Calculating speed in metric ?

[Zyhgar]

Hi, I got silent hunter 4 as I am waiting for Uboats full release plus I am bored of playing as the germans.
But one thing I cannot figure out is how to get speed? The manual doesn't have ship length and I try the 3 min method and I still miss?
I have read several forums explaining the 3:25 method and tried it but I still fall short ? I'm doing the FOTRSU manual targeting 90 training mission get a distance travelled of 900m div by 195 seconds and get 5 knots (rounded up cause its like 4.8ect on the calculator) but I always fall short by like a good 50-100 meters. Help would be nice.

[Aktungbby]

Zyhgar!:Kaleun_Salute:

[propbeanie]

If the ship is traveling 900m in 3 minutes, then it is doing roughly nine knots. Looking in the mis file itself, the ship is set to do nine knots. :salute:

[KaleunMarco]

If the ship is traveling 900m in 3 minutes, then it is doing roughly nine knots. Looking in the mis file itself, the ship is set to do nine knots. :salute:
https://www.youtube.com/watch?v=Txa8XHq3N-8

[Zyhgar]

If the ship is traveling 900m in 3 minutes, then it is doing roughly nine knots. Looking in the mis file itself, the ship is set to do nine knots. :salute:

So am I doing the math wrong cause 900/195 keeps giving me 4.61+ ?

[razark]

Isn't it supposed to be 3:15 for metric?


(900 meters) / ((3 minutes) + (15 seconds)) = 8.97158997 knots




(100 meters) / ((3 minutes) + (15 seconds)) = 0.996843329 knots





A ship travels (approximately) 100 meters per knot in 3 minutes 15 seconds.
So, mark the position of the target, start the stopwatch. When it reaches 3:15, mark the position again. Measure the distance, divide by 100, and the answer is the speed in knots, reasonably close enough to get a hit. 900 meters, 9 knots. 850 meters, 850 knots. 2100 meters, 21 knots. You never need to divide by seconds or minutes.



For imperial, it's 100 yards per knot in 3 minutes.


(100 yards) / (3 minutes) = 0.987473002 knots

[ElCid97]

Easy way is 3 minutes and 15 seconds for metric to get the speed. Measure the distance between the two points and divide by 100 and you have the speed in kts. It's fairly accurate since it's based on the math for the whole 1,852 meters to a nautical mile (which is an exact measurement, by the way). Of course, the longer you take, the better the estimated speed.

Example: if you have 950 meters in 3:15, then your target is doing about 9.5 kts. If you keep the clock running to 6:30 (twice the time), your target should have covered 1900 meters if they kept a constant speed (950 x 2 = 1,800).

The second easiest (but not that accurate) is to use the nomograph if you have one. It's the ruler-looking-thingy on the navigation map which is included in most mods for both the US (nautical) and German (metric) sims.

Just place a line on the map. You then move one point to the minute(s) "mark" on the right-hand side of the scale, then drag the rest of it across to the other side and make sure the line is running OVER the distance covered in meters "mark" in the center. The speed (or close to it) should be on the far left side of the ruler-thingy under where the line is crossing the left-hand side of the scale.

In this case, you would put one point of the line on the right hand side over the "3" and then drag the rest of it over so that it crosses OVER the 900 meter mark. You'd then read the speed on the left scale.

That's good for an "on-the-fly" update as you're gathering your 3:15 or even longer (6:30, etc) to get a better idea of the target speed. Remember, patience is your friend. :D

If you did the 3 minutes flat and got 900 meters then you have to do the math since it's the time for imperial/US measurements in yards instead of meters. Well, it's technically 2:58, but 3 is good enough. :up:

To do the calculation it's this:

900 meters travelled in 3 minutes.

3 minutes = 60 minutes / 3 minutes = 20 (your multiplication factor since 3 minutes is 1/20th of an hour)

Then:

900 x 20 = 18,000 meters in 60 minutes (1 hour)

Then:

18,000 meters / 1,852 meters per nm = 9.72 kts (about).

So you're probably closer to 10 kts than you are 9 kts in this case, but if the target is close enough it isn't going to matter one way or the other -- especially if you're using electric. It just might make the difference between hitting just under the bridge instead of just under the funnel.

Now, if you're doing one of those 9,000 meter shots. Then, yes, you'd better use/calculate good data over a good amount of time. :D

Lastly, I'd suggest watching the early part of the career/campaign series by "Tonic87" over on the SH3 side. There are early episodes where he describes various approaches, methods, and targeting skills that are useful regardless of what type of boat your driving. I've used some of them in an S-boat while checking some of the things I'm working on, and it works. It shouldn't be any different with DW or OM, Type II, Type VII, or Type IX, etc.

There's one episode where he describes in detail a method that sounds like, "Ausgang for Barbie" where you get the data for the target based on how you maneuver your own boat. Granted, it helps to have the targeting disk to do that method he described, but if you're using the SH4 DW mod I believe it's in there already.

Hope this helped and I hope I didn't just make your head explode. I've been dealing with a lot of things here at home and needed some distraction before heading to work tomorrow, so I'm glad I saw this so I could put some of the things I've come across out there.

Regards,

ElCid97

PS: For the US fleet boats (and S-Boats), just use the 3 minutes and measure the distance on the map. As Razark said as I was typing, it's easier for the US side since you just "convert" the distance over by moving the decimal to the left two places. 900 meters should actually be 900 yards in this case if you're on a US boat, so 900 yds in 3 min = 9 kts

[Zyhgar]

Oh. Damn okay so I was just purely misunderstanding everything then which is a massive mistake on my part.
So I was looking at meters a second and not knots with my calculation so.
900/195 = 4.61 Meters/second then that goes into 8.96 knots rounded up is just 9 knots. AND I completely forgot that the answer was right in front of me the whole time 900m = 9knots 1100m = 11knots I completely forgot about that... I was just completely misunderstanding everything.
I'm so sorry for my stupidity I just was thinking in the wrong place. Thanks for the help.

[Zyhgar]

Isn't it supposed to be 3:15 for metric?


(900 meters) / ((3 minutes) + (15 seconds)) = 8.97158997 knots




(100 meters) / ((3 minutes) + (15 seconds)) = 0.996843329 knots





A ship travels (approximately) 100 meters per knot in 3 minutes 15 seconds.
So, mark the position of the target, start the stopwatch. When it reaches 3:15, mark the position again. Measure the distance, divide by 100, and the answer is the speed in knots, reasonably close enough to get a hit. 900 meters, 9 knots. 850 meters, 850 knots. 2100 meters, 21 knots. You never need to divide by seconds or minutes.



For imperial, it's 100 yards per knot in 3 minutes.


(100 yards) / (3 minutes) = 0.987473002 knots

I got the 3.25 from this old post when I googled.
https://www.subsim.com/radioroom/showthread.php?t=168130#:~:text=You%20can%20also%2 0calculate%20from,by%20100%20to%20get%20speed.

[razark]

Ah. 3.25 minutes.


Who writes decimal minutes? :06:

[propbeanie]

... Who writes decimal minutes? :06:
A mathematician looking to use his education in trigonometry... :arrgh!: