Fast calculating speed,small tutorial with pix

[Dimitrius07]

Hi everybody ;)

I want to represent to you my way how i got speed of the target - with out waste to much time - time in thise game is almost always against you :D

Ok here we go - :arrgh!:

First we need to indification the target we want to destroy :rock:
http://img113.imageshack.us/img113/9906/sh3img512007057ms6.jpg


As you notice in the picture we have are first info - little Tram Steamer

Now lets get a second info - time.
http://img490.imageshack.us/img490/9671/sh3img5120070571vq9.jpg

note - don`t move your uzo or perescop - in thise time

http://img296.imageshack.us/img296/9186/sh3img512007058tr8.jpg

As you can see - we have now another info - time in sec (32 sec)

Now - lets do some Matematic :|\\

78.5 to divide 32 = aprox 2.453125
2.554545 its a meters per second - lets convert thise in knots
2.554545 To increase 1.946 = 4.7737 knots

Thise is our speed - since in the example the target is not in 90 degree - we can make it aprox 5 knots.
Note
Thise tutorial made when my uboat was on surface with speed 0 knots.

If you unable to unable to do the calculation in all stop - there is my personal tip
help me many times.

Lets say we move forward to the target submerge in constant speed of 2 knots.
Do the calculation exacly as i shown in the pictures. But when you get a final result simply you need To add 70% or 75% to the final result
for examp
you mofing forward to the target in 2 knots
you made a calculation and you get let say 5.45 knots
5.45 To add 1.5 = 6.95 or 7 knots the speed of the target

If you moving back from your target you need To take away 70% or 75%

for examp
you moving in back standart in 2 knots
your result is 9.76 knots
9.76 - 1.5 = 8.26 knots the speed of the target
----------------------------------------------------------------------------

I hope i actually help some one - with thise tutorial.

Good luck :yep: :up:

[CaptainNemo12]

Hi everybody ;)


Thise is our speed - since in the example the target is not in 90 degree - we can make it aprox 5 knots.



What do you mean not at 90 degrees? The ship looks like it's at perfectly 90 degrees from your point of view.... Or do you mean not at 90 degrees from the the 0 bearing on your UZO?

Anyways, great tutorial!!!

P.S.: Where did you get the 1.5 in your answer?

[CaptainNemo12]

Thise is our speed - since in the example the target is not in 90 degree - we can make it aprox 5 knots.



What do you mean not at 90 degrees? The ship looks like it's at perfectly 90 degrees from your point of view.... Or do you mean not at 90 degrees from the the 0 bearing on your UZO?

Anyways, great tutorial!!!:D

P.S.: Where did you get the 1.5 in your answer?

[RAM]

What do you mean not at 90 degrees? The ship looks like it's at perfectly 90 degrees from your point of view....


nope, the ship is not at 90º AOB. Just look at the ID book, the shape of the bridge. Then look at the ship's bridge in the pic. The ship has a noticeable deviation from 90 deg. It's hard to say from the pic, but I'd say that the AoB is less than 90 deg (the ship is coming nearer the Uboat as it advances). I'd give it a 75º AoB. Maybe Dmitrius can tell me how wrong I am in my estimation (I'm still trying to learn manual shooting)



Dmitrius, I feel like slamming my head against a wall for not thinking about this one before :damn: . It's so simple that it's beautiful!!!!. As I said before I'm trying to master the art of manual firing, and estimating speed in fast-shot setups has always been very complicated for me...however I don't understand those calculations very well. Let me see.

I measure the time the ship takes to travel it's own lenght on scope or Uzo. So far so good.
I get, say, 25 seconds for that same 78.5m ship.
78.5/25=3.14 meters/second.
I can do easily a translation of 3.14 m/s to KM/H (would be 3.14x3600/1000, result is around 11,3km/H), then translate the result to knots...(dividing by 1.8 would be enough for a rough number, result is around 6.1knots)

but...how do you change 3.14M/s directly to knots?...I'm a bit at loss here...




One further question, just in case you have the answer...for Uboat surface speeds what would be the correction factor?. Say, what about 4 knots?. And 6?.

I ask because I do a lot of attacks at 4 or higher knots if at periscope depth, just to be sure I am keeping the right depth during the attack...

[johan_d]

when its this close I just press fire..

[Dimitrius07]

RAM sorry but i don`t have a right answer to your question because i never do target solution in such high speed. And i also don`t recomed to you. The main reason is not only accurasity is also a mining to stay silent.
Moreover 2 knots will maintane the depth

[Dimitrius07]

Thise is our speed - since in the example the target is not in 90 degree - we can make it aprox 5 knots.



What do you mean not at 90 degrees? The ship looks like it's at perfectly 90 degrees from your point of view.... Or do you mean not at 90 degrees from the the 0 bearing on your UZO?

Anyways, great tutorial!!!:D

P.S.: Where did you get the 1.5 in your answer?

You will be surprised
Its not even 80 :D

To your second question
Its my personal discovering - and i wanted to share thise with others :p ;)

[wamphyri]

The one question that RAM had that I'd like to see answered is how you convert the meters/second to knots. That's the only part i'm also not 100% on.

