Using a fictitious course to set TDC

[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 ...)

[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.


.

[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.


.

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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[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.