How do you determine AOB without the length of the boat?

[Able72]

How do you determine AOB without the lenght of the boat to give you a visible aspect ratio percentage?

Here is a copy of a page from the recognition manual I have in game:

[Fincuan]

I always try to determine the target's course by plotting, because when you have the course you don't basically have to care about the AOB. If you for some reason need the AOB, then the TDC will now tell you that. If the situation requires shooting before I have the course I'll just eyeball the AOB and fire.

[Rockin Robbins]

When I have to find AoB I already have the information to measure it directly off the plot. I'm going to assume imperial measurements here, but if you're using metric the time is three minutes fifteen seconds and you're measuring in meters. Conversion works the same way.

Let me explain. The first piece of info I need is the target speed. So the scope goes up and I switch to the nav map. Pop up the stopwatch, mark the ship's location, start the stopwatch and down scope. At 2:40 or so, pop up the scope, lock on the target and switch to the nav map. At 3 minutes, mark the position of the target and down scope.

First, take the ruler tool and connect the marks, extending the line in the direction of the target's movement. This is the track: the course the target is on. If help is on (by opening the compass) you can use the compass rose on the ruler tool to read off the target's true course.

Then you need the speed of the target. With the compass tool click on one mark and drag to the other. You can then read the number of yards the radius of that circle is. The speed in knots is the number of hundred yards (or meters) run during the time. So if the ship sent 750 yards, the speed is 7.5 knots. 1200 yards = 12 kt. You can enter that speed in the TDC right now.

It's time to find that Angle on the Bow. Up periscope and lock on the target. Switch to the nav map and use the protractor tool (shaped like a triangle). Left-click on the track ahead of the target, then on the middle of the target and finally on the middle of your submarine. You'll see the angle measurement beside your target at the apex of the angle. That's your AoB. Now it's starboard or port, depending on whether you are looking at the starboard or port side of the target.

Simple enough? And you got an elementary course in plotting too! I encourage you to use a plot instead of the crew estimate method. You can't check the crew estimate. They can tell you any old thing and the first clue you have is when the torpedo misses.

[Able72]

thank you I really appreciate it.

Care to write a detailed tutorial on plotting? Or can you point me to where I can find one? Real world source or game source I don't care. I could really use it.

Better yet, a video tutorial with step by step detailed instructions

*edit* WOOOHOOO!!!! I just sank my first boat with manual targeting Thank you so very much. That whole plotting blurb you gave just let me sink my first 8500 tons through manual targeting. I think I"m prouder of that little 8500 tons than I am in any of the 500,000+ tons I've sunk before it.

Thanks so much again.

Originally Posted by Able72

How do you determine AOB without the lenght of the boat to give you a visible aspect ratio percentage?

You do that by comparing the standard aspect ratio to the presented aspect ratio.

Standard Aspect Ratio (now SAR) is the ships length divided with the ships height from waterline to masttop.

So with the Mogami its SAR is 656/113,5 = 5,779=5,8

Presented Aspect Ratio (now PAR) is the ships length in periscope tics divided by the height in the periscope in tics.

now to find the AOB you multiply PAR with 100 and then divide with SAR

PAR x 100
--------- = Variation in %
SAR

Now you bring out your Angle on the bow aspect scale rule and find the AOB from the variation - or - you bring out a sinus scale and look the percentage up.

[Able72]

great, so how do you get the standard aspect ratio and how do you mesure the presented aspect ratio? lol, nvm plotting worked and I didn't have to use a calculator. Also, come to think of it, how many enemy boats would we have real precise lenght mesurments for? you think they just gonna hand those over?

[Rockin Robbins]

Originally Posted by Able72

thank you I really appreciate it.

Care to write a detailed tutorial on plotting? Or can you point me to where I can find one? Real world source or game source I don't care. I could really use it.

Better yet, a video tutorial with step by step detailed instructions

*edit* WOOOHOOO!!!! I just sank my first boat with manual targeting Thank you so very much. That whole plotting blurb you gave just let me sink my first 8500 tons through manual targeting. I think I"m prouder of that little 8500 tons than I am in any of the 500,000+ tons I've sunk before it.

Thanks so much again.

Woooooo Hoooooooo! Good job. I'm working on making tutorial movies but have a synch problem between audio and video with Hypercam that I have to get sorted out. I'll be doing seminars on plotting, Dick O'Kane targeting and Fast-90 targeting for the U-Boat.

But right now I have the video racing ahead of the audio and don't quite know why. Once I get it sorted out I'll be in production.

[Rockin Robbins]

Originally Posted by Mav87th

You do that by comparing the standard aspect ratio to the presented aspect ratio.

Standard Aspect Ratio (now SAR) is the ships length divided with the ships height from waterline to masttop.

So with the Mogami its SAR is 656/113,5 = 5,779=5,8

Presented Aspect Ratio (now PAR) is the ships length in periscope tics divided by the height in the periscope in tics.

now to find the AOB you multiply PAR with 100 and then divide with SAR

PAR x 100
--------- = Variation in %
SAR

Now you bring out your Angle on the bow aspect scale rule and find the AOB from the variation - or - you bring out a sinus scale and look the percentage up.

Methinks this guy has done this for real.

[joegrundman]

I also wrote a brief tutorial aimed at helping you to improve your ability to judge aob by eye

http://www.subsim.com/radioroom/showthread.php?t=134200

As for how the length was estimated

the US used a variety of methods as can be found in section 501 of this manual:

http://www.hnsa.org/doc/attack/index.htm#chap05

The Kriegsmarine, however obtained length for the aspect ratio through experience. at the beginning many submarine officers had worked in the merchant fleet and knew a lot about mercahnt shipbuilding, which tended to follow standard procedures around the world.

