The sound trainer by Greyrider and Captain Nautilus
 

Hardly any one ever mentions it in this forum, if at all (or I just can't seem to find references to it).

I think it's incredible that they've taken all that time and effort to collect all that hydrophone data to allow us to judge a ship's speed by just listening to their screws :|\

Does anybody else out there know about this??

P.S.: I allready have the info, but I forgot the link where I got it, so can anyone post the link to Greyrider's academy mission download so that other's can benefit as well?

Mmhh... :hmm: I think so that was not the method in that age.

You cant know the range to make the trigonometric functions needed to make that.

It is a modern method used in modern subs, where you determine the propeller turns and knowing the "fingerprint" for that ship, then you use the data about that ship to have "knots per turn".

With speed and time you can determine a distance.

Then knowing that distance, and angular variation between 3 points, you have an unique line, with an unique inclination, at unique range, and you have your firing solution.

You can do it manually if your computer is broken, or you can use the TMA (Target Motion Analysys) machine wich do theoreme solutions automatically.

But in WW2 age, the periscope was used to determine range.

I am not sure they can determine propeller turns/min in that age, plus they need the data about how many knots per turns is corresponding to that ship. I think so they had not that data in that age.

:up:

i hate to say this, but redwine has given you wrong information, this method was used by american submarines in ww II.
propeller pitch was known then as it is now. TMA is a more modern way now. but not then.
below is taken from fleet submarine.com, which is all about wwII
fleet submarines of the american fleet.

http://www.maritime.org/fleetsub/

How to take a turn count
1. Train the hydrophone directly on the bearing where the prop beats are loudest.

2. Turn the prop-count detector ON. It may bring out the beats more clearly. (If it does not, turn it OFF.)

3. Notice whether the beats are accented or unaccented. Accented beats go CHUG, chug, chug (three-bladed propeller)-or CHUG, chug, chug, chug (four-bladed propeller). Unaccented beats go chug, chug, chug, chug, chug.

4. Get in rhythm with the beats by pumping your arm up and down. If there is an accented beat, let your hand come down with every accented CHUG -or if the beats are all the same, on every chug.

5. Count the number of times you pump your hand down in 15 seconds.

6. Multiply this count by 4 to get the number of rpm (revolutions per minute). Report the rpm immediately. For example, if your 15-second count is 24, the rpm will be 96, and you will report: "JP, turn count is ze-ro nines six. Good count." If the beats are so rapid that you are not sure of the accuracy of your count, report: "Poor count."

7. After you have reported, make sure that the prop-count detector switch is OFF.

as you can see, it was used in ww II.

http://u-boot.realsimulation.com/

Dick O'Kane allso writes extencivly about how one of the torpedomen used a brush on a microphone to simulate intercepts on the long legs towords the patrol area. They had manuals to describe how the brush should be used and how many counts etc. to complete a simulation with maneuvres and all.

To much work and in convoys there is a one big chugga-chagga-chug, with DDs you can't count it at all. I rather rely on slow/med/fas and my more or less judgment of sound level. Hmmm to be honest, recently I do everything more or less and somehow more successful than with exact data input... even at 2-4km range :huh:

In a fog
 

This technique is more useful in parts than in whole. I use the prop count when I know what the ship is (since it is required) and don't have three minutes to time it. I use the firing solution when you are in a heavy fog and you can't see a ship until your too close to arm the torpedo. That is when I use it the most. If you set the TDC to zero for the bearing, AOB to 90 assuming that is how you lined up your shot, measure your range to bearing line, speed acording to 3'15" rule. The firing line will offset from 0. move the periscope to get the firing line back to zero and that will be you firing bearing. When your sonar operator calls out that bearing fire away. All you will see is the explosion through the fog. You never need to see the target. Okay so the downside is no flag recognition but if you are just off the Coast of England you wont have to worry about sinking an axis ship. The neutrals be damned.

