What is your TDC up to? the Law of Cos, the perfect torpedo shot

[starvingartist507]

You can download any of my guides from www.hoofinasia.net (http://www.hoofinasia.net)
Also @ hoofinasia, the working stopwatch program I detailed below

EDIT: added the link to the Math guide
EDIT: added guide to main page. Sorry the pictures suck so bad. I'm trying to get my file host back online, but for now, thats the best I can do.

Once you figure out whats going on, I promise that it only takes a minute to figure out this stuff using game data, so its not like you have to pause it for an hour (or at all) to get an accurate speed reading.

To nail down a ship, do 3 things:
1. Figure range
2. Figure speed
3. Figure AOB

When you look at a target, you note several critical pieces of information. The first, Bearing, the second Range. The third piece required for a good shot is Angle on Bow. At first, just estimate AOB, so that you can point your boat in the right direction. Once you are basically in position, knowledge of a perfect heading becomes more pressing. There are a couple ways to figure out AOB and Heading with a totally normal degree of accuracy detailed elsewhere in the forum. This small and poorly illustrated example makes no attempt to dethrone the current guides, but I am trying to provide a way to get exact measurements, which are especially helpful for long range, high speed, or submerged-only shots. This method can even be used to figure a “total forward movement” and “generic heading” for a zig-zagging target, given enough patience and observation time. I might not get into that just now, however.

Let’s start with your average situation. You managed to point your ship somewhere ahead of a hapless merchie, and are bearing down on their estimated course. For the sake of simplicity, we’ll say that you are submerged, and have a good visual contact under 2.5 NM (approx 5000 yds).

Now the method I use can be used to figure exact heading and speed information on the target, even while the sub is moving, but the math gets a lot more complicated. So until I become more adept at spatial reasoning, I usually bring my sub down to a negligible speed, preferably a dead stop. This happens 90% of the time when I am approaching a firing position anyway, since I don’t want the periscope to get noticed, I am moving silently to evade escorts, or I have a little time to kill before the target is in the kill zone. Basically, it is good sub-commanding to bring the ship into a firing position, and let the target drift its way into your sights, no matter what your solution calculating tactics.

So you have a target off to your port side. We’ll imagine that the relative bearing is 330, or 60 degrees left. The target is heading towards you, so the AOB is less than 90 and they are showing their starboard side. If you can accurately identify the target, do so asap. Once this is done, you have to do a few things at once (or as quickly as possible.) First, start the stopwatch, as soon as you do that, figure range. If it is easier for you to get range then click start, go ahead. Remember in all those sub movies you watched as a kid, when the Skipper would yell “Mark! Bearing such and such, range so and so!” Well that is what you are doing. Get a range, get a bearing, and start the timer. Now is a convenient time to “down scope” if you need to be stealthy. Keep that timer going, let some time pass, the more the merrier. I usually go for 2 mins or so a lot more if they are still very far away. Once you are happy with the amount of time that has passed, up-scope, and yell “Mark! Range such and such, bearing so and so!” Don’t piss off your neighbors. Jot down the second range, the second bearing, and the time that has passed. Pause if you want to now, since you are doing the work of 2 crew members and a machine. There’s no shame in working more slowly, but the information doesn’t necessarily get outdated unless your target veers off course or changes speed. So it could be ok to remain going at real time.

Ok, with the two bearing and range readings, you have all the information you need to figure range and speed, and with that, you can not only calc AOB to the degree, you can also predict the AOB on a certain bearing. I.E. when the target is at bearing 350 (or time to shoot) the AOB will be…

So the law of Cosine.
You knew there would be math. The law of cosine states that if you know the length of two sides a triangle, and the measure of one of the angles, you can solve for all lengths and angles. Find the difference of the two bearings. Using the above example, Bearing one was 330, and we’ll say bearing two was 345. The difference is 15 degrees. We’ll say for argument that Range 1 was 2200, and range 2 was 2000. Yarr!ds… or

a=2200
b=2000
c=distance traveled
C=bearing change
B=Angle on bow start
A= 180 - Angle on bow finish.

According to the trig law: The distance of the third leg (which is the distance that the ship traveled) is:
http://www.mediafire.com/imgbnc.php/7dce7a1f33f2224da93a221b62d2128d6g.jpg

Distance Travled^2= First Distance^2 + Second Distance2^2 – 2*Distance1*Distance2*Cos(angle change)

Using our data:
1. add squares of both distances (8,840,000)
Distance 1 was 2200, squared to 4,840,000
Distance 2 was 2000 squared to 4,000,000
2. Figure the Cosine of the angle. (.9659 )
(Remember the difference of the two angles was 15 Degrees. The cosine of 15 is .9659)
3. Double this, multiply by both distances. (8500140)
(2 times .9659 times 2000 times 2200)
4. Subtract the first total (step 1) from the second total (step 3) 339,860
(8,840,000-8,500,140)
5. The square root of this, (582.9751) is the distance that our merchie traveled between the two marked times.
If I waited 2 minutes (120 seconds), this gives me a base speed of 4.852812 yards per second (582.9751 divided by time). From there,
6. multiply by 1.777 to get a base speed of 8.63288 knots.
Any yards/second times 1.777 = knots.

That’s what your stopwatch button is supposed to calculate, but it doesn’t. An exact speed is usually enough to make a perfect shot, with a roughly accurate AOB.

To figure an exact AOB using 2 ranges and 2 bearings:
You know the angle of one leg, 15 degrees, and the opposite distance (582.9751 from the above work, step 5)
You also know the distance of all sides of the triangle. Dusting off your trigonometry book again. Recall that:
http://www.mediafire.com/imgbnc.php/69766287ddfcfa9349d9e13a0e1ed2e16g.jpg
So! Sin of bearing change, divided by distance travled, equals Sine of Angle on Bow, divided by the range at Mark 2. Or!
Find the sin of the bearing change. Recall from above that the bearing change was 15 deg. (0.2588)
Multiply by the second distance to target (which was 2000) (517.6380902)
Divide by the distance traveled (found using the above method) (.889792)
The angle on bow is the inverse sin of this number (so the angle on bow was 62.6136)The greatest part about knowing the exact angle on bow at an exact bearing is that, all future AOB will be related to that. So when our mystery ship was on bearing 330, and had an AOB 62.61; I am absolutely positive that at Bearing 345, it will have an AOB of 77.61. Why? Because all these angles and ranges just graph out a big triangle and all the angles of a triangle have to add up to 180. So trust me:

If the target moves 5 degrees, and you don’t move at all, the angle on bow increases by that amount. Simple as that.

