Dick O'Kane lead angle question

[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.

[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.