I'm a noob, so bear with me. Could you explain to me point-by-point on how to sink ships in heavy fog? I just finished my first patrol and lost countless merchants due to thick fog...

This thread is so old, but I LOVE the hydro stuff by Dantenoc and Grayrider, Raduz and others. :up:

My tactic for fog
 

This is what I learned from the sound trainer. It is quite helpful.

Once I make sonar contact I set my Sonar Operator to track nearest contact.
Then I make a mark, with the map at 500m, and start my stopwatch. (I use a real one)
After 3 minutes & 15 sec. I make anouther mark. Measure the distance and that is their speed. (600m = 6kts, 900 = 9kts, ect.) It's called the 3min rule.
Now you also have the course. line up at a 90 degree angle to that course.
Come to a complete stop. I try to get to about 500m.
All this time your SO is calling out the targets bearing. this will be vital soon.
Make sure your periscope is set to 0. It does not need to be raised above water, just enough to see the numbers.
Set the speed on the TDC, AOB is 90 either Port or Stbd, and then the distance (ie 500m).
Look at the TDC view, hit the question mark (can't remember what it is called), the torpedo line will be offset from zero. That is your lead. move the periscope that many degrees in the oposite direction. Go back and it will line up with zero ( it will be 345 or 15 or something like that depending on how fast they are going). Make note of that bearing, that is when you will fire. Good time to open your tube/s.
You are ready for action. When you SO calls out that bearing FIRE.
I have not missed with this method.

Some things to think about.
You wont see this target, so you wont know whos side they are on. Make sure you are somewhere at least that is not likely to have axis merchants around. Also if you have downloaded the sound trainer the documentation comes with charts that list vessel types and prop rotation. you know the speed so if you count the prop rotations you can have an idea of which type of ship it is. This will tell you if you will need one torpedo or four to make the kill.
I hope this helps it sure is fun and so far I have not sank any friendlies:dead: (blame it on a mine if you sink a nuetral) Oh and avoid their capital ships after that too.
So good luck and happy fog hunting.

i should probably learn this method but i dont currently use it, for the time being i mark bearing and range either on screen or on graph paper every couple of minutes and compare distance the ship covers to the time it took to cover such a distance, from there i derive speed. depeding on the accuracy of my observations... its usually within a knot. but this is a very challenging and time consuming method.

Yes the 3:15 rule and the nomographs make speed calculations by hydrophone less necessary, but I still use it often as a second opinion. And it just feels so cool to be counting those chug-chugs with a running timer :yep: :lol:

But still the sound trainer and documentation by Raduz is about so much more than just speed calculation. It is really very informative, though a bit too nerdy for some perhaps.

If you take time to do a search on this forum there are some brilliant threads about using the hydrophone to calculate range, bearing and speed at the same time, and to actually sink ships without ever seeing them.

Here is your answer
 

The URL you're searching for is: http://www.subsim.com/subsim_files/patches2005_sh3.html


Enjoy

Great tutorial but i have problems loading the missions included.
I use GWX 3.0, and I did the following includid in the read me file:

Copy the training missions to SH3/data/single missions/english (german/french)

Copy the Sound folder to SH3/data/sound in order to replace the GWX propeller sounds by the stock game sounds.

SH3/data/cfg/contacts.cfg should be replaced by contacts.cfg attached to this tutorial, as the distance reporting used in GWX is not
applicable for methods demonstrated in this guide.

Copy SH3.sdl to the SH3/data/sound


I load the mission for the propellers it loads until like 95% and then crashes to desktop...:damn::damn::damn:

If I remember correctly this mission, or the tables in the PDF were made for a very old version of GWX. 1.02 I think. Since then too much has changed in the ship database, regarding unit IDs and sound modifications that it does no longer work. So far I haven't seen anybody who managed to port this mod up to GWX 2 or 3. It's simply broken for GWX 3

Yes unfortunately.
If I had more time I would make a new table but work and family take up all the time.