Dick O'Kane lead angle question

[Rockin Robbins]

I received a PM from taukarrie that was so good the I think it needs its own thread:

your first O'Kane method tutrial that is. first off, very well done. a lot of my most recent ciritcal questions were answered by watching it just once. one question though...

when estimating your lead angle you, as a rule of thumb, go for 15 degrees. but you also said that it doesnt really matter what that number is. my question is why would you choose 15 degrees and why does that not matter?

it seems to me that the lead angle estimate is crucial for this method and to regard it so lightly confuses me.

thanks for your time.

OK, I'm going to do this without reference to my video, so I may be correcting my own error here. Here is where language becomes very important and I believe that it's important that we be careful to use the same terminology as the military.

Why? Because knowing that lives are at stake, they take great pains in using carefully defined terms that can't be mistaken for each other. They are extremely disciplined in their use of terminology. They don't tolerate sloppiness too well. In this case the sloppiness may be mine, so let me set things straight.

Taukarrie, I think the problem comes with the definition of "lead angle." The lead angle is the difference between the shoot bearing or aiming bearing, along which you sight your periscope at the target, and the bearing the torpedo travels to impact the target you're looking at. Of course, if the TDC just sent the torpedo up the aiming bearing, by the time the torpedo got there the target would be gone! But you've told the TDC that the target is on a course at right angles to your own, traveling at 8 knots. From that the TDC does its analog calculation mumbo-jumbo and says, well, I have to send the torpedo 10º (or whatever lead angle) ahead of the aiming bearing.

You see, Dick O'Kane came about because of my stupid mistake. I was using Gutted's great chart, which he had just adapted for fleet boats. It looks like this:


OK, so you pick the target speed out of the first column, travel across the row to the column reflecting the torpedo speed and there's your lead angle. We'll take a target traveling left to right at 8 knots. For a fast torpedo your lead angle is 9º. You subtract 9 from 360, where you want the boom to occur, and sight your periscope up the 351 bearing. So your lead angle is 9º and your aiming bearing is 351º. When the target crosses the wire, you push the button, the torpedo zips up the zero bearing and kaboom!

So I did it wrong when I first tried it. I looked across the 8 knot line and picked the wrong column. That gave me the 14½º lead angle for the slow torpedo. I aimed up the 345½º bearing and pushed the button. The torpedo shot up the zero bearing just as it was supposed to but there was no boom. The target got there after the torpedo did. I was a bit miffed.

Then I had an idea. If I could screw that up, so could everyone else. And that chart only had columns for fast and slow Mark 14s. How about Mark 18s and Cuties? Heck, that's two more columns to make twice as many mistakes! The chart is great but we are not. How can we fix that?

It just so happens we have a built-in chart on board that automatically knows what torpedo and what torpedo speed we have selected. It NEVER makes a mistake. It's called the TDC. When we're using the chart, we tell the TDC where we want the torpedo to go and WE pick the lead angle. Let's do it backwards!

Instead, let the stupid people pick the aiming bearing only! The TDC can calculate the lead angle for us and send the torpedo up any bearing it needs to to make a boom. In the Dick O'Kane bearing we pick an arbitrary aiming bearing with a goal of getting somewhere close to a boom at the zero bearing. That's where the rules of thumb come from: under 15 knots, pick 350 or 10 as the aiming bearing, knowing that the lead angle is going to be somewhere around 10º. If you have a faster target than that pick 20º and aim up the 340 or 20 bearings, depending on which direction the target is coming from.

Now this aiming bearing means nothing at all to the solution! Let me explain. Our target is coming left to right at 8 knots. I'm going to choose my 10º offset and aim up the 350º bearing. The TDC is set for 8 knots, AoB 90º-the 10º correction for an aiming bearing of 350º. But that 10º isn't the lead angle! It is the correction for the aiming bearing. We're letting the TDC set the lead angle. And if you check Gutted's chart you can see that the TDC does its magic and calculates the lead angle as 9º. So it adds 9º to the aiming bearing of 350º and sends the torpedo up the 359º bearing. BOOM!

