EASY speed calulation

[mountainbikextremist]

My graphing calculator is smarter than your sliding rule!

Originally Posted by Rockin Robbins

Actually in WWII the plotting team had a collection of nifty analog slide rules that came up with the answer before you could go tap tap tap into your fancy plotting calculator. And their batteries never went dead!

Slide rules were cool before there WAS cool!

[vanjast]

Originally Posted by mountainbikextremist

My graphing calculator is smarter than your sliding rule!

I equal your Rule + Graphic Calc, I raise you 1x, my Wheely thing.

[denny927]

mmm sounds good this tutorial, but iam a noob for the yards and the mathematic in general lol ....anyone know the rules for calculating speed in meters using the same method for this tutorial???

thanks

[Rockin Robbins]

Sure, although imperial measurements make a lot more sense.

Take two positions 3 minutes 15 seconds apart. The number of hundred meters they are apart is the sub's speed in knots. 850 meters is 8.5 knots. Or you can take the number of meters in 30 seconds and multiply by .06 with mountainbike's snazzy calculator with the dead battery.

OH!!! Vanjast's wheely thing is K_Freddie's AOB Slide Rule, nothing but a circular slide rule. Actually it is three of them in one device! Let me see your graphing calculator do those same three functions at once and display them in separate windows like vanjast's wheely thing. Post pictures please. Methinks the old-fashioned slide rule wins a round here!

[Jaeger]

Originally Posted by mountainbikextremist

One of these days when I have some time, I am going to figure out how to get range w/o pinging as well. I just need to dedicate some time to sit down, do some searching for different techniques, and actually read them through them all the way.

there is a very nice way to get range by using the hydros only. no visual contact needed. if you are really interested, i can try to find the thread or describe it as good as i can...

[mountainbikextremist]

You have my attention sir!

Originally Posted by Jaeger

there is a very nice way to get range by using the hydros only. no visual contact needed. if you are really interested, i can try to find the thread or describe it as good as i can...

[mountainbikextremist]

I'll figure out the conversion when I get a few mins for ya. I assume you want to calculate speed off of 30 seconds?

Originally Posted by denny927

mmm sounds good this tutorial, but iam a noob for the yards and the mathematic in general lol ....anyone know the rules for calculating speed in meters using the same method for this tutorial???

thanks

[Pisces]

How about this:

Inside, Sh3 and Sh4 work in (kilo)meters. (afterall, the Ubisoft team was Romanian iirc) 1nm=1852m=1.852km, 1ft=0.3048m, 1yd=3ft=0.9144m, so 1nm=(1852/0.9144)yds= 2025(.4)yds

If a ship is moving 1 knot it is moving 1852 meters per hour, or 0.5144 meters per second. Let's say it is actually moving 10 knots, then it's moving 5.144 meters per second.

If a ship is moving 1 knot it is moving 2025 yds per hour, or 0.5626 yds per second. Let's say it is actually moving 10 knots, then it's moving 5.626 yds per second.

After 30 seconds a 1 knot ship has moved 16.9 yds (15.4 meters), and a 10 knot ship has moved 169 yds (154 meters).

But now my question, how accurate can you actually measure range? (and from that calculate speed)? Placing marks on the icons on the map is easy and deadly exact, but what steps does the line tool allow you to see? 50 Yards, or tenths of a nautical mile. And doesn't sonar give you noisy readings? Compare that to your average merchant ship movement at 10 knots in 30 seconds. Don't you think you should give it some more time to move it's butt and get it accurate? (if the ruler showed 100yds or 200 yds, what would your speed calculation say)

The true test of a technique isn't shown if you shoot a salvo of three torpedos at it. Can you consistantly hit it with just one torpedo? BTW, at what range was that?

To each his own play-style ofcourse. If you can't stand waiting a couple of minutes, then fine it is. But I seriously question it's efficiency. (with a Texas Instruments Sliderule or not! But I don't know what's so 'sliding' about this one though. )

[vanjast]

There is another simple way of determining speed..

If you adjust your speed so as to keep the target in one position in your scope (without target lock)

-If you have the ship at 30 degrees AOB and 60 degrees bearing angle, the target speed is 2x your sub speed.

-At 45 AOB and 45 Bearing target speed and sub speed are the same

-If at 60 AOB and 30 Bearing the target speed will be half your sub speed.

These are simple trig relationships that can work with the slower moving convoys. Only problem is that you'll make enough noise for the escorts, if you're going at speed.

