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-   -   John P. Cromwell attack technique on order (https://www.subsim.com/radioroom/showthread.php?t=143368)

Rockin Robbins 10-19-08 07:32 PM

John P. Cromwell attack technique on order
 
I was having an extended PM conversation with Nisgeis about targeting methods. He had a great idea about shooting from 45º ahead of the target to increase the speed of the torpedo relative to the target compared to the right angle approach of the Dick O'Kane method. His spider senses told him that the 45º attack might be as easy to deliver as a Dick O'Kane attack and come with a bunch of advantages. He could just about see how the thing would work, but couldn't quite put it all together. Does he ever have great instinct. His attack method is a gem!

In addition to the torpedo's speed, 70% of the target's velocity is helping bring them together more quickly!

Therefore for a shot taken at the same range the target gets much less time to react!

If for some unknown reason you blow the attack and the target is still 45º in front of you, you have time to set up another Dick O'Kane attack before he gets to you!

In a convoy situation an angled shot through the columns might miss your target, but has maximal chance of picking up another victim!

All that made me really curious. So I broke out MoBo--electronic maneuvering board and salad slicer. Shazzam! There appeared to be a way to make this work as easily as Dick O'Kane, with no outside tools or calculator necessary. Nisgeis wanted to call it Fast-45, but I hit him with aaronblood's true (damn! his arguments are ALWAYS true:nope:) contention that Fast-90 was a technique that required the U-Boat's periscope/TDC direct connection and calling this Fast-45 would just muddy the water.

The Dick O'Kane technique is named after a great submarine ace, who used similar but not exact TDC wizardry to bring down his targets. Why not continue to name these after great American sub commanders? Our list came down to two commanders, but one, John P. Cromwell, merited the name for several reasons. First, he never had the chance to use this technique. He died without notable success in destroying the enemy. But he received the Congressional Medal of Honor for a very special reason.
Quote:

Originally Posted by Wikipedia
While attacking a Japanese convoy on 19 November 1943, Sculpin was forced to the surface, fatally damaged in a gun battle and abandoned by her surviving crew members. Captain Cromwell, who knew secret details of the impending operation to capture the Gilbert Islands, deliberately remained on board as she sank.

And quoting his subsequent Congressional Medal of Honor citation:
Quote:

Determined to sacrifice himself rather than risk capture and subsequent danger of revealing plans under Japanese torture or use of drugs, he stoically remained aboard the mortally wounded vessel as she plunged to her death. Preserving the security of his mission at the cost of his own life, he had served his country as he had served the Navy, with deep integrity and an uncompromising devotion to duty.
So this attack technique will be a tribute to a true hero, who never got his chance to show his skill in a way that would make his name memorable today. But perhaps by naming an attack technique designed for a game, which itself memorializes the men who served, after this man, we might pause, while setting up this attack, to remember John P Cromwell, whose deed was every bit as heroic as those we celebrate: Mush Morton, Dick O'Kane, Sam Dealey or Eugene Fluckey. Let's remember Captain Cromwell as we set up this attack, named for him.

With the help of MoBo I've worked out the math and reduced its complexity so you can figure it out in your head in real time during the game. I've executed one practice attack, hitting four of four from 3300 yards. So it works.

Now the hard part: writing a set of instructions that YOU can use even better than I can, and making a tutorial movie for those who don't learn from written instructions. I can't make any promises on time. It's more important to do this right than do it on a schedule. I can tease you with my attack setup from the nav map on the prototype attack:
http://i196.photobucket.com/albums/a...154705_046.jpg

I could show you the picture of the tanker exploding, but that would just be bragging. I try not to do that, but to teach others to jockey their subs, hopefully better than I can. You can post your own explosions when this thing gets off the ground.:up:

Lexandro 10-19-08 07:39 PM

Nice post RR. As it transpires this kind of attack is how I have been approaching the game with Monsun/RSRD due to the large size of the convoys. By coming in at a 45 degree attack angle I can work a position to fire my bow and stern tubes in one flurry, using the targets forward speed as an "assist" to the torpedo travel time. That way I can hit 2 targets in one attack run and if I continue on my path I can work another shooting oppertunity from the convoy moving across my path.

While it would be much harder to do with full manual aim (ie work 2 sets of TDC calcs) the 45 degree attack angle method is a staple in my play book.

Rockin Robbins 10-19-08 07:52 PM

Lexandro, all my attack techniques are manual targeting techniques with the goal of making them so easy and enticing that you, on your next trip to port, will x that manual targeting option and go for it!

Even though it's cool to take out all the escorts and shoot multiple targets with auto-targeting, there is nothing to compare with all the whooping and hollering that takes place when you take out your first target on manual targeting.

