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-   -   target speed: the eighty-ten method (https://www.subsim.com/radioroom/showthread.php?t=173086)

greyrider 09-04-10 10:26 PM

Quote:

Originally Posted by Nisgeis (Post 1484132)
It's been over a month since this tread was started and since that time greyrider has failed to address the central issue that ha been asked about, namely the problem of 'knowing the AoB is 10 degrees'. He just refers us to other posts which don't contain the answer either and posts with increasing length and reducing content. I don't think we should hold our breath.

Greyrider, if you are interested in getting people to use this method, you need to answer the simple question of 'How do you know that the AoB is 10 degrees, or what problems will you have if the AoB is not 10 degrees.' It's been asked many times and you have never answered it.

maybe i have failed in getting it thru, for that im sorry, ill try to say it again, the torpedo fire control manual states it only has to be held constant for 2 or 3 minutes, if it said it had to be held indefinitely, it would have said so, but it doesnt, so in the eyes of the tfcm, 2 or 3 minutes of the target being held at a bearing, any bearing, is good enough for an accurate speed estimation. i put up some pics of the angles as they are seen on the sh4 editor map, didnt you see them? you could put them in paint, rotate them, measure the angles with a compass from a pencil box, and see they are. and ive done it thousands of times, only for the most part of playing this game, i never new the sizes of the angles, because i never measured them before.

greyrider 09-04-10 10:47 PM

Quote:

Originally Posted by joegrundman (Post 1483966)
i've listened to the sinking from the kongo - it's available from hnsa. it was indeed tracked by radar. There was i believe no overhaul, since a submarine overhauling Kongo and some DDs at full speed, if even possible, would be overhauling at about 1 knot per hour.

It took an hour if i recall for the kongo to sink, refusing at first to drop below 15 knots for fear of further torpedo attacks. 15 knots after being hit 3 times suggests that an overhaul was not likely before the attack.

This was not a point and shoot attack, nor an 80/10 attack (not that such a thing exists). All the data was gathered from radar, and a spread was fired scoring 3 hits. The insertion of the data was into the TDC which calculated the lead angles, and the shots were made. No magic, no special techniques.

This text of yours, while interesting, has no bearing at all on the discussion in this thread


joe, thanks for the imput, i was wondering where you were.
i read that story to, and i listened to those records a couple of times, thats where i heard them mention width, target width, but i never heard or read anything about a spread. my post on sealion, i said it was pretty obvious it was a radar plot, they had everything worked out by 32000 yards.
however, it says alot about risk, and zig zagging, reich took a big risk,
one near miss from yamoto, and sealion was gone, reich didnt know yamoto was there, but he knew 2 ships of battleship proportion and two of large cruiser size were there, hes a navy man, and knows the power of those guns on those bb's. and then he had to worry about destroyers,
and the sea going down the hatch short circuiting every thing, it was solid water, in a storm of wind, at night.

a spead is a lucky shot,when the solution is in doubt and that is like calling reich a lucky man that night, i like to think him better than lucky, engines straining, solid water down the hatch, gale winds, formidable enemy formation, luck could be said for sealion, but hears the thing, at present theres no proof, one way or another about that.

i guess he must of thought the risk was worth it.
dont think any of the crew complained.

greyrider 09-05-10 12:05 AM

i dont want to get off topic, especially since the complaints about me not being clear to you, still has you confused. remember what i said, no arm twisting here,
do as you wish, in fact, i would like you to forget it, its useless to anyone but me. i use it with success.
im not trying to get anyone to use 8010, im just showing a tactic, that i use. i now think you will never understand it. its your loss guys, not mine,
theres nothing like the feeling of tracking this way, and killing, and ill put my map skills against anyone here, but this is alot better in my opinion, but sometimes the map is needed, plotting is needed sometimes.
8010 is a simple procendure, the turn takes care of course and aob. at a certain angular arrangement speed can be taken accurately, its that simple for me, i dont know how simple it will be for you,
but i know one thing, its a matter of skill, you either have it or you dont, that simple, theres no other excuse.
When a submarine submerges, radar becomes useless and no lookouts remain on deck. The periscope and the sonar gear are now the eyes and ears of the submarine. But in the vicinity of enemy ships, it may be dangerous to use the periscope very often. Then the submarine must depend chiefly on listening. The sonar operators become the main channel of
information about the maneuvers of the enemy
The fact that the speed of sound varies, especially with temperature, explains why sound waves are bent out of their normal paths. This bending is called refraction. Usually water is warmer near its surface than at lower depths. As shown in the diagram at the right, the upper part of a sound wave in the warmer water travels faster than the lower part in the colder water.
This makes the sound wave bend downward. the bending you could say is vertical, not horizontal. sound travels in a three sixty.
on american submarines, they had whats called the magic eye.
the Magic eye indicator lets the operator's eye see what his ears hear. The eye closes when current is strongest,
on american submarines, with a magic eye, there was never any doubt about what bearing the target was on.
in this picture of the hydrophone electronics, you have two stages of amplifiers, that amplify the sound signal, its then wired to five filters, in which, one, two, 3, 4 or all five filers can be turned on separately or all at once.
these filters pass certain freguencies, and block others.
the voltage is then adjusted by a potentiometer, current is proportional to voltage, into two more amplifiers, coming out to a propeller counter, to another amplifier, to a speaker or headphones for listening.
another circuit from the output amp, goes to another potentimeter, for voltage adjustment, into another amplifier, another filter, probably to attenuate noise, to a rectifier, to drive the magic eye. this rectifier is probably
rectifing the alternating current signal, since sound is ac, into direct current or dc, to drive the magic eye indicator that would let u s sonarmen, know exactly what bearing the target was on. they didnt have to do it like i did in the movie,
because us sonar is misrepresented in the game. what i did was conpensate for not having a magic eye.
http://a.imageshack.us/img715/8823/fig16a.jpg
By null at 2010-09-04
http://www.maritime.org/fleetsub/sonar/chap4.htm

