DarkSythe's ETE Equation

[darksythe]

Ok well its another boring night at work so i put it to good(i think) work to develop a Estimated Time Enroute Equation. Now someone will probably post and easier way to fiqure it out so all my work will have been in vain but it was still interesting to do.

Now i must state i am in no way a math whizz, so the format of the following may be in error. Please give feedback.

Also i must thank the Seawolves for the publication of the famed "6 Minute Rule" with out which this equation would not work.(Its in the blue book found on subguru if you dont got it get it!)

Speed = X
Miles = Y
Yards In 6 = D
Total Yards = A
Total Minutes = B
Total Hours = C

[(Y*200=D) (X*2025=A)] [(A/D=E)*6=B] B/60=C
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For those that find that equation difficult i will explain it now.

According to the Seawolves if you take your speed and multiply it by 2, then adding two zeros to the sum of that equation you will have the distance you travel in 6 minutes. Instead of doing it that way i have modified it to just multiply speed by 200 resulting in D.
20*200=4000<--D

Next we need to find out how many yards their are total in our journey for that we will take our total miles or X and multiply that by the number of yards in a Nautical Mile which is 2025 rounded off from 2025.37183, and this will give us our total yardage(Is that a word? lol) or A.
400*2025=810000<--A

Next we will take A(Total Yardage) and divide it by D(Yards In 6) multiply that by 6 and we will get how many minutes we will have in our trip total or B.
(810000/4000=202.5)*6=1215<--B

Then we will take B(Total Minutes) and divide it by 60 to get total hours(In decimal Format) to the end of our trip or C.
1215/60=20.25<--C

So to cover 400 miles at a speed of 20 Knots would take 20.25 hours or 20 Hours 15 Minutes.

You may ask your self who needs this formula?
Well the simple answer is skippers like me who like to make transits to and from there home port to their AOP(Area of Operation).

When done correctly this fomula works great. Now there is the possibility that i have overcomplicated this whole thing..... In that case you can just chalk it all up to the ramblings of an over worked night shift worker. :rotfl:

[LuftWolf]

yardage(Is that a word? lol)

Yep, that's a word. Common in American Football terminology.

Thanks for the mathology.

[darksythe]

Originally Posted by LuftWolf

Yep, that's a word. Common in American Football terminology.

Thanks for the mathology.

I guess so lol now i feel like a dolt.

[OneShot]

Nice Job

I'm not a MathWiz myself, but you can cut it down by one step ...

Y*200 = D (Yards in 6 Minutes)

X*2025 = A (Total Yards - for the distance)

A/D = E/10 = C (Total Hours of travel at constant speed)

Means instead of multiplay by 6 and then divide by 60, simply divide by 10 ... Of course you could take the easy way out and simply divide the number of seamiles by your estimated speed of advance (say 400nm / 20kts [1kts = 1.852nm / h) and you end up with a pretty close number to the one calculated with the other formula.

[Fandango]

Originally Posted by darksythe

So to cover 400 miles at a speed of 20 Knots would take 20.25 hours or 20 Hours 15 Minutes.

Actually, you need 20 hours to cover 400 miles at 20 knots and not 20.25.

The additional 0.25 is probably due to some rounding in the decimal figures...

[darksythe]

Originally Posted by Fandango

Actually, you need 20 hours to cover 400 miles at 20 knots and not 20.25.

The additional 0.25 is probably due to some rounding in the decimal figures...

Can you show the mathematics behind this? because i assure you that i have tested this formulas effectiveness quite thoughly. And also following the formula above there is no rounding of anything besides the number of yards in a nautical mile.
And that was down.

[Fandango]

Originally Posted by darksythe

Can you show the mathematics behind this? because i assure you that i have tested this formulas effectiveness quite thoughly. And also following the formula above there is no rounding of anything besides the number of yards in a nautical mile.
And that was down.

1 knot is one mile per hour
20 knots are 20 miles per hour

400miles : 20 knots = 20 hours

[darksythe]

Well as right and logical as that sounds the mathematics dont work out in a more complex equation to a simple number as 20 it works out to exactly 20.25.

Since there is no rounding involved in the equation it is pretty hard to simply discount the numbers.

Even if you were to not round the number of yards in a nm down you still would not come up with 20 hours transit time.

[Fandango]

Originally Posted by darksythe

a Nautical Mile which is 2025 rounded off from 2025.37183...

Here's the rounding. Use 2025.37183 instead of 2025 and you'll see that the hour time will be closer to 20 hours...

When I get home, I'll give you a FULL mathematical answer to the 20.25...

[zma]

(Sneaking in an explanation before Fandango gets home... )

The rounding is actually hidden inside the six minute rule. If you wanted to calculate in yards the exact distance travelled in six minutes, you'd have to multiply the speed in knots by 202.53718(...), not 200.

The six minute rule is just a very convinient approximation, which you can calculate in your head.

[Fandango]

Originally Posted by zma

The six minute rule is just a very convinient approximation, which you can calculate in your head.

A "rule of thumb"...

[Bellman]

knot (unit).
''In navigation, unit by which a ship's speed is measured, equivalent
to one nautical mile per hour (one knot equals about 1.15 miles per hour). ...''

[Bellman]

Appendix E Measurement Conversions. Tacman.

''1nm = 2025 yds = 1852 m =1.8 km. **However**
For simplicitys sake a nautical mile is often rounded to 2000 yds; this is the convention ' which was used in Sub Command.

Therefore 1nm = 2000 yds = 1829 m = 1.8 km. ( In SC .)

Range scale in DW is in nm and yards(where the scale is less than 1 nm.)

[darksythe]

oh well waste of time

[moose1am]

I enjoyed the reviews and learned a few things guys. Thanks for the discussion. Now if I can only remember the 6 min rule next time I get shot at. LOL

Statute Mile is not the same as a Nautical Mile is something that I know but often forget.

But hey I could not use this formula as I never go in a straight line anymore. And I am not about to try to integrate all the different vectors to figure out where I am.

What the game needs is a good GPS display on all the platforms.

Originally Posted by darksythe

oh well waste of time