Finding AOB/speed from map

[patio87]

I searched but had a hard time finding anything good. What I am wondering is how do I determine AOB by just using map contacts. I remember seeing that you could put down the angle between your ship and the conact, but I don't remember the specifics.

Also how can I determine the speed this way?

And what exactly are the marks on the scopes used for, can I use those to help determine speed, or height/distance of a target?

[sckallst]

Once you know the target's true course, setting AOB in the TDC is easy.

Look at the 'target' portion of the TDC (the upper guage of the TDC). The outer ring of numbers surrounding the target boat indicator represents the 'true' course of the target. Now bring up the data input device. Turn the AOB setting dial in the input device, imagining that you are turning the target boat indicator on the TDC. Just turn the input device so that the TDC target boat will be pointed along its true course on the TDC as defined by the TDC outer ring. Enter that AOB position in the data input device, then fine tune as needed.

There are other ways to guess at AOB by eyeballing the target, figuring out aspect ratios and the like, but with map contacts on, the easiest is to simply take a couple of target position readings, draw a line between the two and then simply determine the target's course. Those same two data points will also provide you with the target speed, or at least a good first estimate. Keep monitoring the target and fine tune your numbers from there.

There are a whole bunch of good threads (and video tutorials) with answers to the rest of your questions, and lots of good folks around to help.

[Arclight]

You can use the protactor (triangle) tool on the map to measure angles. Click in front of your target, then on your target and then on your sub. You should now have one leg extending in front of your target representing it's course, the angle part on your target and a leg extending from the target to your sub. The angle shown is the OAB.

Speed can be determined by placing a mark on your target and starting the stopwatch. Let it run for 3 minutes and place another mark on your target. Measure the distance traveled in yards and divide by 100; 700 yards = 7kts, 1100 yards = 11 kts, etc.

Can't for the life of me remember the exact formula, forgot after installing RFB. I'm sure someone will barge in here to clarify and fill in the details. ;)

You can determine speed from the scope, but this is beyond me. The marks are 4deg for the large ones and 1 deg for the small ones in low magnification, 1deg / 0.25deg in high magnification. Personally I only use them to determine a good angle to use with the offset dial for a nice spread.

[Rockin Robbins]

I refer you to the Dick O'Kane Targeting Video (http://files.filefront.com/Dick+OKane+targeting+video7z/;10643361;/fileinfo.html), which will cover determining course and speed of the target with the nav map. Unfortunately, with the Dick O'Kane method, measuring AoB is not necessary so you won't find any pointers on that.

You also won't find any pointers on target identification manual or stadimeter use because we threw both of them in the deepest part of the Pacific we could find. http://i196.photobucket.com/albums/aa293/RockinRobbins13/smileys/kicking.gif

[Arclight]

"I'm sure someone will barge in here to clarify and fill in the details."

See? Everytime someone writes that, RR comes charging in to save the day with a link to a tutorial. :lol:

It's like raising a flag, or sounding a horn. :lol:

[Rockin Robbins]

CChhaaarge!!!!
http://i196.photobucket.com/albums/aa293/RockinRobbins13/smileys/roflmao.gifhttp://i196.photobucket.com/albums/aa293/RockinRobbins13/smileys/roflmao2.gifhttp://i196.photobucket.com/albums/aa293/RockinRobbins13/smileys/hilariouslaughing.gif http://i196.photobucket.com/albums/aa293/RockinRobbins13/smileys/muhaha.gifhttp://i196.photobucket.com/albums/aa293/RockinRobbins13/smileys/hilariouslaughing.gifhttp://i196.photobucket.com/albums/aa293/RockinRobbins13/smileys/roflmao2.gifhttp://i196.photobucket.com/albums/aa293/RockinRobbins13/smileys/roflmao.gif

[Squid95]

I too once worried about such details as AOB and the PK and the %$#@! stadimeter until I discovered the Dick O'kane method via RR's great tutorial ( many thanks), since then I have not looked back.

Shoot everything 90 degrees to target track, if you want to lead the target by say 10 degrees (before it crosses 0 degrees relative) just remember to adjust AOB by 10 degrees, click twice and update bearing by clicking range twice, done.