tater 09-05-10 12:55 AM

You still have not answered the question; How do you know the AOB is 10?

What you are doing is making an assumption about the AOB of the target, which then gives you a speed for that assumption. If the AOB happens to be within some small range of 10 by accident, then you'll get an estimate of speed commensurate with the difference. Pick narrow seas to hunt, and maybe you can limit their courses so that the estimate won't be crap.

Your triangle is a projection of the target's path onto an arbitrary line perpendicular to the path of the sub. In simple terms, it's a shadow.

Pisces 09-05-10 07:01 AM

Quote:

Originally Posted by greyrider (Post 1485273)
maybe i have failed in getting it thru, for that im sorry, ill try to say it again, the torpedo fire control manual states it only has to be held constant for 2 or 3 minutes, if it said it had to be held indefinitely, it would have said so, but it doesnt, so in the eyes of the tfcm, 2 or 3 minutes of the target being held at a bearing, any bearing, is good enough for an accurate speed estimation. i put up some pics of the angles as they are seen on the sh4 editor map, didnt you see them? you could put them in paint, rotate them, measure the angles with a compass from a pencil box, and see they are. and ive done it thousands of times, only for the most part of playing this game, i never new the sizes of the angles, because i never measured them before.

This comes down to a bearing rate that has to be below 0.333 degrees per minute to be considered on a constant bearing. If you do the math, a target running circles around you at the edge of hydrophone range at 6.4 knots would also be considered to be on a collision course. Surely you see the error in the assumption that it is colliding, right? If it is written in the Torpedo Fire Control Manual (and it is, I read it), then it is writing BULL. (Yes, I know sacrilege :arrgh!:) ANY target will appear to be not drifting in bearing if it is sufficiently distant. At some distance the drift will not be measurable, like the 1 degree limit of the hydrophone. Yet it still moves with some speed across the line of sight. Even if it is at the point where it has 90 degrees AOB, where the bearing drift is at maximum. Even if it moves at light-speed across the line of sight. Holding onto the 3-minute constant-bearing rule you'd start to wonder when the minor-planet Pluto starts crashing onto us. It's not drifting (it takes 248 years to go around the sun), so collision is inevitable! Wrong. Long distance hides the fact that it is drifting in bearing.

If we take your 80-10(-90) triangle as given, and assume the target is detected at maximum long-range (10.8nm). And the drift stays under 1 degree in 3 minutes. It may have a speed-advantage across the line of sight (meaning over your speed*sin(80)) of 3.77 knots to still be considered constant bearing. This could be a 12 knot target that really has an AOB of 18.3 degrees if you are not moving. Or it has an AOB of 28.5 when you think you have a constant bearing and while you are moving 2 knots with 80 degrees lead. So, assuming the AOB is 10 degrees is very questionable at best. But no matter, as those will get eliminated pretty soon from the target-pool.

Why? Well, the closer the target comes, the more their bearing rate increases. So quite quickly those 3.77 knots across the line of sight will appear to be a target that is either going too fast or has to high AOB. The targets that have a smaller AOB, more akin to 10 degrees, will last longer under your presumption of a constant bearing. But eventually are evicted too

At minimum-longrange (1.62nm) the target may not have a bigger speed advantage across over yours of 0.56 knots to comply with the 3 minute constant bearing rule. This means an AOB of 2.67 degrees if you are not moving yourself. Or an AOB of 12 degrees if you think you have a constant bearing and are moving with 2 knots and 80 degrees lead. The conclusion is that only those targets that already conform to your 10 AOB rule survive until the end. Those that are not, and I'd think A LOT, get discarded before hand. Well, you allready stated in one of the earlier replies to us that many are left alone. But I really wonder how many you let go, before you find one that matches your presumptions. Please give us some (rough) statistics.

Either-way, this method turns out to be nothing but a filter for 10 AOB. You get what you want to see. Everything else gets thrown out. Don't be fooled into thinking 10 AOB is a rule.

joegrundman 09-05-10 07:27 AM

3 minutes to determine a collision course is ok at medium range. at long range you need much longer. In the torpedo fire control manual, for this technique (which is really a pre-ww2 technique) it already assumes you have visually determined AOB, and so is most likely at medium range.