The number of cranes, for example, indicated the number of cargo bays. A cargo bay tended to be of standard size, and so the number of bays indicated total displacement. Total displacement indicated length and width at beam.

So they used a formula to obtain target length based on observation of these characteristics.- at least this is what Hitman told me

[Rockin Robbins]

Into a stickied thread on attack technique! Probably we should have a thread for Fleet Boats and one for U-Boats, since the methods differ with the change in equipment.

One caution on the aspect ratio method of AoB determination. It is subject to the same error as the stadimeter. Mast heights on enemy ships are not known with certainty and certainly some or most are in error. Also masts are sometimes altered in height to throw stadimeter reading s and aspect ratio AoBs into error. Capn Scurvy has determined that most mast heights in the game stadimeter database are different from the actual ship. This will introduce some error in your calculated AoB. Fortunately, AoB is a very forgiving parameter and I wouldn't expect too many missed shots as a result.

If this results in a combination AoB and range error, however, the effect could be VERY important.

[Able72]

The AOB and range errors caused by these two inacuracies only become significant some time after the initail firing solution is calculated.

In other words, as more time passes, the inacuracy introduced by the stadimeter range and AOB calculations beomes greater. Increasing the likelyhood of a miss. So update your range and AOB information often to keep your solution 'close enough' to on target.

[Able72]

Originally Posted by Rockin Robbins

Into a stickied thread on attack technique! Probably we should have a thread for Fleet Boats and one for U-Boats, since the methods differ with the change in equipment.

One caution on the aspect ratio method of AoB determination. It is subject to the same error as the stadimeter. Mast heights on enemy ships are not known with certainty and certainly some or most are in error. Also masts are sometimes altered in height to throw stadimeter reading s and aspect ratio AoBs into error. Capn Scurvy has determined that most mast heights in the game stadimeter database are different from the actual ship. This will introduce some error in your calculated AoB. Fortunately, AoB is a very forgiving parameter and I wouldn't expect too many missed shots as a result.

If this results in a combination AoB and range error, however, the effect could be VERY important.

Ok, looked at your The Dick O'Kane (UB & FB) and Fast-90 (UB only) attack methods.

I just wanted to confirm, the only pieces of information you need for that attack method is the targets speed and bearing? Wait, I'm confused again damnit. I know its not as hard as I'm making it.

[Quillan]

If you are firing from 90° to the target's course (or very close to it), then range is not really important. If you are firing at some other position then range is important. The manual targeting technique I've been using is based on the Dick O'Kane method, but with a couple of adjustments.

1) I find the target course and speed using the listed methods, and plot the target course on the nav map.

2) Using the course and speed information, I pick an intercept point and maneuver my boat to that position, then stop and wait for the target.

3) I pick a firing position, turn my scope to the chosen bearing, input range to target at the firing position (taken from the nav map), and then adjust the AOB so that the true course indicator on the top wheel of the TDC matches the target course on the nav map.

4) I wait until the target ship crosses the firing point, then fire as each point I wish to target crosses the line in the scope.

I use the map tools to figure out the range to where the target will be at the point I fire. Realistically, I wouldn't have the GPS accuracy on my own position that the game gives me, but I could use the sonar to figure out a range to target up to 5k yards away and then solve for the range at the firing position, so it works anyway.

[Rockin Robbins]

Originally Posted by Able72

The AOB and range errors caused by these two inacuracies only become significant some time after the initail firing solution is calculated.

In other words, as more time passes, the inacuracy introduced by the stadimeter range and AOB calculations beomes greater. Increasing the likelyhood of a miss. So update your range and AOB information often to keep your solution 'close enough' to on target.

I HAVE to start making videos. This stuff fascinates me. OK, the reason Able means that the innacuracies become greater is that you are running your position keeper. And it's a tricky monster.

If the AoB (defines target course) and speed are correct and your range is wrong, the range error will remain constant forever. Thought experiment. Suppose your bearing is a couple of degrees off and the range is 100' too close. We'll say that fixes the target in error 250' in front of the target. If that mistaken location moves with the PK at the same speed and direction as the target, the error will remain constant. Can you see it?

I'll save the rest for when I get my video technique down. But you are correct for other errors: they grow over time with the PK on.

[Rockin Robbins]

Originally Posted by Quillan

If you are firing from 90° to the target's course (or very close to it), then range is not really important. If you are firing at some other position then range is important. The manual targeting technique I've been using is based on the Dick O'Kane method, but with a couple of adjustments.

1) I find the target course and speed using the listed methods, and plot the target course on the nav map.

2) Using the course and speed information, I pick an intercept point and maneuver my boat to that position, then stop and wait for the target.

3) I pick a firing position, turn my scope to the chosen bearing, input range to target at the firing position (taken from the nav map), and then adjust the AOB so that the true course indicator on the top wheel of the TDC matches the target course on the nav map.

4) I wait until the target ship crosses the firing point, then fire as each point I wish to target crosses the line in the scope.

I use the map tools to figure out the range to where the target will be at the point I fire. Realistically, I wouldn't have the GPS accuracy on my own position that the game gives me, but I could use the sonar to figure out a range to target up to 5k yards away and then solve for the range at the firing position, so it works anyway.

You could use radar before he was even in sight. So for both reasons I don't feel bad about keeping map updates on with Trigger Maru.