I am fully confident of shooting even at ranges over 2000 yards, of course that all fails when the target sees your fish's wake, just attack at night. Another thing I love about this method is the amount of acceptable error, even your course estimation is off by a few degrees your probably still gonna hit, speed is really the key element. I shoot fish with reckless abandon now. Fire and forget.

Now trying this method with sonar only, more art than science but fun to try.

[Pisces]

Speed can be determined by placing a mark on your target and starting the stopwatch. Let it run for 3 minutes and place another mark on your target. Measure the distance traveled in yards and divide by 100; 700 yards = 7kts, 1100 yards = 11 kts, etc.

Can't for the life of me remember the exact formula, forgot after installing RFB. I'm sure someone will barge in here to clarify and fill in the details. ;)1 nautical mile is about 2000 yards long (give or take 1%). So 1 naut'/hour is the same as 2000 yards/hour. Then in 3 minutes (which is 1/20th of an hour) it would have moved 100 yards. So, i.e. in the same 3 minute time a 7 knot target has moved 700 yards. If you need to work with (kilo)meters and knots it's about 3m15s instead of 3 minutes.

You can determine speed from the scope, but this is beyond me. The marks are 4deg for the large ones and 1 deg for the small ones in low magnification, 1deg / 0.25deg in high magnification. Personally I only use them to determine a good angle to use with the offset dial for a nice spread.You can use the scope to get speed but not with those marks. They are really to be used for measuring sizes I think, although not of much use ingame. (Hitman has a cool tutorial somewhere to get AOB with it) The trick to get speed is to make an imaginary motionless 'line' or perhaps better 'wall' through the sea with your vertical periscope line. You take the time a ship needs to move through this 'wall' from bow to stern (on it's own speed) and based on it's real length (ID required) you convert that into a speed (yds/sec -> naut's/hour). The requirement is only that you must keep that imaginary wall from moving sideways. If your periscope is looking sideways, and you are moving forward/backward this 'wall' also move sideways because of that, and so you distort the measurement. You must turn your sub towards or away from the ship to avoid this, or be at standstill. (and so the ship will be seen at 0 or 180 degrees too) For best accuracy do both. It doesn't really matter how the ship is oriented (AOB) as the speed will be the same no matter what. It is just difficult to time the moment of bow and stern passage when the AOB is near 0 and 180 degrees (ship-parts are hidden from view and only a few pixels appart). Around an AOB of 90 degrees is better but definately not a requirement.

[Mush Martin]

This is my preferred method of prosecution.:yep:

[Arclight]

Thanks Pisces, that's certainly good knowledge to have. :)

Now just to get my hands on some charts containing the length for every ship. Aren't there some mods out there that add ship length to the recog. manual? :hmm:

I'm afraid I've gotten lazy in my calculations and formulas since RFB; it provides what I need on the map (nomograph, is it?)....
Shoot everything 90 degrees to target track, ...You should try that with RFB. :lol:

I think you'lld find that the duds are of the charts with such strikes (I did :-? ).

[Squid95]

Thanks Pisces, that's certainly good knowledge to have. :)

Now just to get my hands on some charts containing the length for every ship. Aren't there some mods out there that add ship length to the recog. manual? :hmm:

I'm afraid I've gotten lazy in my calculations and formulas since RFB; it provides what I need on the map (nomograph, is it?)....
Shoot everything 90 degrees to target track, ...You should try that with RFB. :lol:

I think you'lld find that the duds are of the charts with such strikes (I did :-? ).

Excellent point, I can usually avoid the firing pin problem with a slight angle, like 10 to 15 degree lead.

[Arclight]

Probably the best solution as well. :)

Even when setting the buggers to run slow they tend to go dud at a 90deg angle. Wouldn't believe the number of torpedos I wasted on stationary cripples, trying to finish them off. Learned to pack a couple of mark 10s for this occasion the hard way. :shifty:

[Munchausen]

Excellent point, I can usually avoid the firing pin problem with a slight angle, like 10 to 15 degree lead.