Don’t try to solve for the final AOB, since you are actually solving the “inside” angle of the triangle (see below)…
So if you pop up the scope and figure an AOB of 44 Deg at bearing 50, you can be darn sure that when that target is at bearing 10, that it will have an AOB of 84 Deg. In this way, if you get a sure range and speed, you can calculate and predict AOB with a fantastic amount of certainty. So now you can fix the AOB for any time, and find the target speed with pinpoint accuracy. Those fish should be hitting right on every time.

This can also be used to predict range at a future bearing. Just re-solve with new information, invent any old situation you want. But for the most part, the only thing you need to get a good shot is AOB, Speed, Range. And Range is easy enough to equate, and this will give you the rest, down to pinpoint accuracy.

Remember this method is reliant on accurate range findings, as the manual states. So use the sonar station to back up your calculations. If you use the Sonar to re-check your range, remember as of 1.2 sonar was still bugged, so go the station directly, don’t trust what the sonarman told you, because he’ll just say whatever you have entered on the TDC. Sit down, and ping the target yourself for best results.

To figure an exact heading, knowing their AOB and bearing
This is very easily estimated using the charts, but if you for some reason need to know. As I sometimes do, here’s how I figure it out. Its quick and dirty math.
I just remember, Port = negative, starboard = positive (with straight ahead being the origin), and the enemy ship is opposite.

Take the first AOB that you just calculated, and the first bearing that you noted at Mark 1.
1. Your heading minus their relative bearing if they are on the port side (left), or plus their relative bearing if they are on the starboard (right)
If from the above example, they were at bearing 330, this means 30 port. So take our heading (270) and subtract 30. 240 is the Absolute Bearing
2. 180 + absolute = (heading if AOB=0). So if AOB is 30 starboard, subtract 30 from this result. If 40 port, add 40.

From above, AOB was 62.61 at bearing 330. 330 = 30 to port side. So our heading (270) minus relative bearing since we are looking to port (30) = 240 Absolute bearing, or about WSW. Then take this absolute bearing and add 180, then add or subtract their AOB. So Absolute bearing of 240, plus 180 (420) minus their AOB (which was starboard 62.61) for an exact heading of 357.39. I apologize that the chart below doesn’t perfectly match the math. I was just throwing lines together to show how they relate. But you get the idea I hope!

Happy Hunting! If you actually use this with any measure of success let me know! It seems way to complicated once I write it down…

http://www.mediafire.com/imgbnc.php/e1741700e80cea0c509e1040bfc9f8d16g.jpg

[MONOLITH]

Would anyone be interested in reading how to solve AOB, Target speed, heading, etc with two seperate range and bearing checks?

Yes, I would.

[XanderF]

Would anyone be interested in reading how to solve AOB, Target speed, heading, etc with two seperate range and bearing checks?

Yes, I would.

This thread for you, then (http://www.subsim.com/radioroom/showthread.php?t=112765). More authentic to use a slide rule, too. :yep:

But that's what it gets you. Two separate range and bearing checks, doesn't even really matter how long apart (long enough for there to be some meaningful change in target position, anyway), and you have everything you need to shoot.

[starvingartist507]

anyway...
The point was, I'm not using a slide rule. I dont own one. Like I said, I admire the use of outside tools, I just don't have them. Authenticity is great, I was just thinking about the math involved. Just used pen, paper, and my scientific calc. I'm not too worried about the authenticity of it.

Thanks for the link. I'll see if I can't track down something like whats mentioned. However, I got this typed up if anyone wants to read what I did and I figure I'll just link it in case.

It'll get you exact numbers, and no reading of charts or anything extra to print, just write it down...

You can find my method @ www.hoofinasia.net/TDC.htm (http://www.hoofinasia.net/TDC.htm)

[Swooth]

Even though I'm not good in math, I'll give it a whirl and see if I can understand it. Nevertheless, thanks for the info, greatly appreciated :up:

[MONOLITH]

I just put a hand over one eye to reduce my depth perception and hit the fire key.

Works every time.


:rotfl:

[nattydread]

I only use them to determine distance from track. I determine AoB and speed by eye-balling it.

[Xelif]

Ahhh, you are my hero! I needed an explanation like this, finally a use for that trig I learned those years ago... Now, I haven't tested it myself, but I jotted down some notes and I would like to say your explanation so far is clear and seems perfectly workable! I've been using a different manual targeting method and this is a lot more flexible. I'll respond more after I've had time to wring it out in the ocean :D

(edit) This alone should be in bold in every sub sim manual:
If the target moves 5 degrees, and you don’t move at all, the angle on bow increases by that amount (or decreases if the target is moving away.) Simple as that.

Wow that'll make quickly changing my solutions easy!

(double ed) Your method for calculating AOB could use a little clearing up. Let me work through some of it tomorrow and I'll post again if I am still confused. Need to sleep...

[starvingartist507]

Its important to note my method only calculates the AOB for the first mark, as in the first time you grabbed range and bearing. Then add the number of degrees that the target has "tracked"

1. Sine of ( bearing change ) times Range at mark 2
2. This divided by distance merchant traveled
3. inverse sin of the result = AOB at first observation
4. if the merchie has moved 25 degrees since then, add 25 degrees to AOB
presto!

I noticed I had this wrong in the doc. Corrected it!
Hope this was a little more clear.
also added how to find exact heading, if you wanted to know... but not many people should need that.

[Xelif]

Grrrr I wrote an entire post, then reloaded the page by accident.

Ah, let me seek some clarification on your algebra for AOB calculations.

Initially, is this accurate?

1) c / sin C = a / sin A
Cross multiply out:
2) sin C * a = sin A * c
Isolate and solve for angle A (using inverse sin)
3) sin A = (sin C * a / c)

Now I have to dig my scientific calculator out!! :D

Assuming the above is right, can't you solve for final AoB by using the B portion of the formula?

c / sin C = b / sin B, etc etc solve for angle B?

[Xelif]

Your chart is remarkably similar to what I've got down in my notebook. I just sat down and tested everything. First I ran through your example numbers and got the same result as you (good!). I'm documenting everthing here in the hopes that another reader finds it useful... Starvingartist, you already -know- all this stuff but feel free to critique.

I realized I must be the only person who can't figure out how to switch SH4 from metric to imperial measurement... although I'm entirely used comfortable with metric (SI technically), despite being born in the United States.

Anyway, a quick lookup of meters/second to knots yields a conversion factor of 1.94384. That really helps in setting speed for your torps, using my math :D

Then I loaded up Ol' Faithful - the third sub school exercise, where you start with a not-quite perpendicular cruiser in the exact same place every time. I've trained with this scenario so much I know what the ranges, speed, and angles are, along with the proper torpedo settings. I use manual targeting but have map contacts on, so I can resort to the map for a quick range check / AoB check. This allows me to verify my solutions.