So aiming bearing: where you point your scope. THAT's what we arbitrarily pick by rule of thumb in the Dick O'Kane method!
torpedo track bearing: the path of your torpedo. That is calculated by the TDC much more precisely that we can with a chart!
lead angle: the angle between those two bearings

Clear as mud?

[I'm goin' down]

I downloaded and ran the dick o'kane mission yesterday. I hit the tanker with all six shots. Shots nos. 5 and 6 were slow speed torpedoes. I assume the TDC automatically adjusts the lead angle when you switch from a fast torpedoes to a slow one? Or, when the speed of the torpedo is different do you have resend the range before firing?

Also, O'Kane, being a rule of thumb, becomes less accurate at long ranges. For example, you describe a scenario at 8 kts. where impact occurs at a bearing of 359 degrees. The lead angle is 9 degrees and firing point under O'Kane is when the target crosses the 350 degree bearing. Let's accept that it works at 1,000 yds. (practice verifies it does). It might not hit the target at 2,000 yds., since the firing point(a bearing of 350 degrees) is not when the target crosses a bearing of 351 degrees. The difference of one degree in the firing point (351 degrees [precise firing point] - 350 [Dick O'Kane firing point] = 1 degree.) when the range is 2,000 yds. rather than 1,000 yds. could result in the torpedo arriving at the impact point (359 degrees) before the target does. RR pointed this out in one his posts a long time ago, and, as I recall, the safest ranges for OKane are 800 (?) - 1,500 yds.

And, don't forget:

For the long distance shot, Rock n Shoals constant bearing method or gutted's chart diplayed above or gutted's Solution Solver program are good ways to go. The Solution Solver is pretty amazing.

And, for the angled shots, Cromwell or gutted Solution Solver program or manual targeting using the Easy Aob mod (PK activated) are tried and true techniques.

And my favorite: close your eyes, push all the buttons, and pray.

[Rockin Robbins]

Originally Posted by I'm goin' down

Also, O'Kane, being a rule of thumb, becomes less accurate at long ranges.....

You weren't paying attention. You are confusing a rule of thumb lead angle, which O'Kane does not do as explained above, with rule of thumb aiming bearing, which is the glory of Dick O'Kane. Yes, you pick the aiming bearing by rule of thumb. But the TDC calculates the lead angle with much greater accuracy than you could from a chart and with much more possible variability. It NEVER picks the wrong torpedo speed. It NEVER picks the wrong row unless you enter the wrong target speed.

Also, the lead angle changes depending on the aiming bearing. HUH??? Think about this. With an AoB of zero there is no lead angle at all no matter what the target speed. But lead angle is maximum when impact is at the zero bearing. Your charts can NEVER reflect the constantly changing lead angle with AoB. The TDC calculates it continuously and accurately.

Therefore if you decide not to wait and shoot when the target bears 340º, you can do that with Dick O'Kane and hit every time. With your charts you'll have to wait until he crosses the wire at 350º or just miss. What if you get distracted and don't shoot at 350? Using Dick O'Kane, you just aim up another bearing, like zero, press the send button and you'll still hit because the TDC adjusts for a new lead angle not found in ANY CHART! Dick O'Kane is MORE ACCURATE than a chart, not less because you are not using a chiseled in stone chart, you are using an analog computer which blows that chart all to Hades! It also eliminates a whole horde of human errors that come from using those charts.

So nothing that comes after your quoted statement has any validity whatever. The chart contains dozens of numbers. The TDC generates millions and millions. My money's on the TDC.

By the way, Fast-90, usable only by U-Boats, is even more flexible than Dick O'Kane because you don't need to do anything after TDC setup but point the periscope at the target, no matter what the bearing and shoot. You'll hit your mark, With Dick O'Kane in a fleet boat you have to press the send bearing/range button to send the new aiming bearing to the TDC. For maximum accuracy with Dick O'Kane you should also adjust the AoB, but the U-Boat's active periscope/TDC link automatically adjusts the AoB also!