:hmm: Actually, leading the target should make the firing pin problem worse. Take a look at the green line on your attack map after you've set up your solution ... leading a target usually means it will hit closer to 90 degrees.

If you fire as the target reaches the 90-degree point, it is already at ... er, at 90 degrees. Ergo, by the time the torpedo hits, it will be striking the target with more of a glancing blow ... again, check your attack map.

[Arclight]

:hmm:

Think he meant hitting the target at 10 to 15deg from a 90deg angle. At least that's what I made of it.

What you described is what I do nowadays; fire as the target is passing at bearing 0 / 90deg AOB, to make sure the torpedo hits at a more glancing angle. Works wonders for the mark 14 issues.

[Urge]

RR, it's time for you to come charging in and remind everyone of your discussion concerning this and Gutted's chart showing exact lead angles for a 90° hit and how just using generic 10°-20° lead angles results in a hit a little before or after 90°. Unless I'm missing something and there is a minimum degree over or under 90° that you need to attain to prevent the 90° firing pin issue. There are alternative methods of attack that preclude this possibility also since this problem seems to associated with an O'kane attack. I have never (as far as I know) had this issue. Duds and fish that run under their targets are common for me but not firing pin issues.

Urge

[Squid95]

I pretty much follow the excellent example in RR video tutorial "Dick O'kane" attack, which is an attack from 90 degrees of target course with a lead of 10 to 15 degrees. So I shoot BEFORE the target crosses 0 degrees relative this gives the warhead a slight angle on impact, duds are few.

I never switch on the PK and never look at the attack map, I shoot, lower scope and get the heck out of dodge, while listening for impact explosions of course.

I never worry about my solution. Its always right on. The only variable and the biggest problem is if the target maneuvers once it sees your fish. But if you loosed a nice salvo your spread will probably make up for that anyway. Another great aspect with this method is that you can put fish on target where you want them. Take most IJN cruisers for example, if you hit them just aft of the deck gun(just forward of the bridge) she will light up like a Roman candle, I think this is where powder bags were stored probably.

[Arclight]

Well, the point was really what would happen if you tried those attacks with RFB. I tried those attacks with stock, and you're right; they work like a charm. With RFB however, I can guarantee, from my own experience, at least a 75% dud rate. Fire 4 fish and expect 3 to go dud, sometimes all 4.

To avoid the issue, I'd advise a 75deg angle. Usually a good way to accomplish this is firing as the target is at bearing 0 / 180 (assuming you steered the sub on a 90deg angle to target course). Take you're final readings at that point and fire.

[Mush Martin]

I rarely if ever shoot 90 AOB at impact.
in RL it was discovered about the firing pin
as some or most of you know. According
to Lockwood the order went out almost
immediately to stop shooting perpendicular
shots.

further though a longtitudinal shot causes greater
damage in a magnetic shot.

I play RFB + RSRDC most days.
*note; when playing full up I enjoy relatively few duds.

M

[Squid95]

I am totally onboard with what you are saying.

Please let me clarify. I am currently running the lastest 1.5 with RFB and RSRDC, which I did not state before.

If you have seen RR's tutorial you would understand what I am saying and doing with the Dick O Kane method. Either that or I do not fully understand what you are trying to explain to me.

Here is my attack process:

Target: Course: North Speed: 12 Knots

I am approaching the target track from the east (relative to target) heading 270 at 2000 yards off the target Starboard Bow, I am at PD using my sonarmen to mark bearing of target.

Through the scope I line up my bearing to 350 degrees, on the TDC I enter the target speed, bring up range and minimize with the outer circle range setting and double click, this sets bearing to target in the TDC to 350 degrees.

I then bring up the AOB tool on the TDC. I set AOB to 80 degrees STBD and double click to input the data. This is due to the fact that when I fire at 350 ( the ship crosses my vertical line in the scope reticle ) the AOB to target will be 80 STBD.

This is because I know that my heading is exactly 90 degrees to target track. The zero bearing relative is 270 true nort. If I fired at 0 bearing relative I would set AOB to 90.

Firing at 0 would probably also result in an angled strike but I prefer to lead the target minimizing gyro resolver error and still giving a slight angle on impact.

