Using a fictitious course to set TDC

[Rockin Robbins]

I promised when I lead another thread astray that I'd try to make a diagram or diagrams to explain my concept of shooting based on a made-up target course. The situation is that you don't know what the range of the target is so you make one up! Taking bearings three minutes apart, you plot those bearings on your fake target track to calculate (you guessed it!) a fake speed! This is sounding promising already.....

Now, I have finished my first chart and it takes the simplest case, where the course is actually at 90º to yours but you just make up a range for fun and profit. Works fine. Here's the construction:



So how do you like THEM apples? Make sense? Actually you don't even have to shoot this as a constant bearing attack. Turn on the PK, put in the range, AoB (90º at the last bearing point) and speed. Then shoot whenever you feel like it! Fill it full of holes if I'm wrong, I can take it! I don't think I have left myself any weasel room to deny it in that case. Let's reason this sucker out together and make it work.

[Urge]

I thought of this when I saw this post.

http://www.subsim.com/radioroom/show...0&postcount=47

Urge

[Rockin Robbins]

Yes, that animation started the whole revolution in fleet boat shooting here at Subsim. It was the result of U-Boat skippers gutted and aaronblood traveling to the dark side at the same time I was looking at the possibility of adapting U-Boat techniques to American submarines.

The more I look at my chart above the more unhappy I am with it. It looks too much like the Dick O'Kane chart and really should have two sightings, then the firing point at zero, then the torpedo track plotted for clarity. Don't have time to do it right now but I think the Mark II version of the chart should be done.

I also want to use it as a conventional targeting method with PK on so timing of the shot isn't critical. That would be fun too. Now that I can play SH4 again after I wiped and rebuilt my hard drives, this is a worthy first project.

Greyrider gets some credit on this one because a sonar technique will end up in the mix somewhere. Even though his 8010 idea never got anywhere he is still the first guy since I developed the Dick O'Kane sonar only method to attempt to develop a sonar attack method.

Anyone else who wants in, the water's warm! Contributions are welcome, including that of disproving the whole idea. Also if I have been unclear on any part of the concept I need to know. If the technique can't be taught it is useless. That means every step must be clear, easy to understand, easy to remember and easy to execute. There is no room for smoke and mirrors, unannounced tricks or unsupported claims in any legitimate tactic.

The fun is in covering every detail, making a set of instructions that anyone can follow successfully. The proof of success is when the student ends up shooting better than the teacher. The purpose of developing a technique is not so the originator can brag, but so that the students can brag about what great shots they are. That's the reward, right there! "I was frustrated and ready to quit playing but learning the xyz attack made me a successful skipper and saved SH4 for me" is the big payoff. I'll take a hundred times more criticism for the simplicity and lack of originality of the Dick O'Kane and John P Cromwell techniques in exchange for just one of those. Instead, I have received dozens just like it, and have repeatedly announced and shared the credit with all who contributed to the cause, especially to Neal Stevens who created the unique community in which this could take place. There are other sub simulation websites, but only one place where things like this happen.

[Pisces]

Thanks RR, for taking the effort of making it visual.

It certainly does look like the Dick O'kane method, but with one critical flaw. It relies on an assumed target speed. If the target speed is different than the real speed then you could miss ahead of the bow or behind the stern. It all depends on how much leeway the target's length gives you. I'm afraid this technique is in no way more guaranteed than Greyriders 8010 method.

[raymond6751]

It seems to me that you'd have to fire a spread to have a hope of hitting the target. I like it though.

[Rockin Robbins]

Originally Posted by Pisces

Thanks RR, for taking the effort of making it visual.

It certainly does look like the Dick O'kane method, but with one critical flaw. It relies on an assumed target speed. If the target speed is different than the real speed then you could miss ahead of the bow or behind the stern. It all depends on how much leeway the target's length gives you. I'm afraid this technique is in no way more guaranteed than Greyriders 8010 method.

Now be careful there! We're not just making up a speed. We're basing it on observation of two sonar vectors and projecting them on a fictitious target track. So long as the speed and track are proportional to the real one, you have created similar triangles and it will yield a valid solution.

Haven't you ever done the stadimeter thing and found through the attack map that your range is too short? As long as the impact x is on a straight line between your sub and the target, you have a hit, even though your range is wrong. You do have to reduce the speed proportionally to maintain the alignment if you're using the PK especially. That error was the inspiration for my idea. The only thing the solution has to yield is the correct gyro angle. If the correct angle is the product of an inaccurate speed and range the torpedo still makes a boom.

[Diopos]

RR
(and everybody else interested)
regarding the ficticious course attempt
up to now I have this: link

Hope it is "understandable"...

Fire Away!

(going deep now ...)

[Pisces]

Originally Posted by Rockin Robbins

Now be careful there! We're not just making up a speed. We're basing it on observation of two sonar vectors and projecting them on a fictitious target track. So long as the speed and track are proportional to the real one, you have created similar triangles and it will yield a valid solution.

Haven't you ever done the stadimeter thing and found through the attack map that your range is too short? As long as the impact x is on a straight line between your sub and the target, you have a hit, even though your range is wrong. You do have to reduce the speed proportionally to maintain the alignment if you're using the PK especially. That error was the inspiration for my idea. The only thing the solution has to yield is the correct gyro angle. If the correct angle is the product of an inaccurate speed and range the torpedo still makes a boom.

