AOB Questions - please help me :(
 

Hello

I have been playing SH3 (never on realistic settings) and now SH4 (have gone for it and have TM1.6 and full realism on) off and on for a while now, I've been hanging around these forums reading all the helpfull info from time to time. Well i am addicted to SH4 now, and with all the mods created by everyone you have improved SH4 10 times over, well done to everyone who has done them all.

Anyways to the point, what I am struggling with really really badly is how to calculate the angle on bow, I currently guess it but its giving me a very low hit rate. I have searched the forums for info and keep finding different ways etc, but I was hoping someone on these forums can give me the definate answer "Orion you do it like this, the easy way". I have watched the videos Wernersobe made and they have helped me allot so thank you for them, but I am still struggling on how you calculate the AOB correctly, Ive also seen people use a AOB type protractor mod, could someone point me in the right direction to get hold of it if thats what I need?

Well all help would be appreciated, I really want to get better at this game and feel confident with all the realism switch on.

Thanks in advance

Orion. :)

guy, after 1.3 it's very easy to at last calculate the AOB w/o resorting to "gesstimates". to get the AOB, do this... say visually track, identify and lock ur target. calculate range (with the dial) and send it to TDC. then wait. (with lowered periscope.) later (about the time u think u'll take the shot,) goto periscope, and lock ur target again. calculate range (again). and it u did it well THEN u can ask ur officer to give u a good estimate to the target's speed pressing the "chronometer" button on the speed TDC dial. the officer has not only given u the target's speed, but also its heading. NOW u goto buisness! click the AOB dial and on the opposite side of the screen (see the target position dail as well as the angles of ur torpedo and its hit according to ship?) the upper dial on the left. it shows the ship's heading in relation to the AOB. now turn the right AOB dial untill the target's heading is what the officer said it was in the upper left dail! understand? http://www.subsim.com/radioroom/showthread.php?t=118923 this'll explain it better.

Then there's the WernerSobe method
 

Now I'm going to call this the WernerSobe method because I first saw it clearly explained in his videos, but it existed before that. *ducks*

I don't like the estimate after 2 sightings method because if you measure a range wrong, the AOB ends up wrong. You'll never know it until the torpedo misses. And if the target changes heading, again you won't know it. I believe nothing takes the place of a plot.

The plot starts by calling up the stopwatch and your pencil, marking a starting position for your target and punching the stopwatch button. Time 3 minutes to start and mark the ending position of the boat. Measuring the distance between the two with the compass will let you calculate the speed. For a 3 minute timing, you take the measurement in miles, multiply by ten (just drop the decimal) and double it. A measurement of .3 miles means the target is going six knots. Leave the stopwatch running until six minutes to double check that speed. This time you don't have to double the number, you'll measure .6 miles, meaning 6 knots.

But the plot gives you much more important information too. Connect those plot points and extend the line in the direction of target movement. This is the target's course. Now at a glance, you can tell if the target changes course! With help on you can use the ruler tool to measure the exact course of the target. This is invaluable to plotting an intercept course. And you can immediately tell if the target changes speed or course. This will eliminate many wasted torpedoes.

Now you want the exact AOB? Take your protractor tool and first click on the course line ahead of the target, then click on the target itself. Lastly click on your boat. You can see the angle measured right inside the angle there by the target. That is his AOB. Make sure to enter that starboard or port depending on which side of the target you are looking at. This is the most accurate way to measure AOB for the purpose of achieving torpedo accuracy. (Actually, you are not measuring legal angle on the bow at all but we don't care about that. This will sink the enemy.)

You can use this course information. On the TDC (left side, not the input portion on the right side of the periscope) you can see the AOB measurement ring on the inside. But the outside ring is the course of the target! By adjusting the AOB to achieve a perfect course of the target, you get the absolute most accurate AOB for the TDC that is attainable. Where does that course come from? The plot.

Start the Position Keeper right after you have a speed, range and AOB in the TDC. If the target doesn't change course or speed and your inputs are accurate, you can check the PK against the actual position of the target to see if you have made any errors. You started your plot way before it was time to shoot. When he comes into shooting range you should be so synchronized that you can lower the scope for the last five minutes and shoot with the scope down. The next sound you hear will be BOOOOOOOM!

Once you get comfortable with plotting and hunger for more, there is a program on Subsim called MoBo, the Electronic Maneuvering Board and Dead Reckoning Plotter. It will do all the measuring for you, leaving you just to slide yourself, targets and nodes around on the plotting board. It automatically plots course, speed, angle on the bow and it makes coffee! Actually I made up the part about the coffee. Maybe that will be in the next version.

So use that chart table. It isn't taking up all that space in the control room to give you somewhere to eat.:lol:

And how does that differ from what the crew does automatically? It's also based on measuring two sightings, so if you get the distance wrong the problem persists.