My wife thought I was an idiot! Why does she have to be right all the time? It isn't fair....:oops:
http://i196.photobucket.com/albums/a...154334_546.jpg

SteamWake 10-19-08 08:04 PM

Quote:

Originally Posted by Lexandro
Nice post RR. As it transpires this kind of attack is how I have been approaching the game with Monsun/RSRD due to the large size of the convoys. By coming in at a 45 degree attack angle I can work a position to fire my bow and stern tubes in one flurry, using the targets forward speed as an "assist" to the torpedo travel time. That way I can hit 2 targets in one attack run and if I continue on my path I can work another shooting oppertunity from the convoy moving across my path.

While it would be much harder to do with full manual aim (ie work 2 sets of TDC calcs) the 45 degree attack angle method is a staple in my play book.

I too have been approachin at a similar angle... just made sence to me. As you said if you miss you still have an easy correction to fire again. Plus the closing angles of the torp and the intended target..... well just makes sense its faster.

Ive been doing this out of 'instinct' its pretty cool so see my guesses confirmed. :rock:

Lexandro 10-19-08 08:21 PM

Usually I try the full realism settings in a sim game and can get to grips with the after a bit of practice. In falcon 4.0 I have mastered the full realism settings of air-combat in an F-16 and I know exactly what every button and switch does and when and how to use it.

In SHIV however, its less instinctual than say flight is. Its more calculatory based combat, and to be frank I really cant get to grips with doing lots of math just to play the game. No doubt as some point I will get my head around it in a simple fashion, its just that for the time being manual aim is beyond my grasp.

If there was a proper tutorial mission just for working an easy shot, with lots of guide and tips on how to do so in the mission itself I might be able to learn it easier. Doing it hands on its a much more powerful learning tool for me than learning from study.

Rockin Robbins 10-19-08 08:26 PM

Nisgeis, why don't you pop in here and tell your story of how you thought up this attack method and what you told me that made me wrestle with all those nasty numbers?

XLjedi 10-20-08 08:50 AM

So, I see you're coming in on a 45° to the target TC.

Is that it? ...or is there something more to it? :hmm:

So far, I'm not really seeing any need to name it anything... :-?

Rockin Robbins 10-20-08 11:11 AM

Aaronblood, not to be sarcastic (on the other hand, why not?:arrgh!:), but there is one reason to name anything. Human beings have a weird psychological need to label things. Sometimes we even conclude that we know the name of something, so that means we understand it.

You're looking at a strange looking animal you've never seen before. "What in hades is that?" you say. "It's a flobberbitimous compressiceps" I say. You're perfectly happy, although you know nothing more about that strange looking animal than you did a minute ago.:rotfl:But you can tell your girlfriend you saw a flobbergitimous compressiceps and she will get that serious look that tells you she's impressed.

But more than anything names are handles for a collection of behavior directed at a desired goal. How do you find the location of a submarine by listening to it from two radio receivers? Triangulation. The word is shorthand for a complex procedure, usually performed by a team of different people.

In a similar manner, Dick O'Kane attack is a handle for a collection of actions including a course at right angles to the track, AoB being equal to 90º minus the number of degrees from the shoot bearing to zero bearing, turning the position keeper off, yada, yada, yada. I can say, do a Dick O'Kane attack here and you know the steps to take.

John P. Cromwell Attack will be the same kind of handle, encompassing a specific sequence of steps including a course at 45º from the track from ahead of the target, AoB being 45º minus the bearing, position keeper off, yada, yada, yada.

We name things because that is how our brains work. It helps us to remember. In these two cases they also help us to remember great submarine captains of World War II. Every time we pull off one of these tactics we remember them.

What could be bad about that?:up:

Nisgeis 10-20-08 02:06 PM

Quote:

Originally Posted by aaronblood
So, I see you're coming in on a 45° to the target TC.

Is that it? ...or is there something more to it? :hmm:

So far, I'm not really seeing any need to name it anything... :-?

I never really understood the Dick O'Kane method. I could never relate the instructions to the maths behind the technique. It just seemed a bit like a rough guess, which worked because you were very close to the target. I had a look on your tutorial thread, but that's a very brief snippet talking about a 7 knot target, with no details. Can you point me to the log behind it?

This new method came out of me trying to create a rule of thumb for a 45 degree attack, without using the TDC at all. I thought the Dick O'Kane method was a non TDC method to attack a target with a zero gyro angle, but it turns out the TDC is used and is more complicated that I thought.

My aim is to present a simple method people can use who want to do manual targetting, but don't want to use the TDC.

As it happens, I could not get an easy rule of thumb for 45 degree attack and after investigating, I found that the old speed plus three rule of thumb is also not satisfactory at all. I came up with a way to get the correct bearing of the target to fire at to hit with any torpedo track angle, with a zero gyro angle, by just using the map drawing tools. Just one protractor drawing and two rule drawings are enough to easily calculate the correct lead angle for a zero gyro angle shot at any intersecting courses for any given target speed or torpedo speed. It's essentially a constant bearing solution for torpedo and target, making the range irrelevant.