[Fish40]

[quote]: But now my question, how accurate can you actually measure range? (and from that calculate speed)? Placing marks on the icons on the map is easy and deadly exact, but what steps does the line tool allow you to see? 50 Yards, or tenths of a nautical mile. And doesn't sonar give you noisy readings? Compare that to your average merchant ship movement at 10 knots in 30 seconds. Don't you think you should give it some more time to move it's butt and get it accurate? (if the ruler showed 100yds or 200 yds, what would your speed calculation say)



I'll say again that I have great success by timeing how long the target takes to cross the 0 bearing line of the scope, and useing it's length to determine speed. There are several lists out there that have the lengths of the in game ships, not to mention the fact that the poster of target ships that came with the box version of the game also lists the lengths. No fuss, no muss, no estimating. Works every time

[mountainbikextremist]

The map ruler goes in increments of 50 yards. 30 seconds is fast, but you will sacrifice accuracy as you noted. If you time for 3 minutes, you will get a more accurate speed then in 30 seconds. So far, I havent had any problems using a 30 second time span. I had 2 merchants traveling one after another. Fired off 3 torps at the first one, used the same speed I calculated for the second..adjusted my range, and AOB, and immediately fired off 3 more...all 6 hit home. If I run into accuracy problems at a longer range, I probbly will switch to the 3 min technique. And yes, pinging for range does make lots of noise...but you only need to worry about it if there are escorts about. Merchants seem to be pretty damn deaf, and only freak out if one of their fellow ships gets nailed, or if they see you on the surface. For escorted merchants, it seems to work pretty well to drop down past the thermal layer and keep your engines at going at 1/3. Once you are in range, kill your engines, and coast up to periscope depth. Nail as many ships as you can, and get back down as deep as you can before an escort starts crapping all over ya.

Originally Posted by Pisces

How about this:

Inside, Sh3 and Sh4 work in (kilo)meters. (afterall, the Ubisoft team was Romanian iirc) 1nm=1852m=1.852km, 1ft=0.3048m, 1yd=3ft=0.9144m, so 1nm=(1852/0.9144)yds= 2025(.4)yds

If a ship is moving 1 knot it is moving 1852 meters per hour, or 0.5144 meters per second. Let's say it is actually moving 10 knots, then it's moving 5.144 meters per second.

If a ship is moving 1 knot it is moving 2025 yds per hour, or 0.5626 yds per second. Let's say it is actually moving 10 knots, then it's moving 5.626 yds per second.

After 30 seconds a 1 knot ship has moved 16.9 yds (15.4 meters), and a 10 knot ship has moved 169 yds (154 meters).

But now my question, how accurate can you actually measure range? (and from that calculate speed)? Placing marks on the icons on the map is easy and deadly exact, but what steps does the line tool allow you to see? 50 Yards, or tenths of a nautical mile. And doesn't sonar give you noisy readings? Compare that to your average merchant ship movement at 10 knots in 30 seconds. Don't you think you should give it some more time to move it's butt and get it accurate? (if the ruler showed 100yds or 200 yds, what would your speed calculation say)

The true test of a technique isn't shown if you shoot a salvo of three torpedos at it. Can you consistantly hit it with just one torpedo? BTW, at what range was that?

To each his own play-style ofcourse. If you can't stand waiting a couple of minutes, then fine it is. But I seriously question it's efficiency. (with a Texas Instruments Sliderule or not! But I don't know what's so 'sliding' about this one though. )

[Torpex752]

In the Sub Force I used the following mental gym formulas that can easily be done in your head;

Speed X 100 = distance travelled in 3 min. or...

Distance travelled in 3 min divided by 100 = speed.

Frank

[denny927]

Originally Posted by mountainbikextremist

I'll figure out the conversion when I get a few mins for ya. I assume you want to calculate speed off of 30 seconds?

i posted an important question for all i can see
sure mountain. i want calculate speed each 30 sec.

ooooh now im not a bilge rat....

[Pisces]

Originally Posted by mountainbikextremist

... And yes, pinging for range does make lots of noise...but you only need to worry about it if there are escorts about. Merchants seem to be pretty damn deaf, and only freak out if one of their fellow ships gets nailed, or if they see you on the surface. For escorted merchants, it seems to work pretty well to drop down past the thermal layer and keep your engines at going at 1/3. Once you are in range, kill your engines, and coast up to periscope depth. Nail as many ships as you can, and get back down as deep as you can before an escort starts crapping all over ya.

By noise I didn't mean the 'audio' context. I meant that sending several pings results in different values, requiring to take the mean value. So 'noise' being more in the context of 'somewhat random'.

The method that Fish40 mentioned is an equally quick but more accurate means of measuring speed, when you make sure you cancel out the influence of your speed (by viewing along your direction of motion). Also, assuming the naval intelligence guys did their work on shiplength, ofcourse. It's accurate because you have a sharp steady line to measure with (acts like a virtual wall), and instead of counting short distances in steps of 50yds you count seconds with the chronometer. It usually does take around 30 seconds depending on the speed and length. And then a time that is 1 second off means speed will only be 3 percent off from the real value. But the use of some sort of calculator is needed to do the yds/sec to knots conversion. It's my favourite technique if I find a target that is not directly pointed towards or away from me, as some AOBs tend to hide the bow and stern behind the structures.

[Pisces]

Originally Posted by denny927

i posted an important question for all i can see
sure mountain. i want calculate speed each 30 sec.

ooooh now im not a bilge rat....

Why so often? Just once should suffice. It's not going to change unless the target reaches a waypoint or you are detected. The first doesn't happen very often, and the second you should avoid like the plague anyway.