How to estimate speed?

[NiceSub]

Hello,
I watched so much tutorials etc..but i dont get how to calculate speed and how to use stopwatch.When i press it it says no enough data and yet u put AOB then via stedimeter get range and position keper is on and target is locked.What i am messing?Is there also some kind of formula??
Please if you write formula explain all math operation and also give some example with numbers and how to optainn that data used in formula.dont youst simply write me formula caouse english is not my mother language and i strugle then to undestand formula.
thnx in advance

[razark]

To use the stopwatch con to obtain speed, you need to do two bearing/ranges fixes with a period of time between them.

You can also mark the ship's position on the map. Wait three minutes, and mark the position again. The distance will give you the speed. If the ship traveled 700 yards, the speed is 7 knots. If it traveled 2000 yards, it traveled 20 knots. Every 100 yards traveled in three minutes is one knot of speed.

[I'm goin' down]

Razark's description of the 3 minutes rule is the easiest for computing speed.

Aternatively, divide the distance (in yards) by number of seconds and get the distance per second. Mulitply by 180 (i.e. 3 minutes expressed in seconds) to determine speed. The alternative is useful when you have not measured distance in terms of full minutes. Keep a calulator handy to save time calculating.

General rule: The longer the time used to meausre distnace, the more accurate the speed calculation. Note: firing at long range requires a speed be calcualted accurately to ensure the torpedoes hit the target, even under O'Kane.

[Pisces]

And if you know the length of the target you can time how long it takes to pass through a fixed periscope line. Fixed meaning it doesn't turn, and neither should your boat. If you point it at a bearing anything other than 0 or 180 degrees then your own speed will affect the result. So to avoid that you have to turn your bow or stern to just in front of the target and time the start and finnish of passing the line. Then divide length in yards by time in seconds. To convert that to knots double the result and add one tenth of it.

If you know length in meters then just double the value (not adding one tenth) to get knots.

[Soundman]

Welcome to the forums Nicesub ! First, just to be sure you know, use "X" on the keyboard to bring up the Chromometer (Stopwatch). Good advice has been given above. The most accurate will be by plotting on the map and marking the ship and measuring distance against the time. Here is a way to be very accurate....

If you have radar: When you first see (or are notified) a radar contact, go to the navmap and bring up the Chrono (X on keyboard).. Zoom in on the contact seen on the map. The contact will be updated with a new postion every 20 seconds or so, and when it's gets updated the contact will jump to a new position on the map. Get ready now! Hold your mouse over the button on the Chrono in anticipation, and as soon as you see the contact jump on the map again, immediately click the button on the chrono to start it. Quickly now, click on the black pencil (map tool in the lower left corner of the screen) and mark the position of the contact before it jumps again. Watch the chrono and mark the contact again at three minutes. At this point, it's a good idea to use the "ruler" (another map tool in the lower left corner) and draw a line from the first mark through the second mark and extend it a fair distance, as this will give you the course of the target. Now, measure the distance between the two marks (X's) on the navmap you made using the compass (also in the lower left on the screen). As stated above, 500yds=5knots, 1000yds=10 knots and so on....The longer time you have to measure the more accurate it will be. If you wait six minutes and measure the marks, divide by two to easily compute the speed. Example: if the distance is 1000 yds... 1000 divided by 2 = 500... 500 =5 knots...

Be aware, ships are not always traveling in whole numbers or even half numbers, but can be traveling in 10th's of a knot. It may depend on what mod you use. A couple years back or so, I debated this with a few people in a thread and the argument came about. I knew from experimenting, that a boats speed could vary in fine increments of speed. I was using the RSRDC Mod at the time and "Lurker" (creator of the mod) confirmed this... So, the bottom line is, if you want precision, especially for a long distance shot, you need to to nail down the speed as best you can.. It takes a little practice, but with a little patience, you'll be a good Skipper in no time at all. Good Luck! :up:

EDIT: BTW, out of curiousity I dug up one of the old threads (there were more than one) on this subject of fractions of knots and here it is: :D
http://www.subsim.com/radioroom/showthread.php?t=148069&highlight=fraction+of+knots

[Armistead]

You can use the pause button if needed and the tools still work to make markings, sometime this is helpfu calculating speed with the 3 min rule.

I have read lurker did use fractions, I'm sure with another tool as I don't think fractions are included in the ME, but I think lurker used python or notepad doing a lot of his work. The only issue is you can't use fractions setting speed, so not sure why it matters.

