Wolfpack

Wolfpack

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Optical Range Determination
Av Fox
This guide will teach you how to determine range with your onboard optics such as the periscopes.
   
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INTRODUCTION
This guide will teach you how you, with your periscope, can determine range with different levels of accurate results for different situations. It will show you how to use the distance table and overlay, it will show you how to calculate it with a formula and the logic behind it.

Why do I need to know the distance to something?
There are three main reasons why knowing the range to something can help you.
  • Avoid Detections
    Determine range to stay outside of the enemy's detection range.
  • Torpedo Solutions
    Determine range to know if you can reach the target and hit it accurately. It also is a requirement for accurate torpedo travel times.
  • Plotting Position
    If you know where you are, which bearing the target is and range to it, you can share their position over radio, you can maneuver around it to make time-efficient interceptions and through the range determine other usable data in a solution like their speed and course.
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FUNDAMENTALS
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The fundamentals of using optics for determining range, requires that you know how tall something is and at what angle it is in relation to the horizon from your perspective/position.

With trigonometry we can calculate range
R = H / Tan A
This relationship of the two sides H & R and Tan of A is true only if the angle between H & R is 90° (represented by the green right angle corner)

But how does it apply to us in reality? Well if we overlay the diagram over our submarine and the target, we can perhaps see it a bit better.
here we replace the variables R, H & A with:
A = ANGLE
R = RANGE
H = HEIGHT

RANGE = HEIGHT / Tan ANGLE

Normally when calculating with Tan, you have to use radians as your unit of angle and you can convert angles of degrees with this formula:
Radians = Degree° / (180°/π)

We will use these formulas later, but for now, lets change to something else.
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IDENTIFY TARGET & HEIGHT
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In order to know a ships height the U-boats were issued a book containing pre-recorded dimension data of active, known ship designs. This book is know as the "Ship Recognition Manual". So as long as you could recognize the ship you want to range to you could calculate the range to it.

So how do you recognize a ship?
This guide will not elaborate on that subject but there is another guide for that, available in the link below:
https://test-steamproxy.haloskins.io/sharedfiles/filedetails/?id=2871279241
Determine the height of a ships feature
Once you have identified the target you need to choose a feature on the ship that you can see with your periscope, this can be any feature but the taller it is, the better as it can cancel out human measuring errors later. When your choice have been made, you then can then measure the feature in the recognition manual to get its height from the waterline (See right image).

For the example (See image below) I personally chose the thicker pole in the front as its clear to see and about the same height as the rear mast and it is the tallest feature on this ship.


If the feature that you choose is the tallest mast on the ship, then you can read how tall it is in the stats in the upper left part of the recognition manual. But sometimes the recognition is not correct so it is good if you always consult it, however when you are close to a target, it wont matter much if a mast is 1-2m off you will get your range close enough. (See left image)


Using the funnel
Many times you can not see the tallest mast clearly and therefor you have to choose something else. The funnel of a ship is easily spotted at range and in poor weather so for ships you might encounter often like the 3 warships: Sloop(10m), Corvette(12m) & Destroyer(14m) you can use their respective funnel heights to measure the range with.
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MEASURE TARGET WITH OPTICS
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You should measure the tallest feature that you can visible see on the ship. This should be the same feature you measured in the recognition manual. The same way you measured from the waterline to the top of the feature you need to do the same with the periscope. Keep in mind that rough weather with high waves might obscure the ships true waterline and your result might be incorrect.

Bottom or top?
When measuring the target you can choose to measure from the bottom up or top down. Neither is better than the other but for some, one method works better for them than the other. Regardless, the results in the end will be the same.


Stabilization
With the waves rocking you around it can be hard to keep the periscope stable on your own so you can hold left mouse button [LMB] to stabilize. Your in-game character will then use their muscles and balance (as we do not have access to the sense of balance in the same way we would in real life) to steady the scope. But moving the periscope around too much will make your character loose control and you need to re-press and hold the [LMB]. In really rough weather, you could also try to submerge to suppress the waves effect on your submarine.

Red Crosshair Color
If you find it hard to see the black crosshair colors during night against a black nightssky, you can then change your periscope lines color and intensity. This is done by holding Left Ctrl [LCtrl] + using the mouse scroll wheel.


Brightness
If you struggle to see ships during night or day, you can change the brightness in the video settings or on your monitor or other external video programs. We players are always exposed to lights that normal U-boat crews were not and thus our eyes might not adapt to the darkness in the same way. Fun fact about eyepatches use in naval situations, were to let one eye adjust itself to the darkness while the other eye remains adjusted to light. U-boat crews had a similar system with red tinted goggles they wore before going on deck watch.
While Wolfpack is a game, players might not have the time to spend to sit an hour or so in a dark room to adjust their eyes befor they play a game, we need to cook, do homework, take care of our children etc. and we do all that in lit environments. So do not feel embarrassed if you have to change the brightness to even out the playingfield.