My previous method of calculating speed involved an observation period of 3 minutes 15 seconds, so I was very drawn to this method as it allows any two bearing/range checks to suffice - the further apart the better as it allows finer resolution. I immediately got range/bearing information, waited 1 minute 40 seconds (which works out to 100 seconds, making the math later a little easy... not neccessary but helpful) and took my second range/bearing information.

Relevent data (pretend it's in a sketched out table):
Range, Bearing, Time
1500 meters, 322 deg, 0 seconds
1200 meters, 337 deg, 100 seconds

Also sketched out is what I am going to call the triangle of torpedo love... see the above posts for starvingartists's images of the ABC triangle... I'm sure there's a technical name, so pardon me. Each side has the relevant data filled in, and the direction of travel is indicated just to make sure I don't forget. It helps to remember that the sub is at angle C, and if you view the triangle from that perspective (flip it upside down mentally or on paper), it becomes very clear which measurements are which.

I won't illustrate my math here, mostly because I can't represent exponents properly, but I ended up with the target's net distance travelled of 461 meters, at a net speed of 4.6 meters per second, or 8.964 knots, basically 9 knots... the speed I'd been using all along in this scenario. Yay! Angle on bow was calculating using the above formulas and resulted in 42 degrees, updated to 57 degrees at the time of second observation. This was exactly accurate according to the map (well, depending on where the line is drawn to your ship - it was perfect for my forward torpedo tubes.)

Torpedo solution was similar to every other solution I have used in that scenario... 3 torpedoes fired, 1 premature detonation, 2 hits, slightly aft of where I had been aiming. I did not enable the position keeper quickly enough, so the range solution was slightly too long, resulting in my torps hitting slightly aft - at least, that's what I believe happened. Overall, I was impressed with the accuracy. It took me a lot longer to calculate this by hand than is acceptable in a submarine environment, but the game has a pause key for a reason! I imagine I will get a lot faster with practice. Right now every step was written out so I could verify I didn't make any stupid math mistakes - a classic problem when I was in college :)

I'm going to start using this out on patrols now :know:

[starvingartist507]

I think that when you click "fire" the target settings are fixed. I noticed a VERY substantial delay when ordering a second tube to fire. To compensate, I usually fire all torpedos just a bit ahead of predicted course, since there is no way to *AHEM* open all tubes at once, which would aleviate the problem of constant trailing shots for the second, third, etc tube.

...I think.

Glad it worked out for you. Once you get the steps laid out, it really is just a 1,2,3,4 type of operation, and its faster than plotting and estimating eventually. With a chronometer fix this will all just be academic, but its been a fun exercise, and finding an exact AOB is always useful, since the game never makes that real easy.

Oh well, I'll leave the guide up in the off chance that someone else likes it.

[Xelif]

This is unrelated to your solution calculating, but while we're on the topic of manual targeting... I've noticed very odd things with the manual targeting. For instance, I can't get a torpedo to aim where the optics are pointing, after I've entered in a solution. I have to aim at a new point, then click the range update button. At that point, the new heading is reflected in the torpedo panel to the left. It doesn't update as the periscope turns. I think I can get it to aim optically, but I can't remember offhand how.

Also, it doesn't do any kind of internal updating unless you activate the position keeper (the button on lower right that turns red).

In any case, I have best results by entering a valid firing solution, immediately activating the position keeper button, and firing using the following procedure:
1) Select tube 1
2) Open tube 1 with 'q', wait a few seconds
3) Fire tube 1
4) Select tube 2
5) Open tube 2 and wait a few seconds
6) Modify salvo angle setting on torpedo panel to 1 or 2 degrees right
7) Fire tube 2
8-9) Repeat 5-7 with tube 3, but 1 or 2 degrees left.

It fires a decent spread, and the solution is automatically updated as the target moves, with the position keeper active. The key is opening the torpedo tube, then WAITING five or more seconds (I can't remember offhand if there's a sound... there was in SHIII), then firing. It'll have a more accurate solution.

This is all in my experience of course, and I'm by no means a veteran. I recently got SHIV and have been practicing torpedo attacks almost endlessly, in order to get a feel for the system. If anyone disagrees, please respond :) I'm just trying to figure things out and listing my reasoning so anyone can point out where I'm wrong.

It all started with my torps hitting on the same area of the ship, despite my optics attempting to lead/lag the target. That made me question what the manual said about optical targeting. I finally hit upon the manual somewhat clumsy salvo procedure above. There's time lag between the torps, but as long as the solution is valid and the position keeper enabled, they will be accurate with regards to spread and each other. It's -almost- as good as firing a 3-torp salvo in SHIII, just on a longer timescale.

[MudMarine]

Can this method/math be used with a slide rule? If so how. Just learning to use one,a circular one at that.

[starvingartist507]

well, yeah, thats what a slide rule is for, but theres a thread about that somewhere else. I believe it is here:

http://www.subsim.com/radioroom/showthread.php?t=112765

I don't have one, and don't plan on getting one just yet :)
I'm more interested in applying that Trig I learned, exploring the math behind a good solution. Besides, I already labeled my old casio "TDC".

Also, its nice to use trig to set up a solution even when the sub is moving. No more coming to a dead stop for solutions. I'm not sure if a slide rule can do that, and if it can, thats dope. I just like my good old calc.

[Puster Bill]

Your chart is remarkably similar to what I've got down in my notebook. I just sat down and tested everything. First I ran through your example numbers and got the same result as you (good!). I'm documenting everthing here in the hopes that another reader finds it useful... Starvingartist, you already -know- all this stuff but feel free to critique.

I realized I must be the only person who can't figure out how to switch SH4 from metric to imperial measurement... although I'm entirely used comfortable with metric (SI technically), despite being born in the United States.

Anyway, a quick lookup of meters/second to knots yields a conversion factor of 1.94384. That really helps in setting speed for your torps, using my math :D

Then I loaded up Ol' Faithful - the third sub school exercise, where you start with a not-quite perpendicular cruiser in the exact same place every time. I've trained with this scenario so much I know what the ranges, speed, and angles are, along with the proper torpedo settings. I use manual targeting but have map contacts on, so I can resort to the map for a quick range check / AoB check. This allows me to verify my solutions.

My previous method of calculating speed involved an observation period of 3 minutes 15 seconds, so I was very drawn to this method as it allows any two bearing/range checks to suffice - the further apart the better as it allows finer resolution. I immediately got range/bearing information, waited 1 minute 40 seconds (which works out to 100 seconds, making the math later a little easy... not neccessary but helpful) and took my second range/bearing information.

