View Full Version : EASY speed calulation
mountainbikextremist
03-01-09, 11:31 PM
1. Mark ship position on map, and start timing for 30 seconds.
2. Mark ship position on map after 30 seconds
3. Measure distance between two points in yards
4. Multiply that number by .06 to get your speed in Knots
Example:
Ship traveled 150 yards in 30 seconds
150 x .06= 9 Knots
Simple as that, and it is pretty damn accurate. I just sunk 2 large passenger ships using this technique "3 torps each" consecutively and all 6 fish hit home. Using this mod: http://www.subsim.com/radioroom/showthread.php?t=111371, I pinged both ships, and manually inputted their ranges into the TDC. I guesstimated their AOB and sent both to the bottom. That's pretty damn impressive for me since I have just started using manual targeting. I just have to keep a calculator by the computer:up:
Seems like a good tip:yep: Looks as though you don't need to identify the target useing this method. I haven't had any luck getting precise range measurements useing radar, since as far as I know, there is no numerical readout of range. There is a mod out there that addresses this, but I don't think it was made RFB compatable yet. IRL, there was indeed such a readout.
I've also used the sonar ping method, but also found that faulty on occasion. The way I do it is time how long the ship takes to cross the 0 bearing line of the scope, and calculate speed useing the ship's length. There are lists out there which provide the lengths of in game ships. Of course you need to ID the ship, a challange to say the least on a pitch dark night, but it works like a charm;)
Webster
03-02-09, 11:13 AM
further down the thread in post #12 you will see a different version of the same fix that works much better than how otto shows it.
mountainbikextremist
03-02-09, 12:26 PM
Do know what the name of the mod that corrects the range issue is?
Seems like a good tip:yep: Looks as though you don't need to identify the target useing this method. I haven't had any luck getting precise range measurements useing radar, since as far as I know, there is no numerical readout of range. There is a mod out there that addresses this, but I don't think it was made RFB compatable yet. IRL, there was indeed such a readout.
I've also used the sonar ping method, but also found that faulty on occasion. The way I do it is time how long the ship takes to cross the 0 bearing line of the scope, and calculate speed useing the ship's length. There are lists out there which provide the lengths of in game ships. Of course you need to ID the ship, a challange to say the least on a pitch dark night, but it works like a charm;)
Here's the thread, and included link: http://www.subsim.com/radioroom/showthread.php?t=142884&highlight=range+rings
Rockin Robbins
03-02-09, 09:04 PM
Why would you multiply by .06 and call that easy? Why not mark two positions three minutes apart and measure the number of hundred yards. 850 yards equals 8.5 knots. THAT's what's easy. Multiplying by .06 is not.
Armistead
03-02-09, 10:29 PM
I'm just trying to find the perfect way without contacts on to mark without pinging....Still time the passing of the ship through the crosshairs and checking my book....or leave it to the stad. Would rather have it down before they get that close.
mountainbikextremist
03-03-09, 12:21 AM
I am impatient and dont like having to wait 3 minutes to get my speed. 30 seconds is much faster:up:
Why would you multiply by .06 and call that easy? Why not mark two positions three minutes apart and measure the number of hundred yards. 850 yards equals 8.5 knots. THAT's what's easy. Multiplying by .06 is not.
mountainbikextremist
03-03-09, 12:26 AM
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. I would like to figure out the mast height to calculate range, and ship length for speed, as well as a good way to accurately calculate the AOB. One step at a time....I'm definitely making progress:cool:
I'm just trying to find the perfect way without contacts on to mark without pinging....Still time the passing of the ship through the crosshairs and checking my book....or leave it to the stad. Would rather have it down before they get that close.
It takes alittle practice, but with time you'll be able to ID targets in plenty of time. The first thing I look for is the position of the funnel. A funnel that is more or less in the center of the ship is a freighter. Tankers have their funnel aft. A sound check will tell you if you're dealing with a merchant or warship way before you see it.
Another thing I do is time the ship as soon as possible, even if I don't have the ID confirmed. Once you know the time, you could concentrate on what it is. Believe me, do it a few times and you'll see you have more than enough time to excecute an attack.