The way I use to make extra sure is having a second opinion. I take the first measurement of the distance, mark it on the map, wait three minutes, do the three-minute rule, then ask the crew. I use an average of both angles / speeds and fire a couple of torps to make really sure.

It only goes the way of the pear when the target changes course (not unlikely in TMaru 1.6 where one out of ten DDs can see at night from miles away) or when torpedoes go dud on me (I hit a kongo with two duds yesterday)

The best way I found to practice your AoB estimates is to leave map contact updates on and look at the attack map (2nd button from left on Nav tab).

When your scope is up and you've just input all the goodies, check that screen and a white line will show where your estimated target should be and the line shows it's estimated heading. Go back and adjust the AoB until you're happy with the results.

After doing this for awhile you'll get a feel for estimating the AoB quite accurately the first time you try and then you won't even need to check the attack map, you'll be so damn good at it. :smug:

That's a good point. I'm used to the Trigger Maru mod where a lot of that unrealistic stuff is removed. There are no ship silhouettes, lines for target heading or torpedo tracks. The attack screen is still usable, but I'd recommend not using TM until you are pretty good without it.

@Doolan As I explained, the utility of the plot is to be able to spot immediately any changes in target course or speed, and to detect errors in the crew's estimate of speed and course. You'll find the plot is always a more accurate tool than using the two sights and ask the crew method. Yes, a spread will compensate for the slop factor, and yes you should use a spread even if you're perfect like I'm not. lol As you implied, success is the result of planning for and mitigating the effect of the inevitable errors that happen in combat.

Interestingly, in real WWII subs the input was usually based on a gut-level eyeball assessment of the AOB. Skippers trained with model ships on turntables, comparing their visual estimates with actual numbers and got quite good at it. Wonder if someone could make a trainer for us? In SH3 there is a mod for the recognition book that lets you rotate the silhouette to reproduce what you see in the scope and tells you the AOB. That would be real cool here!

Great points!

Here's a depiction that may be helpful:

http://www.subsim.com/radioroom/show...&postcount=115

Thanks for the help :), I am getting better, I have hit with a few torps, I am still to sink something with torps only, I keep having to use my deck gun to finish them off. Will keep practicing, thankyou :).

Welcome to SUBSIM :up: ORioN17


RDP

Glad you’re getting the hang of it ORioN17, it really is fun!

The Crew of the Wahoo SS-238, used to place a Ship model on a lazy Susan and turn it at different angles while the XO looked through the opposite site of binoculars to guess the AOB.

Estimating the target's course was generally considered the most difficult of the observation tasks. The accuracy of the result was highly dependent on the experience of the skipper. During combat, the actual course of the target was not usually determined but instead the skippers determined a related quantity called "angle on the bow." Angle on the bow is the angle formed by the target course and the line of sight to the submarine. Some skippers, like the legendary Richard O'Kane, practiced determining the angle on the bow by looking at IJN ship models mounted on a calibrated lazy Susan through an inverted binocular barrel

It really just takes some practice as you focus on the center of the ship's hull, draw a line from that to your sub and then decide if the ship's bow is port or starboard, and then guesstimate at what angles. The great angle views in the IJN Recognition Manual are also very helpful.

For practice, take a look at the Sub School torpedo Attack mission. Using this:
* Note, using the protractor is a longer way of doing AOB, but it may help you visualize the situation.

Load #3 Torpedo Attack:

Here's what you should see after a minute or two into the simulation:

Subs' Heading = 000 due north and speed 0
Target heading = 102.674 (let's use 100)
Bearing to Target = 325
AOB = 45 (42 if using Target heading of 102-103)
Target speed = 9knts

* TIP: once in Map view F3 hit backspace to pause the sim. When ready, hit the NumPab + (plus) key to continue.

You can check this by drawing a line out from your sub's center with the distance tool on your course to the 8^ 13' N

Now draw another line from the target's center until it intersects your course line.

Take the Protractor and draw a line from the Intersection point to the Target's bow, now left-click and draw another line to your bow. The Angle on the Bow should = 45 degrees for AOB=45.


Cheers,
:know:

right this is easy ATB is either port or stb in definition


imagine your self on the ship your looking at looking at your submarine (what side of the ship are you looking from ) =stb

now true bearing 325 (above post ) the reciprocal of this is 145 (easy to calculate plus 2 minus 2 or minus 2 plus 2 to the bearing 325 ) it becomes 145 (minus 2 off the 3=1 plus 2 on the 2 =4 therefore 145


targets true course 100 so what do you do to the recip bearing to get to 100 (you subtract it therefore port =plus starboard = subtract (you had to subtract 100 from 145) so the answer is 45 stb
its that easy plz refere to my ages old post on MANUAL TMA

This is what I do. I start off the way rockin explains it. then once the ship gets closer i'll get the input from the crew. if there is no escorts around i'll even get a ping from the sonar :D. I'll compair what i have to what the crew says. If i feel the crew has a better solution i'll use that one, usually there right on. Now if i've bungled the approch or the merchies are not blindly walking into my setup and i dont have time to get into a better approch (usually i've been spotted and a escort is charging down at me) I'll give crawlers way a go just to get a shot off usually at the escort. It is the quick and dirty meathod doesn't always work but hay somtimes the merchies just dont want to cooperate and take a torpedo amidships:down: .