Relevent data (pretend it's in a sketched out table):
Range, Bearing, Time
1500 meters, 322 deg, 0 seconds
1200 meters, 337 deg, 100 seconds

Also sketched out is what I am going to call the triangle of torpedo love... see the above posts for starvingartists's images of the ABC triangle... I'm sure there's a technical name, so pardon me. Each side has the relevant data filled in, and the direction of travel is indicated just to make sure I don't forget. It helps to remember that the sub is at angle C, and if you view the triangle from that perspective (flip it upside down mentally or on paper), it becomes very clear which measurements are which.

I won't illustrate my math here, mostly because I can't represent exponents properly, but I ended up with the target's net distance travelled of 461 meters, at a net speed of 4.6 meters per second, or 8.964 knots, basically 9 knots... the speed I'd been using all along in this scenario. Yay! Angle on bow was calculating using the above formulas and resulted in 42 degrees, updated to 57 degrees at the time of second observation. This was exactly accurate according to the map (well, depending on where the line is drawn to your ship - it was perfect for my forward torpedo tubes.)

Torpedo solution was similar to every other solution I have used in that scenario... 3 torpedoes fired, 1 premature detonation, 2 hits, slightly aft of where I had been aiming. I did not enable the position keeper quickly enough, so the range solution was slightly too long, resulting in my torps hitting slightly aft - at least, that's what I believe happened. Overall, I was impressed with the accuracy. It took me a lot longer to calculate this by hand than is acceptable in a submarine environment, but the game has a pause key for a reason! I imagine I will get a lot faster with practice. Right now every step was written out so I could verify I didn't make any stupid math mistakes - a classic problem when I was in college :)

I'm going to start using this out on patrols now :know:

You can simplify this procedure immensely, and make it easy enough that you can do it on the fly, if you use a slide rule.

Check out these threads:

Slide Rule Targeting for SHIII + SHIV:
http://www.subsim.com/radioroom/showthread.php?t=112765

If you can't find a slide rule to use, you can make one using the templates here:
http://www.sphere.bc.ca/test/build.html

Any slide rule, circular or linear, will work as long as it has an 'S' (Sine) scale.

If you want historical accuracy, though, you need to build one of these:
Submarine Attack Course Finder:
http://www.subsim.com/radioroom/showthread.php?t=112765 (http://www.subsim.com/radioroom/showthread.php?t=112765&highlight=slide+rule)
(make sure you also get Hitman's reverse side to it: That is the actual 'slide rule' part that you use to calculate target speed with)

[starvingartist507]

You can simplify this procedure immensely, and make it easy enough that you can do it on the fly, if you use a slide rule.

Check out these threads:

Slide Rule Targeting for SHIII + SHIV:
http://www.subsim.com/radioroom/showthread.php?t=112765

If you can't find a slide rule to use, you can make one using the templates here:
http://www.sphere.bc.ca/test/build.html

Any slide rule, circular or linear, will work as long as it has an 'S' (Sine) scale.

If you want historical accuracy, though, you need to build one of these:
Submarine Attack Course Finder:
http://www.subsim.com/radioroom/showthread.php?t=112765 (http://www.subsim.com/radioroom/showthread.php?t=112765&highlight=slide+rule)
(make sure you also get Hitman's reverse side to it: That is the actual 'slide rule' part that you use to calculate target speed with)
anyway...
The point was, I'm not using a slide rule. I dont own one. Like I said, I admire the use of outside tools, I just don't have them. Authenticity is great, I was just thinking about the math involved. Just used pen, paper, and my scientific calc. I'm not too worried about the authenticity of it.

Thanks for the link. I'll see if I can't track down something like whats mentioned. However, I got this typed up if anyone wants to read what I did and I figure I'll just link it in case.


I even linked to the slide rule targeting earlier....

I have already read the slide rule targeting guide

This has little to do with that, since I'm talking about the math behind BOTH the slide rule targeting guide and any other SIN or COS based speed calc...

Please stop linking to that thread, did I mention I've read it? It is a guide to using a slide rule, which I don't have, to figure out the math that I already understand, and am exploring above.

[dean_acheson]

I just put a hand over one eye to reduce my depth perception and hit the fire key.

Works every time.


:rotfl:

:rotfl: :rotfl: :rotfl: I aways seem to put the hand over my good eye though!

[DirtyHarry3033]

I think that when you click "fire" the target settings are fixed. I noticed a VERY substantial delay when ordering a second tube to fire. To compensate, I usually fire all torpedos just a bit ahead of predicted course, since there is no way to *AHEM* open all tubes at once, which would aleviate the problem of constant trailing shots for the second, third, etc tube.
You can have all tubes open at once, you just need to edit your commands.cfg file a little. See this thread for info:

http://www.subsim.com/radioroom/showthread.php?t=111616

Believe me it works great!

DH

[starvingartist507]

very handy! thanks I'll try this out right away!

[Weaverjd]

Looking for the guide can someone pm it to me?

[Puster Bill]

Please stop linking to that thread, did I mention I've read it? It is a guide to using a slide rule, which I don't have, to figure out the math that I already understand, and am exploring above.
Sorry. I'll stop linking to this thread:
http://www.subsim.com/radioroom/showthread.php?t=112765

I promise that I will no longer link to http://www.subsim.com/radioroom/showthread.php?t=112765 anymore in this particular thread. Never let it be said that when someone asks Puster Bill to stop linking to http://www.subsim.com/radioroom/showthread.php?t=112765 that he won't stop linking to it. I'm the kind of guy who when I say I'll stop linking to http://www.subsim.com/radioroom/showthread.php?t=112765 , I actually do stop linking to http://www.subsim.com/radioroom/showthread.php?t=112765.

