A passive sonar only attack method?

[Rockin Robbins]

Hmmm....makes good sense. The prop count mod won't work at all because the prop is not continuously variable through the range of target speeds. There are only a few recordings of prop sounds and the game slides whatever one it wants to in there loosely based on target speed. So for a pretty wide range of speeds the prop count will be the same. The most you might determine is fast, medium or slow. That's not good enough. Hope they get that worked out in SH5.

But we didn't have any charts to relate rev count to target speed in WWII. The reason for that is that there was no database of Japanese shipping that was anywhere near comprehensive. It was a far cry from now, where the submarine has a database of just about anything bigger than a rowboat anywhere in the world and the sonar id's the target by name and gives pretty precise speed based on that id plus accurate rev/speed data for that individual target. We had data of questionable accuracy on a few warships and next to nothing on the merchies. So the knowledge just wasn't there to determine target speed by counting prop revolutions.

That's movie stuff. Let's not make the Das Boot error in the Pacific. As much as is possible, let's recreate reality, not movies.

Sonar WOULD have a valid function during the creation of the bearing rate table and chart, though. One of the assumptions, that the target maintains the same speed during the observation, can be verified by the sonar operator, and it is his job to announce any changes in target revs during the process. If he announces "target speeding up" you have to start the whole bearing rate analysis over again.

I guess you can guess that real submarines did this. And you know the game devs chose not to integrate bearing rate tables and charts into the game (add to the list of SH5 bells and whistles!). For details go to the Submarine Torpedo Fire Control Manual, page 5-43. It has the precise formula you need and it won't help!

Your way is MUCH quicker. Even better would be a reproduction of the authentic methods they used in the war. You don't read much about it because it wasn't done very much.

[XLjedi]

Originally Posted by Rockin Robbins

I need to look into this bearing rate formula a little more... If it can spit out speed/heading/distance based on variance in bearings, that might be a handy tool.

[Rockin Robbins]

I love it when they trot out the mind bender mondo-formula (this one really isn't complicated enough to qualify) and then begin the next sentence with "It is obvious..."

[Pisces]

Originally Posted by aaronblood

I need to look into this bearing rate formula a little more... If it can spit out speed/heading/distance based on variance in bearings, that might be a handy tool.

It may not contain exactly that formula, but this pdf should provide some insights and (modern naval) techniques to the things you want to workout.

http://files.filefront.com/NOE+Beari.../fileinfo.html

On page 4 of it are the formulas that my tool was based on. Pretty simple

[XLjedi]

Originally Posted by Pisces

It may not contain exactly that formula, but this pdf should provide some insights and (modern naval) techniques to the things you want to workout.

http://files.filefront.com/NOE+Beari.../fileinfo.html

On page 4 of it are the formulas that my tool was based on. Pretty simple

Actually, I've got all the math (thanks to Dr.Sid) for a least squares method of line fitting that will do everything... I've just been too busy (or lazy?) to incorporate it.

Take a look at this thread: TMA by Least Square Method

[Pisces]

Yeah, I know. I was just thinking about that. Creepy, huh?

[Rockin Robbins]

Now we're going well beyond techniques used in WWII submarines. I would prefer not to use anything that cannot be plausibly shown to have been in use then. Granted, given the knowledge they could have used the techniques, but I personally draw the line a little closer to actual practices.

Those are incredibly interesting though!

[Armistead]

I think I do better guessing..............

[XLjedi]

Originally Posted by Rockin Robbins

Now we're going well beyond techniques used in WWII submarines. I would prefer not to use anything that cannot be plausibly shown to have been in use then. Granted, given the knowledge they could have used the techniques, but I personally draw the line a little closer to actual practices.

Those are incredibly interesting though!

Yeah, but keep in mind, I'm workin on an app that isn't necessarily related to WWII tech anyway. Of course, you wouldn't have to use it, but it might be fun to make it work.

I wish I could just work on my apps full time, but I guess I gotta earn a living too...

[vanjast]

Originally Posted by Rockin Robbins

I would prefer not to use anything that cannot be plausibly shown to have been in use then.

With that in mind, my method of Course/AOB determination.

Visual AOB come with a bit of practise, and in the beginning one can guess within 20 Degs accuracy, this coming down to easily within 5 degrees with experience.

You want to put your sub at 90 Degrees to this course, so you must turn you sub on a course so that

Scope bearing = 90 - AOB (for Front tubes - STB side)
Scope bearing = 270 + AOB (for Front tubes - PORT side)

Scope bearing = 90 + AOB (for Rear tubes - STB side)
Scope bearing = 270 - AOB (for Rear tubes - STB side)

Now
Ship course = NEW Sub course + 90 (ship travelling from PORT to STB)
Ship course = NEW Sub course - 90 (ship travelling from STB to PORT)

To summarise:
With the sub travelling on any course:

For AOB < 90
Ship course = Sub course + Scope Bearing + (180 - AOB)

For AOB >= 90
Ship course = Sub course + Scope Bearing + (AOB - 180)

For answers > 359, just subtract 360 until your answer is <= 359

Just pulled this formula out of the hat - Preliminary checks look OK

[Pisces]

Originally Posted by Rockin Robbins

Now we're going well beyond techniques used in WWII submarines. I would prefer not to use anything that cannot be plausibly shown to have been in use then. Granted, given the knowledge they could have used the techniques, but I personally draw the line a little closer to actual practices.

Those are incredibly interesting though!

It's a valid point. I have no indications that it (my tool) was used during WW2 on either side of the globe. But I also do not feel the need to replicate exactly the procedures and practitions of those days. For me it is enough if the technique isn't beyond their technical means (like it being made as a slideruler instead of requiring digital computation, or requiring uber-fine bearing resolution).

Use whatever feels right in the end.