[Dimitrius07]

I found the convert info on some Russian web saite, and as you can see its also correct ;)

[_Seth_]

The one question that RAM had that I'd like to see answered is how you convert the meters/second to knots. That's the only part i'm also not 100% on.
M/S x 1,946 = Knots

Trust me, Dimitrius07 has this exactly right(tested,tested and tested..).

IE: 14 meter pr second X (multiplied with) 1,946 = 27, 2 (knots).
Easy remembering: 1,946 = 1946 was the year after the end of WWII

[MONOLITH]

Good stuff.

The only part I didn't get, was the 70% add or minus for ownship speed.

He did 1.5 added to 5.45.

1.5 = 27.5% (of 5.45).

So he's actually adding 25 to 30% (which counters 70 to 75%) so is it just the way he phrased the sentence that's wrong?

[azn_132]

Thise is our speed - since in the example the target is not in 90 degree - we can make it aprox 5 knots.



What do you mean not at 90 degrees? The ship looks like it's at perfectly 90 degrees from your point of view.... Or do you mean not at 90 degrees from the the 0 bearing on your UZO?

Anyways, great tutorial!!!:D

P.S.: Where did you get the 1.5 in your answer?
U double posted.

[_Seth_]

:rotfl:Noone is gonna eat him for that...

[_Seth_]

Good stuff.

The only part I didn't get, was the 70% add or minus for ownship speed.

He did 1.5 added to 5.45.

1.5 = 27.5% (of 5.45).

So he's actually adding 25 to 30% (which counters 70 to 75%) so is it just the way he phrased the sentence that's wrong? Yes, it has to be. I get the same result as you. 5,45 X 27,5 divided with 100 = 1,498 ~ 1,5.

[Kumando]

The one question that RAM had that I'd like to see answered is how you convert the meters/second to knots. That's the only part i'm also not 100% on.
M/S x 1,946 = Knots

Trust me, Dimitrius07 has this exactly right(tested,tested and tested..).

IE: 14 meter pr second X (multiplied with) 1,946 = 27, 2 (knots).
Easy remembering: 1,946 = 1946 was the year after the end of WWII

Round to 1.95 its more easy ;) .

[RawRecruit]

Good stuff.

The only part I didn't get, was the 70% add or minus for ownship speed.

He did 1.5 added to 5.45.

1.5 = 27.5% (of 5.45).

So he's actually adding 25 to 30% (which counters 70 to 75%) so is it just the way he phrased the sentence that's wrong? Yes, it has to be. I get the same result as you. 5,45 X 27,5 divided with 100 = 1,498 ~ 1,5.

But he uses 1.5 in both the examples of moving towards and away from the target. The constant in both, though is the U-boat speed of 2 knots and 1.5 is 75% of 2, so I'd conclude that you add or subtract 70-75% of your own speed.

[RawRecruit]

I've been giving this some more thought and it's an intriguing method. However, I was thinking about if you were at a much smaller and more awkward AoB than the example, say at 30º. In this case the ship will take longer to cross the point of view and so the calculation isn't so straight forward. So I thought there must be some relationship between the time taken and the angle on bow. I came up with the following theory:-

- When timed at 90º AoB the ship will have moved it's entire length across the view finder in a set amount of time.
- When timed at any other angle, the ship will be perceived to move less distance across the view finder over a longer time.
- The perceived length (PL) of the ship is in direct relation to the AoB. The perceived length is sin(AoB) * actual length (AL). You can then divide this by the ships length to get the ratio of PL:AL, but seeing as sin(a) = opp/hyp, then simply taking the sin(AoB) gives the same result.
- If we multiply sin(AoB) by 100 we have the PL expressed as a percentage of the AL. So what, you ask? Well, the prefect time recorded at 90º should be the same percentage of the actual recorded time at your AoB. So, if you take the timing you recorded for the ship to traverse the centre line of the view finder and multiply it by the sin(AoB), you should get close to the amount of time it would have taken for the ship to cross at 90º AoB.

I could only test this with the figures given in the example above (I agreed with RAM that it looks about 75º, but the stopwatch looks more like 31.5 seconds to me). Eg:

A 78.5m tramp steamer traveling at 5 knots (2.56 m/s) will take 30.66 seconds to move it's own length.

If we take sin(75) * 31.5 = 30.42. Pretty close, huh? If we adjust slightly to 77º AoB we get 30.69.

I haven't been able to properly test this, and I'm sure that some proper mathematician will come along and tear it to pieces, or point out that it's already been proven before, but there you go. It was almost as much of an exercise for me to refresh a bit of trig.

There you have it...to my untrained brain, if you have an accurate AoB and you get a timing, you can quite quickly work out the speed of the ship, even from difficult angles.

[Sonoboy]

Why not use the simple and reliable of going to the hydrophone. Yes, I'm talkng about turns per knot. I forget the TPK value that ships have in this game, but it's somewhere here on this forum. I think it was around 24 TPK.