Vertical Scale
The vertical elevation scale is measured in 1/16° "Sixteenths of a degree". In many other U-boat games, they tend to use radians but historically the 1/16° unit was used. This is likely to do with the very small angles to work with. If this seams new to you, it was introduced in version 0.26 which means old formulas no longer work but this guide will show you the new formula.
Scale Increments
Every line is 10/16° and every 5th mark is 50/16°

For this example we can see that the front mast is 32/16°
because from the waterline it is 3 full lines and ~20% of the 4th line.
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RANGE WITH HEIGHT TABLE
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Vertical Distance Table
Sometimes it's not important with accuracy but just to get a rough idea of the range. Then one can use the Vertical Distance Table. The distance table is accessible by pressing [C] Then going to the tab "V Distance Table"

You use the vertical distance table by scrolling left/right to the colum that represent the feature of a ships height in the unit meters (m). Then you use the column of numbers below. There is two sub-colims.1 for ranges observed with "no zoom" 1.5x or while zoomed in "6.0x". Choose the sub-column that represents the level of zoom used when measuring.

Then you intersect the column with the Vertical View Angle/elevation the 1/16° value you measured.
Do note that there is only be increments of 10, so you might have to round to closest 10th.

The number that the row and column intersects on, is the range in the unit Hectometers (hm)
1 hm = 100 m = 0.1 km

In the example we been working on, we chose a mast with height 37m and we measured it to be at an angle of 32/16° while using the 6.0x magnification.
The results of this example is:
~45.2 hm = ~4520 m = ~4.52 km

Distance Table Overlay
You can also use the periscope distance table overlay to get the same result.
  1. You can enable it by pressing the [E] key
  2. You can set the height of the feature by either:
    1. Holding left Shift[LShift] + use our mouse scroll wheel
    2. Use the arrow keys on your keyboard
      • 🡐 -1m
      • 🡒 +1m
      • 🡓 -10m
      • 🡑 +10m
  3. You do NOT need to specify zoom as the game detects which zoom you are on
  4. Finally you have to check for which row that best corelate to the elevation angle we observed the feature.

Like the example above, we can see that in this case we get the same result:
~45.2 hm = ~4520 m = ~4.52 km


Alternative Method
So instead of rounding the results because you used the tallest feature and it wasn't exactly hitting a 10th increment on the periscope, you can choose a feature that happens to fit as close as exactly at any 10th increments.

In this example we can see that the roof of the superstructure pretty much matches 10/16° so lets use it. We need to measure it in the recognition manual as well and we can there see the roof is 13m tall.
The result of this method yields:
~47.7 hm = ~4770 m = ~4.77 km


Quick Ranging with Funnel
If you wanna range real quick, which can be suitable to do when attacking a convoy from inside so all ranges are really close and you have a limited amount of time because you would be loosing an opportunity to hit a target, you can use the merchants average funnel height which is 21 m for merchants of sizes Medium to Heavy ships. The number 21 wont work to good for light merchants and passenger liners (PL) but there is only 5 PL so its not too hard to tell the difference.

So when using either range table you can set the height for 21 m and then measure the funnel and get the range for it.
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RANGE WITH CALCULATION
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When calculating range we will use the formula above.

We need to convert the ANGLE to radians before we use it with Tan (unless you have a calculator that is set to work with degrees instead of radians.)
[Angle in 16th degrees°] / 16 = [Angle in degrees°] [Angle in degrees°] / (180°/π) = [Angle in Radians]
Lets put that into the formula above
RANGE = HEIGHT / Tan ( ([Angle in 16th degrees°] / 16) / (180°/π) )
The RANGE we get will be in unit (m) and will only work for un-zoomed (1.5x) periscope.
If we want to use the formula for zoomed (6.0x) periscope we can simply multiply it with 4.

So finally we have following formulas:
1.5x Zoom Formula
[RANGE 1.5x Zoom] = HEIGHT / Tan ( ([Angle in 16th degrees°] / 16) / (180°/π) )

And
6.0x Zoom Formula
[RANGE 6.0x Zoom] = 4 * HEIGHT / Tan ( ([Angle in 16th degrees°] / 16) / (180°/π) )

Simplified Formula
Most of the time you only need to use the formula for longer ranges where un-zoom 1.5x wont cut it and you don't want to work with a long formula like the one listed above. Then this simplified formula can work, it wont be as accurate but, it will be accurate enough that you wont notice the difference.