[Soundman]

You can use the pause button if needed and the tools still work to make markings, sometime this is helpfu calculating speed with the 3 min rule.

I have read lurker did use fractions, I'm sure with another tool as I don't think fractions are included in the ME, but I think lurker used python or notepad doing a lot of his work. The only issue is you can't use fractions setting speed, so not sure why it matters.

Must respectfully disagree about entering speed, you can enter fractions of knots. Although speeds are only shown in even numbers on the Position Keeper, adjustments in between the whole numbers do change the solution! Try this experiment to prove it.

Sit dead still in the water and set up tube 1 to fire a shot on an imaginary boat crossing left to right at 90 degrees traveling 10 knots. Try to set the shot to fire at 0 degrees gyro angle, straight out of tube 1 as you would with what Rockin Robbins calls the "Dick O'Kane Method" . Fire tube 1.... Now increase the speed to 10 1/2 knots, update the TDC and fire tube 2. Go to external view and you can observe that the tube 2 torpedo will run a course slightly right of tube 1 ! :up: This proves the theory that small adjustments in speed effect the shot and does indeed matter. :salute:

EDIT: I just reverified this and even a very small adjustment like a 1/5 or 1/6 knot in speed does indeed change the course of the torpedos. The longer you let them run, the more obvious the difference in course. Many will (and have) say this doesn't matter. I argue it does if you are shooting from a long distance or wish to shoot with precision to hit exactly where you aim. A 1/4 of a knot difference in a 2500 or 3000 yd shot may very well make the difference of a hit or miss, or hitting dead center vs bow or stern. I myself am a perfectionist and don't just want to hit the target, but hit the bullseye! ;)

[Armistead]

Don't have the game up, but I'll stand corrected. I guess I'm with those that don't see where it would have much use, hasn't effected my shooting. For sure you would have to have a precise speed measurment and I would think a few seconds off would effect a fraction of speed. I also play with cams and contacts off most the time, so I either get speed by the ship crossing the wire or stad measurements and I don't think you could determine speed fractions by either methods.

I do recall a few times playing RSRD that I'll get speeds like 9.5, but I almost always shoot by the wire, usually shooting spreads from in front of the bow back. I prefer M14's and most ships will speed up anyway, so I adjust tactics to deal with that.

It may be more useful with M18's. I sometimes adjust speed to do spreads and fractions may work better than knots.

[NiceSub]

Yeah that thing with marks works!!Last night i played midway batle and I saw the batleship called something with F..... i dont remember.He was more than 3000yards away i observed for minutes than i took ruler get how much distance he traveled and i calculated that he was going 13kt.than i put AOB int tdc an distnace too.and tubes from 1 to 6 fire!!!And result was that torps hit the target from bow to the midle of the ship!Pure distruction!!BTW batleship require 6torps????
BTW I amf flight simmer I fly 4 years on Microsoft flight sim and to this sub thing i am new just 3 days.

[NiceSub]

Can somebody give me insructions how to use hydrophone?How to know is he far or close?And things like that

[Armistead]

Go to the top search on the right and type "Hydrophones". You'll get about 1000 threads on the subject.

[razark]

Yeah that thing with marks works!!Last night i played midway batle and I saw the batleship called something with F..... i dont remember.He was more than 3000yards away i observed for minutes than i took ruler get how much distance he traveled and i calculated that he was going 13kt.than i put AOB int tdc an distnace too.and tubes from 1 to 6 fire!!!And result was that torps hit the target from bow to the midle of the ship!Pure distruction!!BTW batleship require 6torps????
BTW I amf flight simmer I fly 4 years on Microsoft flight sim and to this sub thing i am new just 3 days.
:yeah:

[Armistead]

Nicesub, sounds like you sent a Fuso to the deep 6.

Depends on mods, but 6 is about right playing TMO, although sometimes I've seen em sunk with 3 well aim shots at different turrents.

GJ:yeah:

[NiceSub]

Yeah it was Fuso..I just wanted to make sure that he will go down and wont return back or try to stay on surface

[Armistead]

You did right, sometimes when you have a capital ship, best to let it have it, never know about duds, how it will zig, so sounds like you shot a perfect spread....

Save some for the rest of us ...

[NiceSub]

I loked at the search for g
hydrophones but couldnt find anything good:So my question is:How do you know is he going fast and is he geting closer or further??