Ok my apologies, appearantly I still don't have my head screwed on correctly. I didn't realize the speed was derived from the bearing progression at this ficticious distance. You wrote it in the first paragraph, but I focused on the seemingly 'magic' 7 knots in the 2nd paragraph. Anyway yes, due to the proportional triangles the torpedo track would be the same.

Sigh, I need some R&R

p.s. no pun intended with that.

[Rockin Robbins]

Originally Posted by Diopos

RR
(and everybody else interested)
regarding the ficticious course attempt
up to now I have this: link

Hope it is "understandable"...

Fire Away!

(going deep now ...)

VERY interesting. Ideally I'd like to come up with a graphical solution so that external calculators aren't necessary. But I'm thinking that placement of the fictitious course influences the solution. Your diagram is better than mine. I need to get to work on something similar, showing two bearing sights, plus the firing position, plus the torpedo track.

Then the question: how does placement of the fictitious course influence solution quality? What kind of error tolerance do we have? I'm thinking at this point that we might have to use a visual AoB estimate to fix a non-right angle position of the fictitious course.

Good work! Now you've made me burn some midnight oil.

[Diopos]

For starters assume that you know target course.
Why? Because there is a bearings only method that allows you to do so. Implementable via passive means (sonar or optical observations no radar required). You won't like it though, as the sub must remain stationary as it collects data (at least three distinct bearing/time observation pairs). But if the target' is a medium or slow "mover" and you detect him early enough you may have time both for proper data collection and maneuvering.

{ I realy think you must go through this link: http://www.archive.org/details/maneuveringboard00unit }

Then you'll have to deal only with target's speed inaccuracies as range probably doesnt matter for small torpedo gyro angles.


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[Rockin Robbins]

Originally Posted by Diopos

For starters assume that you know target course.
Why? Because there is a bearings only method that allows you to do so. Implementable via passive means (sonar or optical observations no radar required). You won't like it though, as the sub must remain stationary as it collects data (at least three distinct bearing/time observation pairs). But if the target' is a medium or slow "mover" and you detect him early enough you may have time both for proper data collection and maneuvering.

{ I realy think you must go through this link: http://www.archive.org/details/maneuveringboard00unit }

Then you'll have to deal only with target's speed inaccuracies as range probably doesnt matter for small torpedo gyro angles.


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I've read through that and it's interesting. But I don't think it's usable for the average person playing SH4 and the techniques were definitely developed after WWII. And like you say, you have to stop the boat. I understand that in real life they have techniques where they don't have to stop the boat but our nav map doesn't have the tools to allow us to do the bearing rate chart. I just hate to break concentration by pausing the game and using outside tools. I know....it's a personal problem.

[Diopos]

Originally Posted by Rockin Robbins

I've read through that and it's interesting. But I don't think it's usable for the average person playing SH4 and the techniques were definitely developed after WWII. And like you say, you have to stop the boat. I understand that in real life they have techniques where they don't have to stop the boat but our nav map doesn't have the tools to allow us to do the bearing rate chart. I just hate to break concentration by pausing the game and using outside tools. I know....it's a personal problem.

It's the 1941 manual. It fought in WWII alright!

The "keep it in the game" principle is a very ... mature one indeed. But there can be "legitimate" exceptions such as using a Maneuver Board. After all you can plot in real time (not pausing the game). There are other kinds of solutions that are not as "knowledge intensive" as proper nav work. (And no I don't mean alt-tabing to an Excel spreadsheet). I'm in a brainstorm phase already!

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[Diopos]

RR,
any progress?



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[Rockin Robbins]

Originally Posted by Diopos

It's the 1941 manual. It fought in WWII alright!

The "keep it in the game" principle is a very ... mature one indeed. But there can be "legitimate" exceptions such as using a Maneuver Board. After all you can plot in real time (not pausing the game). There are other kinds of solutions that are not as "knowledge intensive" as proper nav work. (And no I don't mean alt-tabing to an Excel spreadsheet). I'm in a brainstorm phase already!

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Dont' misunderstand me. The in game only stuff is nothing but a personal choice. I'm not saying that using the maneuvering board, MoBo, Solution Solver, is/was, Capn Scurvy's tools or anything else are cheating. I just don't like leafing through pages of torpedo speeds, picking a row for target speed, a column for torpedo speed and plucking out a number because I'm dyslexic or something and keep making mistakes which are easily avoided by using what I do. In real life they really did all those things and had a whole bunch of other tools we don't, like bearing difference and bearing rate tables, stadimeter plots, tons of slide rules, etc. I'm just a guy who loves to boil everything down to the lowest common denominator, then explain it in english so clearly that my cat can outshoot me two out of three times.

You know, you're right about one thing. The maneuvering board is something very different from our nav plot. Real subs had both. I saved a copy of the manual as everything I have is from 1946, after the war ended.

It's not that I don't understand the higher math and I'm not afraid to share a room with a trig table. I'd just rather not if I can avoid it...

No progress yet. I've been wasting too much time on that other thread. Think my efforts would be better spent here.

[Diopos]

No problem!
BTW I truly meant "mature" (it was not ironic).
But have you done anything on "ficticious"?


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