[RANGE 6.0x Zoom] = 3667 * HEIGHT / [Angle in 16th degrees°]

Example
With our example we have
Height
The height we get from the recognition manual
Angle
The angle we get from measuring the ship feature with the periscope.
Example: 37 m
Example: ~32/16° = ~2° = 0.034906585 Radians

If we put this into the 6.0x formulas we get this:
[RANGE 6.0x Zoom] = 4 * HEIGHT / Tan ( ([Angle in 16th degrees°] / 16) / (180°/π) ) 4 * 37m / Tan ( (32 / 16°) / (180°/π) ) = ~4238.2m

With the simplified formula
[RANGE 6.0x Zoom] = 3667 * HEIGHT / [Angle in 16th degrees°] 3667 * 37 / 32 = ~4240.0m

The difference is insignificant for use in a firesolution.
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CONCLUSION OF EXAMPLES
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If we compare our results we got through the example we used in this guide we can see that accuracy varies.

METHOD
RESULTS
Range with table (rounding angle to match):
~4520 m
Range with table (matching feature in full increment):
~4770 m
Range with formula (full formula):
~4238 m
Range with formula (simplified formula):
~4240 m

In the end neither method will be accurate if you are not properly measuring with the periscope which can be hard at times.
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OTHER METHODS
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There is a few other methods one can use to determine range using the optics but this guide will not go into depth with those methods.

  • Flag Rendering Range
    The flag of ships will render at 3000m when observing it with the periscopes, it will render in little sooner on the UZO due to that it is using 8.0x magnification.
  • Horizontal Distance Table
    The "H Distance Table" works the best at AOB 90°. At any other AOB the results will slowly distort. but it is possible to range with a ships length if you know its AOB and due to a ship is usually longer than its tall, it might get you a better result than vertical ranging.
  • 4-Bearings
    The in-game manual elaborates on this method further where you take 3 bearings from the same location, then move and take a 4th bearing from a different location. All bearings needs to be recorded at equal intervals between each other. The result of the procedure will provide you with a ships position on the map, its speed and course but is highly time-consuming.
  • Multi-boat Triangulation
    If you the bearing to the target from you and you know the bearing from another U-boat with their position then you can triangulate the targets position and measure the range to the position from you.
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AUTHORS WORDS
Using funnel for range
When I do inside attacks and I do not have time to range, I use the average funnel height of 21m. You are so close that even if you are a few meters off, you will still hit your target. If you miss It it wont be the ranges fault, AOB and speed effects the solution more.

New player mistakes
One of the major mistakes I see new players do, is that they do not range during transit. Players Even though you do not know at what range you will be detected, you are still not making any efforts to figure it out. If you know what range you get detected at then how can you know you are not at that range or getting close to it without ranging? Even after directly telling players they need to range and telling them at what ranges they get detected at, they do not heed my warnings and still get themselves detected. Save yourself some trouble and make sure you RANGE!
Who is responsible for the boat being detected? The Captain. But does it need to be the Captain that ranges? Yes unless the Captain delegates the task, but never delegate the task to someone that does not know how to preform the task. Train them, and supervise them until they preform the task at a reliable level. I like to delegate this task to the dive officer and I taks the player to use the OP when surfaced to "Warship watch", if the player don't know how, I teach them and when they know, I instruct them in when they should be informing me we are getting to close. Having another playing helping unlocks much of my attention as a Captain and it allows me to focus on other things. So no excuses now, if you can not do it yourself, then send them to this guide!

so Range, Range, Range, Range, Range!

Accuracy
Just because some methods don't offer high accuracy, it does not mean you should never use it. There is a time and a place for all of them. You just need to learn when, one is more relevant than the other.
6 kommentarer
Fox  [skapare] 20 okt, 2023 @ 12:59 
< blank > 25 aug, 2023 @ 9:28 
if you need a gide use foxes he dose the best gides
Fox  [skapare] 25 jun, 2023 @ 5:14 
New guide published

It aims to define Heading, Course, Magnetic/Relative Bearing and Angle on Bow
https://test-steamproxy.haloskins.io/sharedfiles/filedetails/?id=2994179687
BAmama665378 10 feb, 2023 @ 11:11 
Excellent, a material worthy of an award, I was able to learn a lot from this manual.
Fox  [skapare] 3 jan, 2023 @ 21:15 
Updated.

Featured guide from other author removed.
SUBSIM  [utvecklare] 6 dec, 2022 @ 20:12 
Very cool!, This is good stuff, Fox.