Angle on the Bow

[hachiman]

Whats the easiest or quickest way to work out AOB ?
I'm not a maths genius and can just do basic arithmetic so please don't talk about sins and cosins and stuff like that !! :p
Is'nt there some sort of wheel i can print off ?

Thanx

[mookiemookie]

Use your PROTRACTOR to draw a line starting at a point along the target's path and extend it to the middle of the target. Click and then draw the second line to the middle of your ship. That angle is your AOB. All you have to know is whether it is port or starboard.

Edit: Thanks Bando

[Bando]

Like mookie, but I'd use protractor

[mookiemookie]

Like mookie, but I'd use protractor

Whoops...that's what I meant. I stand corrected. It's early in the morning and I'm moving. :yep:

[heartc]

Whats the easiest or quickest way to work out AOB ?


You look at it.

[switch.dota]

You look at it.
Good luck guesstimating a 20 or 70 degree AoB.

[heartc]

You look at it. Good luck guesstimating a 20 or 70 degree AoB.
No problem. How is that difficult? Really, you don't even need to think in terms of "Is that 10 or 15 degrees?". With that handy AOB wheel you got that ship symbol in a birds eye view. When you look at the target, you just picture the situation from above and turn the wheel accordingly. Really has more to do with looking at it than calculating anything.

Also, I'm pretty sure most people try to fire from too long a range. iRL a firing range of below 1500 yards was advised, and most skippers fired from at or below 1000 yards. The shorter the range, the less small solution errors will matter.

The only thing you might have to calculate for a firing solution is speed. When you calculate AOB, you are wasting a lot of time for just a bit more accuracy - maybe.
PS.: Playing with map contact updates on and drawing two lines is not calculating AOB. ;)

[John Channing]

PS.: Playing with map contact updates on and drawing two lines is not calculating AOB. ;)

Sure it is... within the confines of the game.

In real life the tracking party would establish a rough estimate of the course of the target based on range and bearing information provided either by the Cap. or XO's periscope observations or from radar data. From there they would use exactly that proceedure to establish the initial AOB. This would be compared to the Captain's estimate and then a big slap-fight would break out about who was right and the target would slip away.

But seriously folks...

The Archerfish had established the AOB of the Shinano from radar tracking long before they ever had it in view, using this process.

JCC

[sqk7744]

Whats the easiest or quickest way to work out AOB ?
I'm not a maths genius and can just do basic arithmetic so please don't talk about sins and cosins and stuff like that !! :p
Is'nt there some sort of wheel i can print off ?

Thanx
Please take a look at this thread:
http://www.subsim.com/radioroom/showpost.php?p=579018&postcount=115
cheers :arrgh!:

[NefariousKoel]

I use the Schwarz. Oh, and guesstimating gets pretty close after a lil practice.:rock:

[heartc]

PS.: Playing with map contact updates on and drawing two lines is not calculating AOB. ;)
Sure it is... within the confines of the game.

Well, the problem with automatic functions in simulations has always been that in the end, a computer will naturally be doing it, no matter how much you wish it were humans. In some cases, the "human crew" is simulated well, in other cases, it is simulated poorly (too good).
An example for a good simulation of the crew is the now properly working chronometer. You take the observations, and based on those, a result will be "worked out" (in fact: computed). When you enter BS information, say, a wrong range, then the result will also be bollocks.
Map contact updates on however is a very poor way of simulating a "plotting party", because the result is instantanous and accurate. It is in fact rather a simulation of a high tech real-time radar, with IFF and target type identification, something the air to air radar in 5th generation fighters like the F-22 might be up to. A better way to simulate the plotting party here would be to take a similar approach as with the speed gathering: You take range and bearing, several times, and based on your observations the ships will be drawn on the map with their projected tracks. Something like the PK does when map contact updates are on, but *without* the actual ship positions magically drawn.

I myself play with map contact updates off, and sometimes on. I can't really decide. ;) The reason why I *do* like to have them on is in fact because of the submerged condition: When closing in submerged or engaged by several destroyers, the simulated sound man is not really up to the task. You'll end up either babysitting him or manning the sonar station yourself. Both of which is unnerving. In real life, the sonar operator could prioritize and tell you about the highest threat at a time, which might *not* be "the nearest warship" etc. And he could turn the wheel very quickly. So, having the bearing lines drawn on the map might be a good compromise. But the contact info when surfaced is a bit too good.

[Rafter11]

You look at it. Good luck guesstimating a 20 or 70 degree AoB.
No problem. How is that difficult? Really, you don't even need to think in terms of "Is that 10 or 15 degrees?". With that handy AOB wheel you got that ship symbol in a birds eye view. When you look at the target, you just picture the situation from above and turn the wheel accordingly. Really has more to do with looking at it than calculating anything.

