[WIP]Preliminary Ship-vs-Speed formula

[vanjast]

For those that really enjoy a bit of Maths at 100% realism.

I've been doing a lot of time with regard to ship revs/speed timings and found that they all seem to follow a common formula.
I think this is what the Devs have used so they can use one-for-all ships.

This is a preliminary formula (calculated from 20 ships)which has worked for me so far. I still have to check all the ships, but you can use it as a 'guesstimate' until the real thing is ready.



One example.. I nearly missed here for lack of concentration, but hit anyway.
Ship discovered - start counting revs (count 20 revs) at this point.


Once we ID the ship, plug in Maximum speed into formula..


Start calculations....


I should have opened tube doors before firing, and incorrect speed (~0.5 knots too slow) was entered.. but it was good enough.


Quick surface to see end result


I'll carry on working on this so it'll be more effective at longer ranges.

[Xantrokoles]

I can't stand maths

But sounds like a great mod anyway

[vanjast]

It's not a MOD, but a simple formula/algorithm/method for using the hydrophone/sonar to calculate ship speed.

What it enables one to do is calculate target speed when the ship is on the horizon, so giving you more time to work on the other details of manual TDC.
I was working on a Rev/Speed chart but then noticed the same type of 'graph' with all ships, so whipped up the formula/method.

An exception is the one carrier which has it's speed settings messed up completely - this will require modding as the history 'engineering' books tell a different story to the game settings.

I used a speed chart method with SH3, and it never fails.

[Raptor1]

Does the number of screws on the target affect the speed calculations?

[vanjast]

I haven't taken note of this (will check though), but purely on hydrophone/sonar signatures the time range for 20 ships (thus far) has always been 19.5 - 44 seconds for 20 revs.
I'd imagine the game has not taken the prop blades or propellors into account when generating noise patterns related to shaft revs...

I like the idea of being able to calculate the speed from a rev count, but, math isn't exactly my stong suit.

Could anybody please explain this in a way that any math dummy, like myself, could understand it?

[Sailor Steve]

Good job vanjast!

Are you planning on making a series of charts for the "mathematically challenged", or is this just to give an idea of what's going on?

[Raptor1]

I think I understand the programming thingamajig (Correct me if i'm wrong):

If the target has no sonar signature it's speed is under 3 knots

if the target's screw makes 20 revolutions in under 20 seconds the target is within 3 knots of it's top speed

otherwise the target's speed is: (the time it takes for 20 revolutions -19) multiplied by (the ship's top speed - 6), divide that by 25 and...I didn't quite understand the last part

EDIT: I think I got it wrong :\

[vanjast]

Originally Posted by Raptor1

I think I understand the programming thingamajig (Correct me if i'm wrong):

If the target has no sonar signature it's speed is under 3 knots

Speed is 3 knots and under

Originally Posted by Raptor1

if the target's screw makes 20 revolutions in under 20 seconds the target is within 3 knots of it's top speed

Correct..

Originally Posted by Raptor1

otherwise the target's speed is: (the time it takes for 20 revolutions -19) multiplied by (the ship's top speed - 6), divide that by 25 and...I didn't quite understand the last part

Correct, and with that answer ..
You subtract 3 knots to get approximate speed.

There might be a problem with the boats with low 'top end', traveling at slow speeds.
I'll work this out.

Sorry for the elaborated formula text, I'm not sure how to write mathematical functions in MSWord so had to use this computer type algorithm method.

Sailor Steve:
I'm making individual charts that plug into the Recognition manual images. Started this a while back but RL has been preventing me from doing the 'more important things'.

This formula is a quick fix for speed calculations, as there are a gazillion ships to go through and with so many mods coming out I've put it off until now, as the game looks to have matured enough to continue, without the worry of ship data changing too much.

[vanjast]

This method now doesn't work with RFB1.5 for the following reasons:

The RFB mods replaces the original *_hyd.wav' files in the '\Sound\' folder with real recorded hyrdophone/sonar recordings.

The problem with these sound files is that they have shaft impulses in them, where as the stock sound files are 'flat'.

Now the game seems to superimpose another speed related function on top of the stock file so you get speed related rev impulses.
When the game superimposes this function on top of the RFB sound file, the result is a mess.

The next trick is to either re-install the stock files, or better, I'll edit the RFB files so that you get a 'flat' sound file. Another week-end gone

[vanjast]

Corrected this by 'shoving in' ROW sound mod over RFB, and we're back to normal.
This second torp hit a few feet further back from the first.


There's not much in the ..\data\sounds\ folder so just replacing the sound files is no problem.

NOTE: That Speed - 3 section at the end need to be 'fudged' a bit for the slower ships.
With this ship Speed + 3 worked.
It comes down to revs and visual indicators (like bow wave) - A bit messy but we'll get there sailors