/Cue old Bugs Bunny 'Shut up shutting up' gangster routine. :D

[Hitman]

Oh you did it again! You linked to this thread http://www.subsim.com/radioroom/showthread.php?t=112765. Didn't he tell you to stop linking to this thread?: http://www.subsim.com/radioroom/showthread.php?t=112765 So why didn't you stop linking to this thread?: http://www.subsim.com/radioroom/showthread.php?t=112765

Listen to that man, he has opened a topic about maths, he doesn't need to read this thread: http://www.subsim.com/radioroom/showthread.php?t=112765, he is just interested in the maths behind the whole thing, so please stop linking to this thread: http://www.subsim.com/radioroom/showthread.php?t=112765

BTW starvingartist507, I saw you had already linked to this thread: http://www.subsim.com/radioroom/showthread.php?t=112765, so I am now sure you know it does not belong here, and that you don't need this link anymore: http://www.subsim.com/radioroom/showthread.php?t=112765

Take it easy :|\\ we're just joking, and if you want to calm down, instead of holding your breath and counting up to ten, try and read this thread: http://www.subsim.com/radioroom/showthread.php?t=112765, works very well:up:

[Argus00]

Oh you did it again! You linked to this thread http://www.subsim.com/radioroom/showthread.php?t=112765. Didn't he tell you to stop linking to this thread?: http://www.subsim.com/radioroom/showthread.php?t=112765 So why didn't you stop linking to this thread?: http://www.subsim.com/radioroom/showthread.php?t=112765

Listen to that man, he has opened a topic about maths, he doesn't need to read this thread: http://www.subsim.com/radioroom/showthread.php?t=112765, he is just interested in the maths behind the whole thing, so please stop linking to this thread: http://www.subsim.com/radioroom/showthread.php?t=112765

BTW starvingartist507, I saw you had already linked to this thread: http://www.subsim.com/radioroom/showthread.php?t=112765, so I am now sure you know it does not belong here, and that you don't need this link anymore: http://www.subsim.com/radioroom/showthread.php?t=112765

Take it easy :|\\ we're just joking, and if you want to calm down, instead of holding your breath and counting up to ten, try and read this thread: http://www.subsim.com/radioroom/showthread.php?t=112765, works very well:up:

Aw, c'mon, quit linking to this thread: http://www.subsim.com/radioroom/showthread.php?t=112765 :nope:

You should link to this one, instead: http://www.subsim.com/radioroom/showthread.php?t=112765 :rock:

:rotfl: :rotfl: :rotfl:

[Puster Bill]

I seem to have created a monster by not linking to the thread-that-shall-no-longer-be-linked-to. :rotfl::rotfl:

/Keeping my promise.

[Wilcke]

LOL!:up: Drinks on you right!

Wilcke

[Xelif]

Wow, excellent job of completely derailing the thread... :doh:

Anyway, doing the calcs by hand a few times shows you the importance of observation time. It also shows where error really matters. The rougher your range calc, the longer an observation time you need. I knew this before, but you get an idea of the percentages involved when you do the math. I'm a lot more patient now, waiting for enough time to elapse for my solution to be accurate! I'm just glad our subs have sonar :D Exact range is handy!

How realistic is the response to a sonar ping for range? I know that with today's equipment, a single sonar ping also lights you up to any decent sonar system in the water. Do the destroyers in SH4 respond to a sonar ping you emit?

[starvingartist507]

How realistic is the response to a sonar ping for range? .... Do the destroyers in SH4 respond to a sonar ping you emit?

I am pretty sure they would, but I havent tried it yet. I know the manual says they respond to active sonar, but that really doesnt mean anything from what I've seen of the game.

also:
I figured out how to use the listed methods to calculate a solution when the sub is moving. Its a little more complicated, and involves solving two triangles, from there, I tried a vector-based approach, calculating the subs "trajectory" and the targets, and was able to calculate accurate speeds. I'm not breaking any ground here. I've had to re-learn all my old math. Now, I'm using my admittedly limited programming experience to make an .exe that will do the job of the in-game stopwatch. So far, it'd have to be run outside of SH4, but I suppose if you have dual-monitor, or run windowed (which might be broken, I heard), it would be pretty handy. I have little to no experience in modding, so I don't know if it'd be possible to "fix" the stopwatch using what I found. If anyone reads this that wants to help (unlikely! ;)) let me know...

btw, I have to pay my respects to the timeless veterans of the subsim forums, lest I feel the fury of their links. so here's a link I copied off the the image that was burned into my retinas by hitman and puster bill:

http://www.subsim.com/radioroom/showthread.php?t=112765

Its a thread, written by puster bill that describes a method of using a slide rule to calculate target speed, assuming the sub is stationary or at "creeping speed", if you didnt know. It documents historicaly accurate tools and methods, as well as touching on the math involved. A good read for nights by the fire and discussion over your favorite draught. In keeping with tradition: here it is 3 more times:
http://www.subsim.com/radioroom/showthread.php?t=112765
http://www.subsim.com/radioroom/showthread.php?t=112765
http://www.subsim.com/radioroom/showthread.php?t=112765

Looking for the guide can someone pm it to me?
I'm working on my file host, sorry.
I will edit it into my original post. I never meant for this thread to become a guide itself, but I dont have any other option.

[Puster Bill]

I figured out how to use the listed methods to calculate a solution when the sub is moving. Its a little more complicated, and involves solving two triangles, from there, I tried a vector-based approach, calculating the subs "trajectory" and the targets, and was able to calculate accurate speeds.

I've actually been meaning to do that myself. I just haven't had the time to sit down and work it out. :damn:

I was going to use the procedure outlined in the instructions for the SACF/IS-WAS at the HNSA site as a basis. I just never seem to get the time to sit down and do it uninterrupted.

[Hitman]

btw, I have to pay my respects to the timeless veterans of the subsim forums, lest I feel the fury of their links. so here's a link I copied off the the image that was burned into my retinas by hitman and puster bill:

http://www.subsim.com/radioroom/showthread.php?t=112765

Its a thread, written by puster bill that describes a method of using a slide rule to calculate target speed, assuming the sub is stationary or at "creeping speed", if you didnt know. It documents historicaly accurate tools and methods, as well as touching on the math involved. A good read for nights by the fire and discussion over your favorite draught. In keeping with tradition: here it is 3 more times:


LOL it's good to see you joined the joke :up:

Seriously now, I have followed your thread with great interest, because -believe it or not- I am a nut in maths (Though I wasn't bad in geometry) and despite having done many slide rulers for SH3-4, it was not easy for me to get the real mathematical formula behind their use. I have been dusting off some of my most buried memories from high school, but I seem to need a good amount of catch-up lessons to be able to get the whole thing again:yep:

Probably that's the main downside of having studied laws at university, where the few maths I knew got fogotten:down:

Anyway, I have been recently coming by research to the method used by the real U-Boot kaleuns in WW2, which involved keeping constant 90º bearing on a target to get both AOB and spee.

What I have been using so far (And was posted by Don1 reed here long ago) is:

By constant 90º/270 bearing:

Sin target AOB : Own Speed = Sin target Speed : Enemy bearing

I have been using a printed table like this


http://img520.imageshack.us/img520/5272/printabletabellenif3.jpg


to get the AOB & Speed by following method:

1- Make two range observations, and measure the time between them

2.- Starting from the top-left (For right AOB) go right as much as your U-Boat advanced. Then go down as much as the target closed in.

The resulting point in the table where it intersects the AOB tells you the result:yep: and you can later apply the above mentioned rule to get speed once you have determined the AOB.