[I'm goin' down]

Very interesting, Herr Doctor. So, why am I screwing around with other methods when the range is 9K or less. (9K seems too far, so let's settle on 4K.) Regardless of the position of the target vis a via my boat, O'Kane yields accurate lead angle that should produce an impact, assuming I have the course and speed of the target and set range to max distance. Admittedly, a broadside impact point yields the largest target profile, but the theory should apply to angled (i.e. smaller) profiles as well.

I may be experiencing a 2001 "dawn of man" moment.

[Rockin Robbins]

Exactly! O'Kane is the closest approximation we can get to the flexibility of the U-Boat attack at 90º to the target track. With it you can accurately shoot at any time before or after the only valid aiming bearing for a chart attack. This flexibility leads to more shots taken, therefore it leads to more hits per patrol. A shot not taken never hits its mark.

Remember that the Dick O'Kane instructional video is a BLOWN ATTACK. I was busily running my big mouth as the target blew past the aiming bearing. No matter! Without even updating the AoB (because there just wasn't any time) I just aimed up the zero bearing, pressed send range/bearing and shot anyway. Because the TDC automatically calculated the correct new lead angle, which was no longer 9º, I still sunk my target, salvaging both the attack and the video.

[Dignan]

Good stuff here. Thanks for the explanation/answer to taukarrie's question, RR.

I've got a follow on question of my own. I'm familiar with the Dick O'Kane method and have used it with great success. I recently read the tutorial for the "constant bearing" method. Basically, my question is "how is the constant bearing method different from the Dick O method?"

I will attempt to answer my own question to help myself understand the difference but if any of the experts could weigh in I would also appreciate that.

My perception is that CB differs from DO in the two following ways:

1. In constant bearing you are not limited to a 90 degree angle on the target track. You can attack from any angle.
2. In constant bearing method you must input a fairly accurate range to target track, unlike in DO method.

Are these the only two differences?

[Rockin Robbins]

Well actually "constant bearing" is not a single type of attack but a family of attack methods where you aim the periscope at a chosen aiming bearing and shoot as the target crosses the wire. It differs from other attack methods because they use the position keeper to continuously update target position. Therefore the TDC is continuously changing the bearing the torpedo will follow to the target.

In constant bearing techniques the bearing the torpedo will follow or the aiming bearing is held constant and you wait for the target to cross the aiming point.

Let's say we were shooting a shotgun. You can visualize that better. One way to shoot is to sweep the gun across the sky in front of the innocent cute duckie at the correct lead angle. You can shoot any time during the sweep and hit the target. That is conventional shooting.

But another way is to visualize the right lead angle, point the gun at a spot in a sky the duck must cross. You keep the gun stationary and time the shot for when the duck is at the correct lead angle. That's a constant bearing attack. All ducks are birds but all birds are not ducks. Dick O'Kane is just one kind of constant bearing attack.

Now with a constant bearing attack we have two choices. We can arbitrarily pick an aiming bearing and let our TDC choose the lead angle, as in the Dick O'Kane and John P Cromwell methods. Or we can arbitrarily choose our impact point and calculate backward to find our proper aiming bearing, using a chart, slide rule or computer, as in the vector analysis attack or gutted's 90º attack chart. Those two choices define the differences between varied methods of constant bearing attack.

If someone is taking a specific attack method and trying to name it "constant bearing" they need to change the name of the attack. "Constant bearing" already has a precise definition and has had it for over 70 years.

Dick O'Kane, John P Cromwell, vector analysis and Fast-90 are all constant bearing attacks. The first three can be used in any submarine, the last only with a U-Boat.

[taukarrie]

Making lots more sense now, thanks for the detailed explanation. I thought that with method you needed to pick an already calculated lead angle. I had the whole thing backwards.

Dignan mentioned that O'Kane is limited to 90 degree angles. I haven't seen it used at any other angle but I don't see why it couldn't work at any other angle. Especially since the TDC is doing the work

Rocks and shoals' tutorial for his constant bearing method is not quite the same as O'Kane. But it does seem a little more similar than that.

But, as always, im probably missing something.

