Calculating target speed

jdkbph · 04-14-07, 02:43 PM

Forgive me if this is just a misunderstanding on my part... I just got the game and haven't progressed too deeply... but I'm confused by all the discussion about target speed calculation and stop watches and slide rules and all. Unless I've missed something critical in the various discussion threads (there are many and widely dispersed - hence the new topic) there's something very wrong here.

Assuming we're working with a fairly accurate representation of a WWII era USN TDC (eg, Mk4), why are we trying to calculate target speed at all? Target speed is a TDC ouput, not an input.

For instance, a typical approach phase observation might look like this:

Assumption: the classification phase is completed, with the target ID'ed, the initial range and relative bearing fed into the TDC, and an eyeball speed guesstimate used to start the plot.

Observation 1 - relative bearing, range, AoB.

several minutes pass...

Observation 2 - relative bearing, range, AoB.

I should note that periscope exposure on each of these observations was kept to a minimum... in practice less than 20 seconds per. Somewhat at odds with my understanding of the use and function of the SH4 chronometer...?

Anyway... this info is fed into the TDC and plotted on the manoeuvring board after each observation. Given the initial parameters, and the results of the two subsequent observations, target speed is now known (ie, calculated by the TDC) to a reasonable level of accuracy, and will be continually refined with each additional observation.

The only time Speed, as an observed data element, is ever actually used as a TDC input is during the classification phase.

Is this not the case with SH4? Having waited since 1985 (MPS' Silent Service, and everything in between) for a real WWII USN fleet boat sim, it would be quite disappointing to find that they haven't managed to get this right.

JD

Hitman · 04-14-07, 03:09 PM

Well to make a long story much shorter: The chronometer in SH4 *should* calculate speed, but it is broken currently in the game.

Quote:

Assuming we're working with a fairly accurate representation of a WWII era USN TDC (eg, Mk4), why are we trying to calculate target speed at all? Target speed is a TDC ouput, not an input.

That's partially correct. You could/should enter speed estimates in the TDC to start the position keeper function and by observing the difference between the predicted (By the PK) bearing of the target and the actual bearing of it, you could refine the solution. It's the tracking party who would calculate speed by measuring in the CIC with the "speed" ruler the distance between 2 observations at a given time.

Making it all short again: In SH4 playing with manual Torpedo shooting, you currently must calculate the speed on your own and input it in the TDC via the slide out tool on the upper right corner of the screen.

Hope that helps

KypFisto · 04-14-07, 03:29 PM

I hope they fix it eventually. I'm reading the 1.2 patch notes and it looks like its not going to be fixed in this particular patch...though I may be mistaken.

Joe S · 04-14-07, 04:30 PM

My understanding is that speed is something that must be entered into the TDC. The fire control party would use a manual plot and a manuvering board to come up with speed estimates which would then be entered into the TDC and adjusted as needed to get a good solution. The use of the topwatch is not very practical or realistic. I prefer to mark the locatioin of the target, wait one, two or three minutes or real time and mark the new location, measure the distance travelled and firgure out the speed accordingly. I have a chart prepared ahead of time that shows speed in terms of yards per minute, eg 11 knots = 330 meters per minute. I also have one for yards/minute but dont have it in front of me at this time. Unfortunatly, we dont have an accurate ruler in SHIV but with a little luck you can get a reasonably good speed estimate provided you are far enough from the target when you first see it to have time to do the calculation.

Target speed is the most important component of a good TDC solution. Range is the least important. As for AOB, if you are within 1,500 yards from the target's track, a reasonable estimate of AOB will be good enough. However, if you misjudge the speed by even a few knots, you will usually miss.

I prepared a chart way back in the SHI and sub battle simulator days, that geives the gyro angle lead based on the speed of the target. Range is immaterial. I dont know where it is right now but I doubt that I threw it away. at any rate, The best way to determine speed is to calculate it based on the manual plot. It would be great if the game would automatically note the time of the placement of a map mark. Joe S

jdkbph · 04-14-07, 04:44 PM

I wonder why didn't they include a manoeuvring board? I guess we're flying seat of the pants once again with respect to things like distance to track, etc.

