybe the game isn't quiet right ?
:D