SteamWake 10-20-08 02:12 PM

But the bearing is not constant due to the targets speed and its AOB also any movement by your own boat.

Nisgeis 10-20-08 02:35 PM

Quote:

Originally Posted by SteamWake
But the bearing is not constant due to the targets speed and its AOB also any movement by your own boat.

Constant bearing, decreasing range is when two objects are on a collision course. The bearings of the two objects relative to each other stay constant and the range closes, until it reaches zero and you have a collision. The two objects will always collide, making range irrelevant.

Rockin Robbins 10-20-08 04:51 PM

There are three main methods of using the periscope to shoot torpedoes:

The check bearing method, where you take a series of quick observations to set up and confirm TDC inputs. Each periscope exposure is as short as possible . The periscope bearings are checked against the TDC to predict a good solution. We can do this and most do in Silent Hunter 4.

The continuous bearing method, where the periscope operator keeps the scope up and the assistant periscope operator calls out the bearings continuously to be entered into the TDC to keep it continuously updated during the firing of torpedoes. We can't really do this one. I suppose we could stab the send bearing/range button every several seconds, but that would reset the range to the last one we measured with the stadimeter.

Finally, the constant bearing method. Here the TDC is set for a predetermined solution. The periscope is aimed at the bearing determined by the solution and held on that constant bearing. As juicy parts of the target cross the wire you send fish their direction. All torpedoes follow the same path to the target in a longitudinal spread. The Dick O'Kane technique is a constant bearing technique, as is the John P Cromwell.

So with the constant bearing method the only thing constant is the bearing on which you hold the periscope.

It is true that from the point of view of the torpedo the target maintains a constant bearing until collision, but that is a factor shared by all three shooting methods and is irrelevent to the discussion.

Comprendé?

kiwi_2005 10-20-08 05:09 PM

Quote:

Originally Posted by Rockin Robbins
Aaronblood, not to be sarcastic (on the other hand, why not?:arrgh!:), but there is one reason to name anything. Human beings have a weird psychological need to label things. Sometimes we even conclude that we know the name of something, so that means we understand it.

You're looking at a strange looking animal you've never seen before. "What in hades is that?" you say. "It's a flobberbitimous compressiceps" I say. You're perfectly happy, although you know nothing more about that strange looking animal than you did a minute ago.:rotfl:But you can tell your girlfriend you saw a flobbergitimous compressiceps and she will get that serious look that tells you she's impressed.

:rotfl::rotfl: :up:

peabody 10-20-08 05:57 PM

Quote:

Originally Posted by RR
(refering to Nisgeis) Does he ever have great instinct.

Yes, he does!! I think I understand the consant bearing, decreasing range concept. I think I understand where you are headed, but don't have any idea yet how you are going to get there, eargerly awaiting that part. :hmm:

Just for discussion purposes , isn't a 45 degree shot going to cause problems with duds? In the torpedo .sim file the dud chance is 1% at 0 to 35 degrees, but from 35 degrees to 70 degrees it increases to 35%. (Unless I misunderstand the data.)

Peabody

Rockin Robbins 10-20-08 08:30 PM

Quote:

Originally Posted by peabody
Quote:

Originally Posted by RR
(refering to Nisgeis) Does he ever have great instinct.

Yes, he does!! I think I understand the consant bearing, decreasing range concept. I think I understand where you are headed, but don't have any idea yet how you are going to get there, eargerly awaiting that part. :hmm:

Just for discussion purposes , isn't a 45 degree shot going to cause problems with duds? In the torpedo .sim file the dud chance is 1% at 0 to 35 degrees, but from 35 degrees to 70 degrees it increases to 35%. (Unless I misunderstand the data.)

Peabody

:damn::damn::damn::damn:Well, I have good news and I have bad news. The good news is that the attack method works fabulously, both using the TDC and not using the TDC and I'll teach it both ways at once! The bad news is I'm about the worst movie maker in history and I screwed up four takes in a row tonight for technical reasons. I have put 16 of 16 torpedoes into various targets. This is just as deadly as Dick O'Kane and just as easy.

I spent a lot of time trying to talk Nisgeis out of drawing triangles on the nav map to aim the torpedo, tried it myself and I love it! It does require you to keep several pieces of information straight, but if your TDC ever breaks and you can keep your facts straight, you'll never miss the missing TDC.

Some might say that a 45º shot might not be as accurate as a 90º shot because of the lesser error tolerance and the smaller angular size of the target. Don't believe it. I hit 4 of 4 at 3000 yards with no problem.

But I don't have a good tutorial movie yet. Tomorrow will have to do. I think you'll enjoy it. It will be so simple that most of you will be better at it than I am in 24 hours. But I can't believe it. I filmed and talked myself silly for two hours and have nothing to show for it!:damn::damn::damn::rotfl:


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