This angle may change due to the range and speed of target. You can use the data disaplyed by the TDC after you have entered your solution data to view this angle and adjust as needed. Set AOB, double click, adjust your scope bearing, go to the range tool and double click. If you change any data remember to update bearing by double clicking the range tool.

Using this method I have very few dud strikes, from hundreds of shots.

This is by no means my method. I simply watched and learned. It has enabled me to truly immerse myself in the game at 100% realsim and still get some good tonnage.

[Arclight]

Seems like text book O'Kane to me, I imagine everyone using the method executes it like that.

Thing is you're leading the target by 10deg; by the time the torpedoes reach the target it will be crossing at bearing 0 / 90 AOB, meaning the fish will strike the target at near 90deg (give or take a couple of degrees). That is exactly what is causing the issue. Yet you don't experience much duds, where I would be lucky to get a detonation, even at slightly more glancing angles. :hmm:

Maybe it's down to the combination of mods?

[NSM + PE + RFB + RSRD] @100% realism (http://i268.photobucket.com/albums/jj2/EZatHome/untitled-1.jpg)

[Rockin Robbins]

Hi there! Sure has been fun reading all this. I've been off learning RFB. One thing I noticed is that on the attack screen your estimated torpedo track line is missing. That's bad, because I always look at the angle it strikes the track. If it is close to 90º, I'll increase my lead angle to shoot 10º earlier. That way I hit the target from 10º forward of the beam instead of at right angles.

In my Dick O'Kane tutorial I calculated to hit the target on almost a perfect right angle, guaranteed dud heaven if you are in the middle of 1943 or before playing RFB. Instead of shooting at 350º I'd back up to 340º to have that 10º difference from a 90º hit.

Now, why wouldn't I go forward 10º and shoot at the zero bearing with an AoB of 90º? It has to do with the duration of the torpedo run. While the target is approaching, his speed subtracts from the time of torpedo run, giving him less time to maneuver. If you shoot from behind, his speed adds time to the torpedo run, making it easier for him to avoid.

Hate to sound like an encyclopedia, but I have spent an altogether unhealthy time working all this stuff out with practice runs, stop watches and everything. Both ways work pretty well, but I'd rather shoot earlier than later.:arrgh!:

[Arclight]

Agreed, better sooner then later. ;)

Unfortunately, all this got me thinking. :lol:



If you don't fire your fish at 0deg gyro angle, you lose some accuracy with the O'Kane attack, correct?

Could this be corrected by taking a quick range reading just before firing?



This leads me to the first targeting method I developed before I "mastered" (cough) using the position keeper; I would observe the target over a lengthy period of time, allowing to draw / plot an accurate prediction of his course on the map. Based on that I would predict the targets position at a certain point, and use the map tools to gather the data. Drawback is that the sub has to be stationary for this to work.

1. speed; easy enough: mark, time 3 minutes, mark again and measure distance traveled, calculate speed.

2. AOB; mark a position along the predicted targets course, use protractor to measure bearing to that point. Say the predicted point is 15deg starboard, then AOB would be 75deg port (assuming you steered a perpendicular course to target's course).

3. bearing and range; using the measurement in step 2, you know the bearing is 15deg. Range can be measured by taking a ruler and measuring the distance from the sub to the "predicted position" mark. Point the scope at 15deg and use the dial to input the measured range.

Then wait for the target to pass in view and fire as the desired point is in the crosshair.



Basically all that is, is an O'Kane attack + a range reading. The range reading allows greater freedom when it comes to firing at a specific bearing and controlling at what angle the torpedo strikes the target, without sacrificing accuracy.

Also, for the bearing and range you can use the sonar. Point it at desired bearing, send bearing, take range with ping as target moves onto that bearing, send range and fire.

Another possibility is to activate the position keeper as the desired target point is in the crosshair. Now you're locked on to that specific point and you can delay firing as long as you want (given that data was accurate).



I think even just a quick ping for range when using the O'Kane attack can increase accuracy, especially when firing at anything but 0deg gyro angle.:hmm:

(sorry for the long version, like I said, I started thinking. :-? )