Calculating range and speed

[Frank0001]

Fellow kaleuns,

I've recently been struck with awe after missing a torpedo aimed at a single merchant going slow, at perfect weather and a perfect attack position.

It seemed I horribly miscalculated the speed of the bugger.
My question now is, what is your advice to gain the most accurate speed calculation?

Thank you in advance

[Laufen zum Ziel]

If you are playing GWX 2 thereis a built in nomograph (sp) where you pull it up
from the bottom of the map chart. You mark your first sighting on the map
with the marker tool then wait a while and then make a second mark where the target is now.
Then use your ruller and draw a line throug min-km-knts on the
graph that will give you speed.

The below link has a print out of the graph that you can alsso use. If your
not playing GWX there is a mod available. GWX also has a pull down speed chart from the map screen.


http://i262.photobucket.com/albums/ii113/laufen345/img002.jpg?t=1215914530

[GoldenRivet]

watch the target through the periscope while your speed is as close as possible to zero.

Id the target

point the periscope at a point slightly ahead of the target ship.

when the front of the target ship touches the vertical cross hair in the periscope start your clock and do not move the periscope.

when the back of the target ship crosses the vertical cross hair in the periscope stop your clock.

find the target ship's lenght in the recognition manual..

length of ship divided by time in seconds multiplied times 1.94 = speed in knots

round up to the nearest knot. for example if your calculation revealed a speed of 4.12 knots... call it 5 knots.

thats a quick "on the fly" method of calculating speed. and its pretty darned accurate.

for convoys, just "clock" the nearest ship, and its a safe bet that every ship in the convoy is moving at the same speed

[Frank0001]

Ooh thank you gentlemen, I haven't thought of those ways yet!
I was using the 'lock' function, and press the timer, but that seems to be fairly inaccurate at times.

I'll try your suggestions, thanks again!

[Badger Finn]

become competent with the OLC GUI and its 3 quick actions

speed distance AOB

once speed has been determined using the OLC GUI u can update (manually) the calcs for AOB and Distance in super quick time..sec's

its pin point acurate...

[UnderseaLcpl]

Iron sights and guesswork FTW.

[Frank0001]

Sorry, I might be incompetent, but what's OLC GUI?

[Puster Bill]

You might also build yourself one of Hitman's Kriegsmarine Whiz-Wheels, at least the backside of it that lets you do time/speed/distance calculations:

http://img185.imageshack.us/img185/5185/dsc00013ym5.jpg

It's pretty simple to make: Print it out on cardstock, cut it out, and pin the three "wheels" together in the center. Here is where you can get it:
http://www.subsim.com/radioroom/showthread.php?t=114351

This is a set of instructions by klh that shows you how to do many different calculations with this wheel:
http://www.subsim.com/radioroom/showthread.php?t=126824

Generally, I use the fixed wire method to determine speed if I don't already know it (ie., BdU tells me the convoy is moving at 7 knots). It's pretty accurate if you do it carefully.

With the fixed wire method, you have to be moving as slowly as possible. You set the vertical line right in front of the bow of a target ship. As soon as the bow hits the line, start the stop watch. Once the stern passes, you stop it. Since speed = distance/time, if you know the length of the ship you can calculate the speed. Also, it's AOB independent, except at very small/very large AOB angles.

[Sailor Steve]

Sorry, I might be incompetent, but what's OLC GUI?
OneLifeCrisis Graphic User Interface. Starting with JoeGrundman's U-Jagd Tools mod, OLC created a cool manual targetting tool that recreates the way it was done in real life. The original development thread:
http://www.subsim.com/radioroom/showthread.php?t=123323

The first GWX release:
http://www.subsim.com/radioroom/showthread.php?t=123955

The latest version:
http://www.subsim.com/radioroom/showthread.php?t=124639

And his combined mod with environmental effects:
http://www.subsim.com/radioroom/showthread.php?t=134186

[Frank0001]

That's some interesting information there, perhaps I'll print one out and make one myself!
I never knew there were so many ways to determine range and speed, besides the 'lock scope' function!

Thanks again for all the information

[joegrundman]

I can certainly recommend building a circular slide rule and attack course finder/attack disk- i have made 3 - however the U-jagd tools mod incorporates an in-game version for your enjoyment if you haven't the time or patience to make a physical model

http://www.subsim.com/radioroom/showthread.php?t=123373&highlight=u-jagd

[Puster Bill]

joegrundman is right, there is an in-game version of the wheel above (and the front side of it). There is also a stand-alone flash version that I use when it isn't convenient for me to use the physical version.

I do have to say, though, that I like using the physical version, and use it in preference to the virtual versions whenever possible. I also have a few slide rules that I've used. I still use a linear slide rule to do my AOB calculations if i'm using the "length/mast height" method. For some reason, linear rules are more intuitive for me when it comes to AOB.