My question is: What would be the exact mathematical formula for this? I mean, there must be a mathematical formula to allow calculating the AOB like that without any table and a finger going right-down on it :roll:

[starvingartist507]

I was going to use the procedure outlined in the instructions for the SACF/IS-WAS at the HNSA site as a basis. I just never seem to get the time to sit down and do it uninterrupted.

I'll have a look at an the Is-Was I downloaded (from subsim forums), and see it involves a relation, or quick-compute way to lay out the data. I dont know if they used a vector system, but it worked for me. I finished that file I mentioned above, it seems to work pretty well, calculating the heading and speed of a target, even when the sub is moving. The math that is going on "in the clockwork" is kind of convoluted, and I'm still trying to trim it down into a simple equation. If someone can do that, they'd have the key to designing the Is-Was, and from there, infinite understanding of its function....So thats what I'm working on!

Also, I had a quick question, can you use an Is-Was when the sub is moving? If so, there most definitely is an underlying relation, and that's pretty much been my holy grail since I bought SH4. Thanks!


Seriously now, I have followed your thread with great interest

Thanks


Anyway, I have been recently coming by research to the method used by the real U-Boot kaleuns in WW2, ...

My question is: What would be the exact mathematical formula for this? I mean, there must be a mathematical formula to allow calculating the AOB like that without any table and a finger going right-down on it :roll:
I'll look at this chart you linked, its very interesting. My german is passable, but I think I get the idea. I assume the U-boat is free to manuever to maintain the 90deg bearing?
Hmm, I'll plug away at it. Thanks for the insight. Thants going to be a few more hours of fun! It doesnt get much more geeky than "fun" math!

Here's a pic of the (extremely junky but funcitonal) program I wrote today to do this math for you. It'll take the place of the stopwatch, basically. If anyone wants to try it, I guess they'll have to PM me with an email address, and I can email it to them. at least until I get my file server back up. I didnt take the time to make an installer for it either, so its just a .rar :-?
http://img360.imageshack.us/img360/7942/tdc1ml1.jpg (http://www.subsim.com/radioroom/%5BURL=http://img360.imageshack.us/my.php?image=tdc1ml1.jpg%5D%5BIMG%5Dhttp://img360.imageshack.us/img360/7942/tdc1ml1.th.jpg%5B/IMG%5D%5B/URL%5D)
edit: pic link was broken
(http://www.subsim.com/radioroom/%5BURL=http://img360.imageshack.us/my.php?image=tdc1ml1.jpg%5D%5BIMG%5Dhttp://img360.imageshack.us/img360/7942/tdc1ml1.th.jpg%5B/IMG%5D%5B/URL%5D)

[Puster Bill]

btw, I have to pay my respects to the timeless veterans of the subsim forums, lest I feel the fury of their links. so here's a link I copied off the the image that was burned into my retinas by hitman and puster bill:

http://www.subsim.com/radioroom/showthread.php?t=112765

Its a thread, written by puster bill that describes a method of using a slide rule to calculate target speed, assuming the sub is stationary or at "creeping speed", if you didnt know. It documents historicaly accurate tools and methods, as well as touching on the math involved. A good read for nights by the fire and discussion over your favorite draught. In keeping with tradition: here it is 3 more times:

LOL it's good to see you joined the joke :up:

Seriously now, I have followed your thread with great interest, because -believe it or not- I am a nut in maths (Though I wasn't bad in geometry) and despite having done many slide rulers for SH3-4, it was not easy for me to get the real mathematical formula behind their use. I have been dusting off some of my most buried memories from high school, but I seem to need a good amount of catch-up lessons to be able to get the whole thing again:yep:

Probably that's the main downside of having studied laws at university, where the few maths I knew got fogotten:down:

Anyway, I have been recently coming by research to the method used by the real U-Boot kaleuns in WW2, which involved keeping constant 90º bearing on a target to get both AOB and spee.

What I have been using so far (And was posted by Don1 reed here long ago) is:

By constant 90º/270 bearing:

Sin target AOB : Own Speed = Sin target Speed : Enemy bearing

I have been using a printed table like this


http://img520.imageshack.us/img520/5272/printabletabellenif3.jpg


to get the AOB & Speed by following method:

1- Make two range observations, and measure the time between them

2.- Starting from the top-left (For right AOB) go right as much as your U-Boat advanced. Then go down as much as the target closed in.

The resulting point in the table where it intersects the AOB tells you the result:yep: and you can later apply the above mentioned rule to get speed once you have determined the AOB.

My question is: What would be the exact mathematical formula for this? I mean, there must be a mathematical formula to allow calculating the AOB like that without any table and a finger going right-down on it :roll:

Hey, Hitman, have you considered doing a 'Super Targeting Toys/Tutorial' pack?

You've built enough, and done enough research, that putting it all together in a single, large package seems the logical thing to do. Certainly, I'd be interested in it.

I know it's a lot of work, and you have done more than your share of work for this community to get that stuff out there, but I know that I and many like me would be interested in it presented as a single coherent set of tools and instructions, perhaps with a couple of examples and the theory behind them, instead of chasing them down here and there all over Subsim.

Like I said, you've done more than enough, so I feel guilty even mentioning it, but it certainly would be helpful for us mere mortals...

[Xelif]

Starvingartist, could you elaborate a little bit about the trig method you used to solve a solution where your sub is moving? You said you solve two triangles... I've got a very rough idea and if you felt like going into the formulas briefly, I'd appreciate it.

[Hitman]

Also, I had a quick question, can you use an Is-Was when the sub is moving? If so, there most definitely is an underlying relation, and that's pretty much been my holy grail since I bought SH4. Thanks!


Yes it has a "Speed correction" feature:up: where you substract your own ship's speed, recalculated to make sense to the observed enemy ship speed.

Thants going to be a few more hours of fun! It doesnt get much more geeky than "fun" math!


LOL we are real "Frikkies" ain't we? :lol: When I just think that I hated maths back in school :damn: If the maths and physics teachers (BTW I studied at the german school in Valencia-Spain) had used nice examples like U-Boots, Guns, Automobiles and such instead of the idiotic ones they used, I bet many more would have got hooked by maths :shifty:

I'll look at this chart you linked, its very interesting. My german is passable, but I think I get the idea. I assume the U-boat is free to manuever to maintain the 90deg bearing?
Hmm, I'll plug away at it. Thanks for the insight. Thants going to be a few more hours of fun! It doesnt get much more geeky than "fun" math!