One other thing to help you out guessing the AOB. At 45º the ship is roughly half its length. so that means the 300ft ship looks about 150ft with an AOB of 45º. Of course that being said the closer the ship gets to 0º, or 180º the smaller the ship will look. and the closer a ship gets to 90º the bigger it'll look.

Hope that help.

I have a favorite method I use for quick solutions or when its too dark to identify targets (or if I just can't find him in the ID book). This method doesn't care what the target is and doesn't require any identification of the target, it only uses information your crew provides via the chart. (I never play with "no chart updates" on or "no external camera" since the guy standing by the chart table should be doing something, and I like screenshots)

Once a contact is made (and you are ahead of target and preferably at periscope depth) zoom into your chart (regular, not attack). Find your target ship and draw a line through it from stern to bow (if using Trigger Maru mod like I do they will be just blobs and not directional icons). Draw the line way out till its past your location. Adjust the line using 8 TC (time compression) to get it so the ship is traveling straight down the line.

I then mark a 1 nm start and finish and time the ship over that distance then use the chart helps on the TM map to determine its speed based on time taken and send to this to the tdc. If its daylight I will sometimes guesstimate the speed based on ship type and bow wake. (An error of 1-2 knots +/- will not matter if your firing at or below 1000 yds.)

Lower periscope. If time allows, maneuver your sub into firing distance 500-1000 yds off the enemies bearing line.

Once in possition, stop your boat. Draw a line out from your bow or stern (which ever you will fire from) where it crosses the enemy bearing line will be your "intercept point". Determine the enemies AoB at the intercept point using the enemy bearing line you drew and your subs planned bearing when enemy reaches the intercept point. Eyeball the sub icon and the enemy ship icon in the tdc till they are facing close to how they will be when the enemy reaches the intercept point. You might find it easier to draw a bearing line through your sub until it intersects the enemies bearing line. The easiest way is to just make sure you are 90 degree to him at intercept point so he is "crossing the T".

Send the AoB to the tdc. (This is the least critical of the data you send if your firing at or under 1000 yds so just get it close as possible.)

Now manually set your distance using the interior numbers on the mast height wheel. Keep in mind that you don't care about his current distance, just the distance where he will be at the intercept point, where you plan to fire. You can get this distance by using your compass tool to draw a circle around your sub or using the handy template surrounding your sub in the Trigger Maru mod. Where the circle or template square intersects the intercept point is the distance when you will fire (optimally 500-1000 yards). Keep in mind you DO NOT have to be bow/stern on to this spot since the gyroscopes will be set later when you send bearing to tdc, but your AoB is easier to calculate if you are. Don't bother sending the distance to the tdc yet since you still need more info.

You should not have turned on the PK (possition keeper) yet.
You now have a solution that is spot on for a hypothetical enemy located at your intercept point.

Using quick periscope peeks or distance over time based on speed calculations wait till your enemy reaches your intercept point, raise your periscope and possition the vertical cross hair near where you want the lead torpedo to hit. I usually just hit "L" and lock the view to amidship. I use the LBO (Living Breathing Ocean mod) and have "stabilized periscope" turned off so it is sometimes hard to keep on target manually and select a sweet spot. I also use spreads with every attack which reduces the need to try and hit a specific sweet spot.

Click the "send distance/bearing to tdc" button and turn on the PK. This will also send your previously entered distance. The PK will allow you to quickly update the solution later in case you miss due to an error in your speed calculation. You can drop your periscope at this time too if you like to keep your enemy from changing course if he spots you or to avoid detection by escorts.

While waiting for the enemy to get to your intersect point you should have had time to set your torpedos up and open your tube doors. Select each torpedo you will use one at a time and hit "Q" to open the associated door. Set its speed to the fastest setting and its depth to whatever you like. Don't bother setting spread at this time since it will not save. Use "W" to jump to next tube and repeat.

Once you are ready to fire begin firing your torpedos. I will usually fire tube one using the red plunger at 0 spread then use "W" to jump to tube two and set its spread to -2 degree and hit ctl-enter to fire (TM mod default). I repeat the process for the remainder of my planned fish usually starting with +1 for torpedo 3 and then +2 degree for 4 if I use it. For a 5 fish spread at under 1000 yds I would use
-3,-1.5,0,+1.5,+3.

Using this method I very seldomly miss with any torpedos. Only a grave error in speed calculation would result in a total miss. Thats why I always try to keep at least one torpedo in the tube if I am not confident in my speed guess. That last fish and an updated speed quickly sent to the PKed tdc can slow the target down or disable him till I can get my stern tubes to bear or load some more eels.