Webster
03-03-09, 11:53 AM
Why would you multiply by .06 and call that easy? Why not mark two positions three minutes apart and measure the number of hundred yards. 850 yards equals 8.5 knots. THAT's what's easy. Multiplying by .06 is not.
my dad always said those who take shortcuts work the hardest trying to work the least
but at the same time, different strokes for different folks, if its easier for him then go for it.
all i know is my brain hurts when i try to think so i do it as little as possible :D
Rockin Robbins
03-03-09, 06:16 PM
It would take me three minutes to multiply by .06!:nope::har:
mountainbikextremist
03-03-09, 09:39 PM
3 min even with the trusty calculator?:timeout::ping: TI83 Graphing Calculators are TOTALLY realistic...not that I need one to to multiply 150 by .06 though:know:
We need angle on bow sir!!!
Here hang on a min....tap tap tap tap, enter....its 32 degrees to starboard.
Whats her range?
Oh hmmm, sin multiplied by what number again?
Give me that, here just use the range function!
Oh its that easy? Cool...
Range: 60 yards...fire tube one!!!
Thats the way it worked in WWII right?:arrgh!:
It would take me three minutes to multiply by .06!:nope::har:
theluckyone17
03-03-09, 11:11 PM
Heh. In WW2, I'd probably be the guy sticking his wet pinky (finger) up in the air, checking for which way the wind's blowing. At 'scope depth, no less.
Rockin Robbins
03-04-09, 06:03 PM
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!:up:
Slide rules were cool before there WAS cool!
mountainbikextremist
03-04-09, 09:58 PM
My graphing calculator is smarter than your sliding rule!:smug:
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!:up:
Slide rules were cool before there WAS cool!
vanjast
03-05-09, 12:02 AM
My graphing calculator is smarter than your sliding rule!:smug:
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!:up:
Slide rules were cool before there WAS cool!
I equal your Rule + Graphic Calc, I raise you 1x, my Wheely thing. :D
denny927
03-05-09, 03:33 AM
mmm sounds good this tutorial, but iam a noob for the yards and the mathematic in general lol:88) ....anyone know the rules for calculating speed in meters using the same method for this tutorial???
thanks:salute:
Rockin Robbins
03-05-09, 06:09 AM
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.:D
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 (http://www.vanjast.com/SH4Mod/AOBWheelManual.zip) thing. Post pictures please. Methinks the old-fashioned slide rule wins a round here! :arrgh!:
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:rock:. 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
03-05-09, 11:43 AM
You have my attention sir!:salute:
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:rock:. 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
03-05-09, 11:46 AM
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?
mmm sounds good this tutorial, but iam a noob for the yards and the mathematic in general lol:88) ....anyone know the rules for calculating speed in meters using the same method for this tutorial???
thanks:salute:
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. (http://www.oddmix.com/spec/cal_ti-30.html) ;) )
vanjast
03-05-09, 03:48 PM
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.
[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
03-05-09, 05:41 PM
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.
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. (http://www.oddmix.com/spec/cal_ti-30.html) ;) )
Torpex752
03-05-09, 06:14 PM
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
03-05-09, 07:05 PM
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?
mmm sounds good this tutorial, but iam a noob for the yards and the mathematic in general lol:88) ....anyone know the rules for calculating speed in meters using the same method for this tutorial???
thanks:salute:
i posted an important question for all i can see
sure mountain. i want calculate speed each 30 sec.:yep:
ooooh now im not a bilge rat....:cool: :O:
... 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.
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?
mmm sounds good this tutorial, but iam a noob for the yards and the mathematic in general lol:88) ....anyone know the rules for calculating speed in meters using the same method for this tutorial???
thanks:salute:
i posted an important question for all i can see
sure mountain. i want calculate speed each 30 sec.:yep:
ooooh now im not a bilge rat....:cool: :O: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.
mountainbikextremist
03-05-09, 07:55 PM
These is the conversion I got....should be right:
Distance traveled in 30 sec (meters) x .02= speed in Knots
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?
mmm sounds good this tutorial, but iam a noob for the yards and the mathematic in general lol:88) ....anyone know the rules for calculating speed in meters using the same method for this tutorial???
thanks:salute: i posted an important question for all i can see
sure mountain. i want calculate speed each 30 sec.:yep:
ooooh now im not a bilge rat....:cool: :O:
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