Here's a pic of the (extremely junky but funcitonal) program I wrote today to do this math for you. It'll take the place of the stopwatch, basically. If anyone wants to try it, I guess they'll have to PM me with an email address, and I can email it to them. at least until I get my file server back up. I didnt take the time to make an installer for it either, so its just a .rar :-?


Yes the U-Boot is free to move, and what it does is change course/speed in a way that keeps the enemy at constant bearing.

The idea is to build a constant triangle with a 90º angle on it (At the corner of your U-Boot), that allows you to apply the law of Sines for getting speed, as the constant bearing neutralizes the dynamic aspect of speed (Time/Distance) and makes of it an absolute value.

What the tables do is basically build abother triangle A,B,C with a 90º degree on it like this:

A\
I \
I \
I \
I \
B___ \C

Where B-C represents the target distance covered forward (Obtained from your U-Boots own forward movement during the time measured), and A-B the distance the enemy has closed in (Obtained from the two range measurements). While the table gives you a quick visual solution, there is of course a mathematical formula behind all that, which takes into account the triangle. Since we know the lentgh of two of the sides of that triangle (And we could also get the length of the third by the Phytagoranian a2+b2=c2, but we don't need it) and one angle (90º) we should be able to calculate mathematically the other two by a formula using the Sine and Cosine....only that I don't remember any more how it was done, despite having done that back in school long ago :damn:

Here's a pic of the (extremely junky but funcitonal) program I wrote today to do this math for you. It'll take the place of the stopwatch, basically. If anyone wants to try it, I guess they'll have to PM me with an email address, and I can email it to them. at least until I get my file server back up. I didnt take the time to make an installer for it either, so its just a .rar :-?


Sure! I'll PM you in a moment with some interesting stuff and a e-mail address:up:

Hey, Hitman, have you considered doing a 'Super Targeting Toys/Tutorial' pack?

You've built enough, and done enough research, that putting it all together in a single, large package seems the logical thing to do. Certainly, I'd be interested in it.

I know it's a lot of work, and you have done more than your share of work for this community to get that stuff out there, but I know that I and many like me would be interested in it presented as a single coherent set of tools and instructions, perhaps with a couple of examples and the theory behind them, instead of chasing them down here and there all over Subsim.

Like I said, you've done more than enough, so I feel guilty even mentioning it, but it certainly would be helpful for us mere mortals...

Yes, more or less...

I have been collecting data and historical research in order to make somewhen a manual of the historical procedures used in german U-Boots. There is in fact no need to do something like that for US subs, as it is well documented, but german U-Boot information seems to have got lost after the war :hmm: It's a fascinating job to actually research and investigate this mistery, collecting here and there pieces of the puzzle, and I think the job is also worth it, because the methods used were very simple and with no plotting involved (Everything was done with wiz-wheels and printed tables), something that would suit perfectly a SH3 player, who is alone while playing (Not assisted by a fire control party).

What I'm currently doing is still collecting stuff (Have already tons of it, but not many form authentic sources) and doing concept sketches in paper, then testing them in SH3 to check the efectiveness.

I started following this thread with great interest because of course I wanted to explain in the manual the real maths behind all that, not just the use of wiz-wheels and tables:up:

Anyway, I'm not in a hurry with this, it's becomed a long term project and I want it also to be a contribution for the opensource sim "Danger of the Deep"

[starvingartist507]

Ok, here's how the math works with the Tabelle:

The first thing I noticed is they set the U-boat speed to very slow rate (no respectable merchant is going to go 2-3 knots), this is so they don’t go faster than the target, effectively circling around them as they try to keep a constant bearing.

With the U-boat at a slower speed, and keeping a constant bearing, I get the following graph.
http://img440.imageshack.us/img440/1985/tabellegraphjc5.jpg

Basically, this chart doesn’t use Sin curves at all. I just says that, if a=b, then AOB has to be 45deg, because we have a standard right triangle with two equal legs.

This chart asks you to figure out the values for (a) and (b), then simply shows you their ratio. If the ratio is 1:1, then the angle is 45deg. If the ratio is a little bit less, then the angle decreases by an equivalent amount. If the ratio is more, well it increases by the same amount. This is a very neat way to figure AOB, in my opinion. Interestingly, if you want to find their speed, just use the Pythagorean Theorem to find the distance traveled (c), divide by seconds, and multiply by 1.777. No messy business with Sin curves or anything like that.



Resourceful krauts!


http://img215.imageshack.us/img215/691/printabletabellenif3iv9.jpg

[starvingartist507]

Looking for the guide can someone pm it to me?
Starvingartist, could you elaborate a little bit about the trig method you used to solve a solution where your sub is moving? You said you solve two triangles... I've got a very rough idea and if you felt like going into the formulas briefly, I'd appreciate it. Sorry to you and others that have asked for the guide. It is now available at
www.hoofinasia.net (http://www.hoofinasia.net)

I have updated my original post to reflect this.

I'm off to work on the is-was.

EDIT: just figured out the is-was, I'll post the math in a second.

[starvingartist507]

So here's the simplified relation to find merchie speed, even when the sub is moving.

DM=distance merchant traveled (unknown)
DS=distance sub traveled --> (sub speed in knots / 1.777) x seconds
B1=bearing 1
R1= range 1
B2= bearing 2
R2= range 2


[ ((Sin B1) x R1) - ((Sin B2) x R2) ]squared
+
[(DS)- ((Cos B1) x R1) - ((Cos B2) x R2) ]squared
=
[DM] squared
solve for DM, (remember to take the square root of everything...) divide by seconds, mulitply by 1.777, there's your speed. Thats actually a pretty simple equation, and works if the sub is moving or not. So there it is, in case you have a morbid fascination with math.

I'm going outside.

[Xelif]

You are my hero, starvingartist :D

Thank you for taking the time to painstakingly illustrate and explain these ideas!

[Hitman]

Basically, this chart doesn’t use Sin curves at all. I just says that, if a=b, then AOB has to be 45deg, because we have a standard right triangle with two equal legs.

This chart asks you to figure out the values for (a) and (b), then simply shows you their ratio. If the ratio is 1:1, then the angle is 45deg. If the ratio is a little bit less, then the angle decreases by an equivalent amount. If the ratio is more, well it increases by the same amount. This is a very neat way to figure AOB, in my opinion.

Thanks for your explanation:up: However, I *think* you do have to use the Sine at one point for doing it with an equation: The proportion 1:1 is only correct for the 45º angle, but if my thoughts are right, the rest of the angles will not follow a linear or aritmetical proportion (F.e. a proportion of 70% height vs. length is NOT 70º AOB but rather 45º) but instead a sine curve one:hmm: Am I right?