[Dignan]

Originally Posted by Rockin Robbins

Well actually "constant bearing" is not a single type of attack but a family of attack methods where you aim the periscope at a chosen aiming bearing and shoot as the target crosses the wire. It differs from other attack methods because they use the position keeper to continuously update target position. Therefore the TDC is continuously changing the bearing the torpedo will follow to the target.

In constant bearing techniques the bearing the torpedo will follow or the aiming bearing is held constant and you wait for the target to cross the aiming point.

Let's say we were shooting a shotgun. You can visualize that better. One way to shoot is to sweep the gun across the sky in front of the innocent cute duckie at the correct lead angle. You can shoot any time during the sweep and hit the target. That is conventional shooting.

But another way is to visualize the right lead angle, point the gun at a spot in a sky the duck must cross. You keep the gun stationary and shoot when the duck is at the correct lead angle. That's a constant bearing attack. All ducks are birds but all birds are not ducks. Dick O'Kane is just one kind of constant bearing attack.

If someone is taking a specific attack method and trying to name it "constant bearing" they need to change the name of the attack. "Constant bearing" already has a precise definition and has had it for over 70 years.

Dick O'Kane, John P Cromwell, vector analysis and Fast-90 are all constant bearing attacks. The first three can be used in any submarine, the last only with a U-Boat.

Thanks for the detailed explanation. The tutorial I am referring to is here. http://www.subsim.com/radioroom/show...47&postcount=1

What makes this different from the Dick O'Kane attack? This tutorial implies that a 90 degree attack angle is not necessary. So my question is what makes this work?....is it the fact that you are entering an accurate range in the TDC where in O'Kane you don't have to???

[Rockin Robbins]

Yes, Rocks 'n Shoals method is different from Dick O'Kane because he is depending on entering the correct range. He is also running the attack with a stopped submarine, a big no-no on my list as a real submarine could not maintain depth control at full stop. I like to be as realistic in my behavior as possible. Yes, you're right that his entering an accurate range makes relative angles of target track and own course irrelevant.

But his is a constant bearing technique of setting the torpedo path and timing the shot for the target to cross the periscope sights. He does a very good job of explaining and illustrating his procedure step by step.

It shares the limitations of using the chart in that if you are forced to shoot at any bearing but the one you have chosen you are out of luck. Since constant bearing attacks are an ambush technique, that won't be a problem very much of the time.

[I'm goin' down]

Assuming, "this" refers to Robbins' explanations, the short answer is that it works because the TDC, being a machine, calculates the lead angle (9 degrees in his examples) even though the PK is not activated (i.e. the red light on the TDC is not turned on.)

Hypo 1:

A 450 foot wood duck, quacking wildly, is traveling from left to right at 8 kts, range 2,000 yds., bearing 270 degrees and closing. (It is lost and not flying very fast.) You put your shotgun away because it does not have enough fire power to bring down waterfowl of such immense size, and forget that it is Thanksgiving. You decide to take it out with a torpedo. You set the scope to 350 degrees, set Aob to to 80 degrees starboard (i.e. the duck is showing you its starboard feathers), and set range to 2,000 yards. Even though the PK is not activated, the TDC, which never sleeps, calculates a lead angle of 9 degrees. If you fire when the duck crosses the wire (i.e. at 350 degrees), the duck and torpedoes should rondeveous at 359 degrees.

Hypo 2:

Same duck as hypo 1, but you spilled your coffee and did not fire when it crossed the wire at 350 degrees. Swivel your periscope to a bearing of 10 degrees. Reset Aob to 100 degrees starboard, as the duck is flying away from you and still showing its starboard feathers. Click range. The TDC will recalcuate the lead angle to approximately 19 degrees (note, this should read, "approximately 9 degrees" and the term "19 degrees" is the result of a typographical error. See Robbins' comment in post no. 12, infra, where he caught the mistake.) Fire when the duck crosses the wire (i.e. 10 degrees) and the torpedo should hit the duck on its starboard side at a bearing of approximately 19 degrees [wood duck crosses wire and torpedo fired at a bearing of 10 degrees + 9 degree lead angle = torpedo and wood duck rondeveous at a bearing of approximately 19 degrees], as the TDC, even though the PK is not activated, calculated a lead angle of approximately 9 degrees.