The method goes like this:

Count how many times the shaft of the ship turns per minute. The cargo ships have 4 blades, so you would be counting every 4th chug you hear. It will sound something like CHUG...chug...chug...chug...CHUG...chug...chug. . .

Divide the turns per minute by the TPK value, and you have the speed of the target.

Please note that you don't have to listen for a whole minute. You can do just fine by approximating.

[CaptainNemo12]

The one question that RAM had that I'd like to see answered is how you convert the meters/second to knots. That's the only part i'm also not 100% on.
M/S x 1,946 = Knots

Trust me, Dimitrius07 has this exactly right(tested,tested and tested..).

IE: 14 meter pr second X (multiplied with) 1,946 = 27, 2 (knots).
Easy remembering: 1,946 = 1946 was the year after the end of WWII

Multiply by 1.946? I thought Dimitrius said to ADD 1.946? I'm confused here....:-?

[Dimitrius07]

The one question that RAM had that I'd like to see answered is how you convert the meters/second to knots. That's the only part i'm also not 100% on.
M/S x 1,946 = Knots

Trust me, Dimitrius07 has this exactly right(tested,tested and tested..).

IE: 14 meter pr second X (multiplied with) 1,946 = 27, 2 (knots).
Easy remembering: 1,946 = 1946 was the year after the end of WWII

27 knots:o - what ship are you hunting mate - looks like a big British battleship :ping: :rock: i don`t know any merchant that has ability to travel that fast:D .

CaptainNemo12
You got thise right - just like _Seth_ sad
meters per second x 1.946 = knots
simple is that ;)

[_Seth_]

The one question that RAM had that I'd like to see answered is how you convert the meters/second to knots. That's the only part i'm also not 100% on.
M/S x 1,946 = Knots

Trust me, Dimitrius07 has this exactly right(tested,tested and tested..).

IE: 14 meter pr second X (multiplied with) 1,946 = 27, 2 (knots).
Easy remembering: 1,946 = 1946 was the year after the end of WWII
27 knots:o - what ship are you hunting mate - looks like a big British battleship :ping: :rock: i don`t know any merchant that has ability to travel that fast:D .

CaptainNemo12
You got thise right - just like _Seth_ sad
meters per second x 1.946 = knots
simple is that ;)
:rotfl::rotfl:Just an example people would remember, mate!

[mr chris]

U double posted.
Well at lest he does not spam:yep:

[Sonoboy]

I must appologize about my previous post. The method using turns per knot doesn't work for SH3, as the developers did not model it. :cry:

[hornetsting]

It works, thanks mate.

[VipertheSniper]

Just made a small excel sheet where you only have to type in shiplength and estimated AoB, and you get the time it would take the ship to cross your viewfinder with speeds ranging from 1-34 knots

I've protected all cells apart from the ones where you type in AoB and ship length, so the formulas are save from user error, but if someone wants to refine it, there's no password entered for the sheet protection.
Almost forgot to post the link

http://members.chello.at/reinhold.bisanz/speedcalc.xls

[hornetsting]

Link doesn`t work.

[danlisa]

Link doesn`t work.

Right-Click + Save as ;)

[joea]

Just made a small excel sheet where you only have to type in shiplength and estimated AoB, and you get the time it would take the ship to cross your viewfinder with speeds ranging from 1-34 knots

I've protected all cells apart from the ones where you type in AoB and ship length, so the formulas are save from user error, but if someone wants to refine it, there's no password entered for the sheet protection.
Almost forgot to post the link

http://members.chello.at/reinhold.bisanz/speedcalc.xls


Hmmmm thanks but trying to open it crashes my Excel. What version of excel are you using??

[VipertheSniper]

Actually I'm using Open Office, so I guess that may well be the problem. I'll reupload it without protected cells, when I get home, I don't know if that's what causing it crashing tho. Common sense would tell me it can't be the formulas, I mean even if they'd be wrong for Excel, it should be possible to open the file, but maybe display errors in the cells with formulas.

when I've uploaded the new file I'll edit the post with the link.

[dertien]

Why not use the simple and reliable of going to the hydrophone. Yes, I'm talkng about turns per knot. I forget the TPK value that ships have in this game, but it's somewhere here on this forum. I think it was around 24 TPK.

The method goes like this:

Count how many times the shaft of the ship turns per minute. The cargo ships have 4 blades, so you would be counting every 4th chug you hear. It will sound something like CHUG...chug...chug...chug...CHUG...chug...chug. . .

Divide the turns per minute by the TPK value, and you have the speed of the target.

Please note that you don't have to listen for a whole minute. You can do just fine by approximating.

This only works with the stock version of the game, the tables that have once been made to use this method won't work if you have different sound packs intstalled.

[don1reed]

Looks like you've had an epiphany, Dimitrius. Good find. I've seen that method used for many years, especially during foul weather when the target is bouncing around and you can't get decent range.

There is nothing new under the sun, however. If we'd search these forums we could dredge up tons of knowledged on "How-to". Its all there, if we'd only take the time. I've always had luck with: "...determine speed".

Cheers,

[VipertheSniper]

OK, took me a bit longer than I expected, but the file is now updated and should work with MS Office now too (Atleast I hope so)