[Armistead]

There's a lot of work learning the sonar. I'll try to answer a few.

Obvious you can go to the sonar stations yourself. You can use the cursor or Home and End keys to move sonar. Over time you'll learn different ships have different sound. You can often hear them switching speed. You've probably figured DD's have a much faster prop whine.

As for distance, I can't remember stock, but you should have several icons for sonar, track nearest warship or merchant. As you track your sonar man will call out bearings, speed and tell you "fast approaching" and other general distances. These become more important when you play with cams and contacts off. I usually track nearest warship when I'm attacking. The problem is you can't trust this. A escort may be in your baffle, rear of your sub and won't be picked up on sonar, not to mention your sonarman often doe's a poor job tracking.

Obvious if you have cams on, you can see what's going on up there and how close ships are, without that cam...it's tough...you know escorts may be near, so do you come up and shoot or not.. One thing that is helpful with cams off is to turn up the sound so you can hear approaching ships. You can hear escorts coming in from about 1000 yards. What really helps is sitting in the con tower and looking up at the ceiling, sound is much clearer. Using your ears you can hear a DD coming and take evasive action.

The best way to get distance is to ping a target. Take command of sonar and focus in on a target. Once you have it, send a sonar ping. The ping travels through the water and will hit the target giving you a return ping. So you send a ping and wait for the sound of the return ping. Once you hear it, you send it to the TDC that second and it will give you range. The further the ship is away from you, the longer it will take for the return ping. Just know if the enemy has sonar they may hear your ping and come a looking. Very dangerous to ping warships and escorts.

Here is a link to a good guide for stock.
http://forums.ubi.com/eve/forums/a/tpc/f/6421019045/m/4351073726/p/1

[NiceSub]

Yeah I foung that likn very usefoul.I have some more questions and every day that I play silent hunter i raise more questions.So my next question would be:Can i customize realism in carrer mode??How to do it??

[I'm goin' down]

I suggest you raise new topics in a new thread. Notwithstanding that, when you elect a career, do the following:

In the captain's room at the beginning of the first mission of a career, click on the book on the shelf to your left. That will take you to the option menu screen, where you can customize the settings for the career. You must make the selection of the desired settings at the begining of the career, before you leave port. You cannot change the settings once the first mission of the career is underway, nor can you change settings when you retrun to port to refuel, etc. If you decide you must change the settings once you have left port on the first mission, you are required to start a new career. I hope this answers your question. Rule: Select the desired custom settings in port before you begin the first mission. The selected settings will apply for all missions undertaken in the career.

Hint: Many questions can be answered using the forum search function. There have been thousands of posts by other skippers, and this question, I am quite sure, has been addressed several times previously.

[yubba]

http://www.calculateme.com/Speed/FeetperSecond/ToKnots.htm ! 1 foot per sec = 0.59248 knots 1 Meter per Second = 1.9438444924406046 Knot

[Armistead]

I can change my realism settings in between patrols at home base any time in my career.....Do it all the time, some patrols I play with cams on, some off, but never had to start a new career.

[Pisces]

Must respectfully disagree about entering speed, you can enter fractions of knots. Although speeds are only shown in even numbers on the Position Keeper, adjustments in between the whole numbers do change the solution! Try this experiment to prove it.
...I agree, I am not sure if you need to use a point or a comma to enter the decimal mark in waypoint speed setting. But fractions certainly can, and do have effect in the game. Just make plots for over an hour or so an you'll see it moves the propper amount further than the truncated speed value.

[Pisces]

I loked at the search for g
hydrophones but couldnt find anything good:So my question is:How do you know is he going fast and is he geting closer or further??You may have overlooked this one. This method has been explained more than once in this SH4 section, or the SH3 section. It is sometimes also reffered to as the 3- or 4-bearing method. There are also some video tutorials about it. But this document is the clearest explanation that I can remember:

http://www.subsim.com/radioroom/showthread.php?t=160817

The hydrophone (passive 'sonar') only tells you the direction the sound comes from. You can listen to the noise and determine what sort of ship it is, if it is fast or slow, far or near, but you can't get a clear defined number of knots or nautical miles from it. His course direction is impossible to tell at an instant, as the crew seems to do. You'll have to deduce it from the change in bearing at fixed time steps, together with your own movements. It involves quite some drawing on the map or paper... and patience!, since bearings change quite slowly. The 'why' of it is quite mathematical, but this document is the best geometrical or graphical explanation of it.