The key is that the TDC will calculate the lead angle since it operates even if the PK is not activated.

[Rockin Robbins]

Aside from the 19º typo which you meant 9º lead angle with boom happening at bearing 19º, and the fact that both lead angles will be slightly different from 9º because they are not set for impact exactly at the zero bearing you have it exactly right! That is what make Dick O'Kane and John P Cromwell very resilient and resistant to human error. You can quickly retarget on the fly as coffee singes your gonads and you spend a bit of time cussing at the yeoman.

Perfectly explained!

[I'm goin' down]

I fixed the error noted in post 12, and referred the readers to that post as well.

[Dignan]

Originally Posted by I'm goin' down

Assuming, "this" refers to Robbins' explanations, the short answer is that it works because the TDC, being a machine, calculates the lead angle (9 degrees in his examples) even though the PK is not activated (i.e. the red light on the TDC is not turned on.)

Hypo 1:

A 450 foot wood duck, quacking wildly, is traveling from left to right at 8 kts, range 2,000 yds., bearing 270 degrees and closing. (It is lost and not flying very fast.) You put your shotgun away because it does not have enough fire power to bring down waterfowl of such immense size, and forget that it is Thanksgiving. You decide to take it out with a torpedo. You set the scope to 350 degrees, set Aob to to 80 degrees starboard (i.e. the duck is showing you its starboard feathers), and set range to 2,000 yards. Even though the PK is not activated, the TDC, which never sleeps, calculates a lead angle of 9 degrees. If you fire when the duck crosses the wire (i.e. at 350 degrees), the duck and torpedoes should rondeveous at 359 degrees.

Hypo 2:

Same duck as hypo 1, but you spilled your coffee and did not fire when it crossed the wire at 350 degrees. Swivel your periscope to a bearing of 10 degrees. Reset Aob to 100 degrees starboard, as the duck is flying away from you and still showing its starboard feathers. Click range. The TDC will recalcuate the lead angle to approximately 19 degrees (note, this should read, "approximately 9 degrees" and the term "19 degrees" is the result of a typographical error. See Robbins' comment in post no. 12, infra, where he caught the mistake.) Fire when the duck crosses the wire (i.e. 10 degrees) and the torpedo should hit the duck on its starboard side at a bearing of approximately 19 degrees [wood duck crosses wire and torpedo fired at a bearing of 10 degrees + 9 degree lead angle = torpedo and wood duck rondeveous at a bearing of approximately 19 degrees], as the TDC, even though the PK is not activated, calculated a lead angle of approximately 9 degrees.

The key is that the TDC will calculate the lead angle since it operates even if the PK is not activated.

Thanks for the explanation. Now I want to go play old school Nintendo Duck Hunter.

[General Tso]

An O'Kane method newbie here, so I'm probably going to make a fool of myself but what the heck I'm used to it.

First would I be correct in assuming that the definition of the O'Kane method is to aim each torpedo at it's own spot on the target rather than aiming at one spot and using offset angles to create a spread of torpedoes?

I looked at the different method's mentioned in this forum and found them to be somewhat complicated and confusing. So I tried doing it exactly as it's explained in O'Kane book and it seems to be a lot simpler and has worked for me every time. I've sunk about a dozen ships with it. Every torpedo hit. Most of the torpedoes hit very close to the aim spot. There where a few exceptions when the AOB wasn't close to 90.

First obtain the target's speed and AOB using your favorite methods and enter them in to the TDC. Then enter the distance and bearing and turn the PK on. The PK should now stay on the rest of the way. Update the range, bearing, etc. to "firm" up the contact as in closes.

When the time comes for firing make sure that the target is unlocked. Aim the periscope at the first aim spot and send the bearing only to the TDC and press fire. Repeat this for each torpedo.

I tried looking for a method like this in the forum but could not find it. If somebody has already posted it I Apologize for the repost.