Magic time for manual TDC in SH4?

[AngusJS]

In SH3, if you waited 3:15 to take the second target bearing, the length of a line drawn between the two positions equaled the target's speed.

What time should I use in SH4 (using the Imperial system)?

Thanks

[Bubblehead1980]

3 minutes.....target travels 900 yards in 3 minutes...your speed is 9 knots and so forth.

[Frederf]

In 1929 the International Extraordinary Hydrographic Conference established the nautical mile at 1,852m or roughly 2,025.4yd.

2025.4yd / 60 min = 100yd / X min

X = 2.9624 min = 2:58 to the nearest second.

Unless you use the 2000yd nautical mile in which case it's exactly 3 minutes. :woot:

[DigitalAura]

This is why its nice to have that nomograph thing in the TMO mod.... you can figure it out using any time and distance!:up:

[Rockin Robbins]

Yes indeed. However in the real war, all sub skippers just used the 2000 yards equals one nautical mile approximation with wild abandon and great success. After all, the error in the units is far less than any errors in measurements you will introduce.

Using conversions that are more precise than your ability to measure does not add to the accuracy of your targeting.

Accuracy is expressed in the concept of "significant digits." According to a scientist, the number 1.5 is not a precise number. Actually 1.5 is the set of all numbers between 1.4 and 1.6, but not including 1.4 or 1.6. 1.05 is the set of all numbers between 1.04 and 1.06, not including those two numbers. The number of digits used to express a number implies that your measurement is accurate enough to render those digits.

Now that you're totally bewildered, 2000 yards to the nautical mile is all you need for accurate targeting in the game or with a real submarine.

[Frederf]

Is it bad that I actually carried through the significant figures ("sig figs" as we call 'em) rules during my calculations? Unless you count the uncertainty in measuring distances using the ruler tool (which isn't involved in the theoretical magic time determination) 2.9624 minutes is 5 sig figs just like the (rounded) length of a nm. Can't unlearn the scientific habit. :timeout::wah::har:

Of course the error for using the 2000yd nm is tiny compared to the typical errors in the data. No one should feel bad or worry that they are missing out on any accuracy improvement worth mentioning. Even if the nomograph used the exact definition (which I doubt) it would only be off a pixel or two in certain cases more so than our typical level of precision using the mouse. However I'm pretty sure the nav map notes the difference as I've seen the 1000s of yards have a hiccup when switching to X.X nm consistent with the correct implementation.

I would correct the notion that "1.5 is potentially all values between 1.4 and 1.6." 1.5 would denote all values 1.45 up to but not including 1.55. There's no way to show the little bar over the 9, but I did just learn it's called a vinculum.

[DigitalAura]

@ Frederf.... :doh::dead::06: Where were you when I was going to school?

[Munchausen]

@ Frederf.... :doh::dead::06: Where were you when I was going to school?

:cool: He was probably shifting the Bell curve and raising the bar for the rest of us.