Interestingly, if you want to find their speed, just use the Pythagorean Theorem to find the distance traveled (c), divide by seconds, and multiply by 1.777. No messy business with Sin curves or anything like that.


Yup good catch:up: Though it can be also determined with Sines, of course. Interestingly, the quickest method is very different when using a slide ruler or pure algebra. With a Slide Ruler using Sine is way faster, while you are completely right in that using just algebra solving the problem with Sines would be an unnecessary waste of time.

But that's the lovely part of maths: Many times you can do the same thing by different ways:|\\ and you can then choose which ones fits better your real purpose:yep:

[starvingartist507]

Basically, this chart doesn’t use Sin curves at all. I just says that, if a=b, then AOB has to be 45deg, because we have a standard right triangle with two equal legs.

This chart asks you to figure out the values for (a) and (b), then simply shows you their ratio. If the ratio is 1:1, then the angle is 45deg. If the ratio is a little bit less, then the angle decreases by an equivalent amount. If the ratio is more, well it increases by the same amount. This is a very neat way to figure AOB, in my opinion.
Thanks for your explanation:up: However, I *think* you do have to use the Sine at one point for doing it with an equation: The proportion 1:1 is only correct for the 45º angle, but if my thoughts are right, the rest of the angles will not follow a linear or aritmetical proportion (F.e. a proportion of 70% height vs. length is NOT 70º AOB but rather 45º) but instead a sine curve one:hmm: Am I right?



Yes, thats true. The equation involves a trig function, so obviously the relationship would be a curve, silly me. :oops:

Here's the equation that the card used. The Trebelle basically estimated the answers for this:

inverse Tangent of (distance sub traveled / range difference). There are extenuating circumstances, but thats the basic idea.

[jmr]

http://img520.imageshack.us/img520/5272/printabletabellenif3.jpg



Is there a larger version of this chart available?

[MudMarine]

Basically, this chart doesn’t use Sin curves at all. I just says that, if a=b, then AOB has to be 45deg, because we have a standard right triangle with two equal legs.

This chart asks you to figure out the values for (a) and (b), then simply shows you their ratio. If the ratio is 1:1, then the angle is 45deg. If the ratio is a little bit less, then the angle decreases by an equivalent amount. If the ratio is more, well it increases by the same amount. This is a very neat way to figure AOB, in my opinion.
Thanks for your explanation:up: However, I *think* you do have to use the Sine at one point for doing it with an equation: The proportion 1:1 is only correct for the 45º angle, but if my thoughts are right, the rest of the angles will not follow a linear or aritmetical proportion (F.e. a proportion of 70% height vs. length is NOT 70º AOB but rather 45º) but instead a sine curve one:hmm: Am I right?



Yes, thats true. The equation involves a trig function, so obviously the relationship would be a curve, silly me. :oops:

Here's the equation that the card used. The Trebelle basically estimated the answers for this:

inverse Tangent of (distance sub traveled / range difference). There are extenuating circumstances, but thats the basic idea.

This is one good ole boy who sqeaked by with Algebra 1. I am gona have ta take a trig course for dummies. This here might just get me edjamacaded. Harder ta shot a torpedo than shooten a dang rifle. I guess the same principles apply windage, elevation and lead on a moving target. A whole new world this Boat sim.
My hats of ta Annapolis graduates. That dang shinny ring means somethin. It got me lookin at a circular slide rule and I built one from;

Build your own slide rule
http://www.sphere.bc.ca/test/build.html

Just takes time ta sink into this thick Jarheads head. That brain housing a bit rusty.
It's no longer just bein a hat rack. I feel a head aches a comin on just thinkin about trig.:damn:

[Hitman]

Is there a larger version of this chart available?

Not yet. That one I made as a Beta for personal use, and the numbers below the graphics come from work done by an artist whose permission I have not yet asked for. I posted this reduced quality image to show the example to Starvingartist and make the idea understandable, but I didn't want anyone to start doing screen captures of it and using/making it public until I do the job correcty and see if I will incorporate graphics from others and thus ask permission for it :hmm:

So...when its done...I will release it :ping:

Here's the equation that the card used. The Trebelle basically estimated the answers for this:

inverse Tangent of (distance sub traveled / range difference). There are extenuating circumstances, but thats the basic idea.

Yes, exactly that's what I was looking for. That's the mathematical formulation I intuitively knew should be there but couldn't figure out :up: Thanks:|\\

[Puster Bill]

Basically, this chart doesn’t use Sin curves at all. I just says that, if a=b, then AOB has to be 45deg, because we have a standard right triangle with two equal legs.

This chart asks you to figure out the values for (a) and (b), then simply shows you their ratio. If the ratio is 1:1, then the angle is 45deg. If the ratio is a little bit less, then the angle decreases by an equivalent amount. If the ratio is more, well it increases by the same amount. This is a very neat way to figure AOB, in my opinion.
Thanks for your explanation:up: However, I *think* you do have to use the Sine at one point for doing it with an equation: The proportion 1:1 is only correct for the 45º angle, but if my thoughts are right, the rest of the angles will not follow a linear or aritmetical proportion (F.e. a proportion of 70% height vs. length is NOT 70º AOB but rather 45º) but instead a sine curve one:hmm: Am I right?


Yes, thats true. The equation involves a trig function, so obviously the relationship would be a curve, silly me. :oops:

Here's the equation that the card used. The Trebelle basically estimated the answers for this:

inverse Tangent of (distance sub traveled / range difference). There are extenuating circumstances, but thats the basic idea.
This is one good ole boy who sqeaked by with Algebra 1. I am gona have ta take a trig course for dummies. This here might just get me edjamacaded. Harder ta shot a torpedo than shooten a dang rifle. I guess the same principles apply windage, elevation and lead on a moving target. A whole new world this Boat sim.
My hats of ta Annapolis graduates. That dang shinny ring means somethin. It got me lookin at a circular slide rule and I built one from;

Build your own slide rule
http://www.sphere.bc.ca/test/build.html

Just takes time ta sink into this thick Jarheads head. That brain housing a bit rusty.
It's no longer just bein a hat rack. I feel a head aches a comin on just thinkin about trig.:damn:

That was close. I thought you were going to link to the thread-that-shall-not-be-linked-to.

If you are serious, though, go ahead and get Hitmans backside to the Submarine Attack Course Finder/IS-WAS-WILLBEAGAIN. Then read either the instructions in the TTSNBLT, or to the document at HNSA that describes how to use it. You will find it more intuitive and less 'mathy' than a plain slide rule, although I use a small pocket slide rule for occasions when playing might be seen as non-productive, if you get my drift.

[starvingartist507]

That was close. I thought you were going to link to the thread-that-shall-not-be-linked-to.


Thank God!