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, 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.

[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.

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

[Rockin Robbins]

CChhaaarge!!!!

[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]

Originally Posted by Arclight

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.

[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?).

Originally Posted by Squid95

...
Shoot everything 90 degrees to target track, ...

You should try that with RFB.

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

[Squid95]

Originally Posted by 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?).

You should try that with RFB.

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.

[Munchausen]

Originally Posted by Squid95

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.

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