But in general the tolerance of error was much greater than is expected in this game. They made up for it with firing torpedoes in a wide spread (see above with the kongo where 6 were fired, 3 hits, by definition it was a spread covering a wider area than the target) and getting close to the target.

See also the TFCM section on early TMA based on bearing rate analysis - they estimated 2 mins was sufficient for a new solution!!

Finally, misses were more likely when radar was not employed.

Also: i don't know how often i have to say this until somebody here decides to study this further, but read the 1922 guide to the Submarine Attack Course Finder, which is designed to be used with the correct collision course technique that Greyrider has failed so far to replicate.

http://www.hnsa.org/doc/attackfinder/index.htm

Pisces 09-05-10 10:45 AM

Quote:

Originally Posted by joegrundman (Post 1485422)
3 minutes to determine a collision course is ok at medium range. at long range you need much longer. In the torpedo fire control manual, for this technique (which is really a pre-ww2 technique) it already assumes you have visually determined AOB, and so is most likely at medium range.

I suspected that visual contact made was implied. And wondered why it wasn't explained to be bounded by that condition. Surely they must have known better. But I guess I missed it being described as part of the "Approach and Attack" phase. In this context I can agree that it is 'constant enough', but Greyrider's use of it is not warranted.

On a side note. Is there a pdf version of these manuals that do not waste so much paper space in the margins. Or does not have continuous pages. The hnsa.org layout is much to slender to print out. And I'd love to read it on paper. I know these things are for sale somewhere but I'm not that eager.

greyrider 09-05-10 11:33 AM

ok, where theres a will, theres a way, and i have the will,
so you ask for proof its a ten degree aob in 8010, coming right up!
im going to show you 3 pictures, of a mission, this time at 0 percent realism,
im going to make auto-tdc prove its a ten degree aob, with lead angle of 80 degrees.
the first picture is what you see if you open this mission in sh4 editor map.

http://a.imageshack.us/img521/1870/checkangles.jpg
By null at 2010-09-05


one ship is on bearing 271, another ship is on bearing 280, since this is auto tdc,]
you should be able to read the aob, on the dial in the upper right corner.
in picture number 1, the target is at 271, it has a 1 degree aob, i tried to get it on 270 for a zero degree aob, but i was alittle off.
it doesnt matter, the aob is 1 degree, plainly seen in the dial.

http://a.imageshack.us/img521/408/88099779.jpg
By null at 2010-09-05

in picture two, the target is in an 8010, it bears on 280, notice the aob in auto tdc, whats it say?
10 degree aob.

http://a.imageshack.us/img521/6550/59232177.jpg
By null at 2010-09-05

enjoy!

greyrider 09-05-10 11:47 AM

one more pic, this time from the merchant pov
http://a.imageshack.us/img819/5972/s...0512402583.jpg
By null at 2010-09-05

Nisgeis 09-05-10 11:57 AM

I only have one face and two palms. I never before had the feeling that wasn't enough.

razark 09-05-10 12:13 PM

Yes, you've once again shown you know the property that the three angles of a triangle add up to 180 degrees.

You have yet to prove the triangle is a right triangle, based only on knowing that one angle is 80 degrees.

The submarine is on a heading of 0 degrees. It's a right triangle only because you've set it up that way.

If the target were heading 90 degrees, as in your example, and the submarine was on a heading of 45 degrees, and the bearing to target were 80 degrees, find the AoB.

tater 09-05-10 12:20 PM

Quote:

Originally Posted by Nisgeis (Post 1485597)
I only have one face and two palms. I never before had the feeling that wasn't enough.

BTW, you owe me a keyboard (or a way to get coffee out of it ;) ).

Pisces 09-05-10 12:31 PM

Quote:

Originally Posted by Nisgeis (Post 1485597)
I only have one face and two palms. I never before had the feeling that wasn't enough.

Ok, please explain that to non-native american (and I do not mean 'indians') readers. I'm missing your point, ... though I probably agree.

joegrundman 09-05-10 12:37 PM

for pisces:

http://i297.photobucket.com/albums/m...r/facepalm.jpg


greyrider:

no one is doubting you can set it up this way. the problem is the assumption that any encounter will necessarily conform to this pattern. It will not, unless you know already the true course of the target.

If you are able to eyeball the aob than that is enough, but you can't know aob in advance from this method.

part of the problem greyrider is that you are a highly experienced player with a lot of ability to visually estimate speed, range and aob, and it is my guess that you rely on visual estimates to correct errors in your theory, without appreciating you are doing so.

joegrundman 09-05-10 12:54 PM

Quote:

Originally Posted by Pisces (Post 1485559)
On a side note. Is there a pdf version of these manuals that do not waste so much paper space in the margins. Or does not have continuous pages. The hnsa.org layout is much to slender to print out. And I'd love to read it on paper. I know these things are for sale somewhere but I'm not that eager.

you can copy and paste into a word document then save as pdf and print. should only take a few minutes to remove the unwanted stuff


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