JD

joea · 04-14-07, 06:26 PM

I don't get it, the chronometer in SH3 was unreliable and made you keep your scope up for a dangerously long time. Why are people clamoring for it?

04-14-07, 02:43 PM	#1
jdkbph Captain Join Date: Mar 2007 Posts: 508 Downloads: 104 Uploads: 0	Calculating target speed Forgive me if this is just a misunderstanding on my part... I just got the game and haven't progressed too deeply... but I'm confused by all the discussion about target speed calculation and stop watches and slide rules and all. Unless I've missed something critical in the various discussion threads (there are many and widely dispersed - hence the new topic) there's something very wrong here. Assuming we're working with a fairly accurate representation of a WWII era USN TDC (eg, Mk4), why are we trying to calculate target speed at all? Target speed is a TDC ouput, not an input. For instance, a typical approach phase observation might look like this: Assumption: the classification phase is completed, with the target ID'ed, the initial range and relative bearing fed into the TDC, and an eyeball speed guesstimate used to start the plot. Observation 1 - relative bearing, range, AoB. several minutes pass... Observation 2 - relative bearing, range, AoB. I should note that periscope exposure on each of these observations was kept to a minimum... in practice less than 20 seconds per. Somewhat at odds with my understanding of the use and function of the SH4 chronometer...? Anyway... this info is fed into the TDC and plotted on the manoeuvring board after each observation. Given the initial parameters, and the results of the two subsequent observations, target speed is now known (ie, calculated by the TDC) to a reasonable level of accuracy, and will be continually refined with each additional observation. The only time Speed, as an observed data element, is ever actually used as a TDC input is during the classification phase. Is this not the case with SH4? Having waited since 1985 (MPS' Silent Service, and everything in between) for a real WWII USN fleet boat sim, it would be quite disappointing to find that they haven't managed to get this right. JD

04-14-07, 03:29 PM	#3
KypFisto Swabbie Join Date: Apr 2007 Location: New Jersey Posts: 11 Downloads: 0 Uploads: 0	I hope they fix it eventually. I'm reading the 1.2 patch notes and it looks like its not going to be fixed in this particular patch...though I may be mistaken.

04-14-07, 04:30 PM	#4
Joe S XO Join Date: Jan 2002 Posts: 409 Downloads: 28 Uploads: 0	My understanding is that speed is something that must be entered into the TDC. The fire control party would use a manual plot and a manuvering board to come up with speed estimates which would then be entered into the TDC and adjusted as needed to get a good solution. The use of the topwatch is not very practical or realistic. I prefer to mark the locatioin of the target, wait one, two or three minutes or real time and mark the new location, measure the distance travelled and firgure out the speed accordingly. I have a chart prepared ahead of time that shows speed in terms of yards per minute, eg 11 knots = 330 meters per minute. I also have one for yards/minute but dont have it in front of me at this time. Unfortunatly, we dont have an accurate ruler in SHIV but with a little luck you can get a reasonably good speed estimate provided you are far enough from the target when you first see it to have time to do the calculation. Target speed is the most important component of a good TDC solution. Range is the least important. As for AOB, if you are within 1,500 yards from the target's track, a reasonable estimate of AOB will be good enough. However, if you misjudge the speed by even a few knots, you will usually miss. I prepared a chart way back in the SHI and sub battle simulator days, that geives the gyro angle lead based on the speed of the target. Range is immaterial. I dont know where it is right now but I doubt that I threw it away. at any rate, The best way to determine speed is to calculate it based on the manual plot. It would be great if the game would automatically note the time of the placement of a map mark. Joe S

04-14-07, 04:44 PM	#5
jdkbph Captain Join Date: Mar 2007 Posts: 508 Downloads: 104 Uploads: 0	I wonder why didn't they include a manoeuvring board? I guess we're flying seat of the pants once again with respect to things like distance to track, etc. JD

04-14-07, 06:26 PM	#6
joea Silent Hunter Join Date: Jul 2002 Location: At periscope depth in Lake Geneva Posts: 3,512 Downloads: 25 Uploads: 0	I don't get it, the chronometer in SH3 was unreliable and made you keep your scope up for a dangerously long time. Why are people clamoring for it?