Also, I'm pretty sure most people try to fire from too long a range. iRL a firing range of below 1500 yards was advised, and most skippers fired from at or below 1000 yards. The shorter the range, the less small solution errors will matter.

The only thing you might have to calculate for a firing solution is speed. When you calculate AOB, you are wasting a lot of time for just a bit more accuracy - maybe.
PS.: Playing with map contact updates on and drawing two lines is not calculating AOB. ;)

I think it is a big problem. AOB is critical to your torpedo solution. If you don't nail speed and AOB, you waste a lot of torps. In my experience, the AOB as viewed through the periscope/TBT is often much higher than reality.

So I think the best way is to plot the target and use the protractor to measure the AOB. That will be damned accurate and unless the target changes course you won't have to do anything but check your moving protractor angle against the TDC angle

Rafter11

[heartc]

I ususally approach my targets on a lead course, having it at around 30-45° (or 330-315°), depending on target speed. When the bearing does not change, I know I'm on the proper intercept course. When closing into firing range, I change course to minimize the gyro angle. At that point, AOB will then usually be in the 45-75° range. The closer the target gets, the more the AOB increases. In any case, I enter what I see. I turn the AOB wheel so that the ship depicted in it has the same facing as the one I see. Then I fire from around 800 yards. I don't remember the last time I missed. It really is not difficult.

Target speed is what can really screw your solution. Range is most unimportant, almost irrelevant for the gyro angle (but becomes important if you use it for speed calculation). AOB is somewhere in the middle, becoming less important the closer the range is (and the lower the AOB is, though this might not be a great advantage because the target will also be "smaller").

Of course, prior to all that I already entered target data in earlier observations and check the validity via the PK relative target bearing output, mostly to gain good target speed. When the bearings match over a prolonged period of time, everything should be fine, so often I only take a last target bearing during the final shooting observation if the bearings drifted from one another only by a small margin before.

[Bando]

I agree with Rafter. I'm playing without contact updates, but plot very frequent. Using the protractor after having plotted, filtered and calculated a lot I'll use the solution and fire with the scope down. I've learned to trust the work I've done beforehand. On normal convoys, ships travelling alone it gives good results. With Taters mod (new campaign layers) it's a bit more tricky. Just like real life, I keep telling myself.......

[heartc]

-edited this into my previous post-

[sqk7744]

Here's a great real life way to do it via visual sighting:
http://www.subsim.com/radioroom/showpost.php?p=493816&postcount=5

* I do enjoy plotting AOB with the protractor more thou

[joegrundman]

Forget that map contact updates nonsense. You are kidding yourself if you think that that is in some way a realistic option. Anyway once you get the hang of dealing with the problem properly you'll be amazed you ever even bothered with map contacts on.

Getting accurate AOB is not so hard, but there are many ways of doing it. Here are some that I use:

Method 1
Small AOBs (up to 20degrees) can be accurately observed visually. If you are looking at the ship head on you see something like this:

I___I___I

The two outer edges represent the port and starboard side, the middle line is the bow.

If the bow is in the middle, the AOB is 0

If it looks like this

I____I__I

Then you have AOB Starboard 10

If this
I_____I_I

You have starboard 15

An accuracy of to the nearest 5 degrees is perfectly enough.

Method 2

For AOBs between 15 and 60, you can use the aspect ratio method outlined by Hitman.

This takes advantage of knowing the ships length, which for some reason was not included in the SH4recog manual, but there are some mods that have restored it.

In this case the aspect ratio is the target ship's length divided by it's height. The observed aspect ratio divided by the known aspect ratio gives the sine of the AOB. This calculation is time consuming at first, but soon becomes easier. You can use a circular slide rule, like one that is on the back side of the Submarine ATtack Course Finder (SACF or ISWAS) to enormously spped up the calculation.

After a short while you get to know the Aspect ratios of many common targets too

Hitman has also produced an as yet unfinished circular whiz wheel that greatly speeds up this technique.

Method 3

Bearing and plot method outlined above. Works well, but is time consuming and has plenty of inaccuracies and requires a large number of peri observations to get a really accurate fix. By the way, building an ISWAS or SACF massively speeds up the process of obtaining AOB from target course and vice versa

Method 4

Constant bearing method. Again using the SACF for the calculation (see my guide in the sig), if you have knowledge of target speed you can calculate AOB and vice versa

Method 5

Matching course and speed will also give you AOB

Method 6

Sonar based target motion analysis can also give AOB

Conclusion

Just as in real life, there were many ways to skin this particluar cat, but they didn't have automatic map updates on.:arrgh!: