Target speed calculation made easy

[lms_oid]

Originally Posted by RedHammer

i try again and again but the numbers are just way off. Cant hit anything.

Try the third mission of the naval school. You should find a speed of 9 knots for your target. In order to find this result you must :

- Identify the ship in the recognition manual and validate in order to send the mast high which should be aroud 75 to the Stadimeter.
- If this is correctly done, you should find a range of about 1000 yards with the stadimeter. Validate this info to send it to the TDC.
- Set the angle of bow to 90° on the right (which is approximately the case) and send again the info to the TDC by validating.
- Check the bearing and launch the chronometer for 10 seconds. You should note a bearing change of about 3° during those 5 seconds.
- By using the table I provided, you can see that the speed of the target for 1000 yards / 3° should be 9 knots. Set the target speed to 9 knots and validate to send the info to the TDC.
- Congratulations : You have entered a valid solution in the TDC!
- Launch the tropedo and it WILL hit!

Remark 1 : By playing this mission with manual TDC disable, you can see that the speed of the target IS 9 knots, so if you find 9 knots manually, you are right!

Remark 2 : Don't forget to VALIDATE (by clicking on the button) each info you gather or you enter in order to send it to the Stadimeter or the TDC. If you don't do that, the TDC won't be updated with information you've gathered and the torpedo will go everywhere but not on your target.

lms_oid

[Von Hinten]

First of all a thanks to lms_oid for this lovelt table. I'm sure that it'll come in handy and I will definitely try this out.

Originally Posted by Shigawire

The 3 lines at the bottom is the nomograph. If you know any 2 values of the 3, you can discover the 3rd unknown value. If you know time traveled, and distance traveled, you can find speed. If you know speed and time traveled, you can find distance. All you need to do is make a line between the 2 known points, and the line will cross the 3rd line where you will find the value you were looking for.
Quite ingenious.

Would you believe that I've looked and looked and looked again at those lines and never knew what they were there for? I feel so silly at some times.

Much to learn, this young one has ... hmm?

[RedHammer]

Originally Posted by lms_oid

Try the third mission of the naval school. You should find a speed of 9 knots for your target. In order to find this result you must :

- Identify the ship in the recognition manual and validate in order to send the mast high which should be aroud 75 to the Stadimeter.
- If this is correctly done, you should find a range of about 1000 yards with the stadimeter. Validate this info to send it to the TDC.
- Set the angle of bow to 90° on the right (which is approximately the case) and send again the info to the TDC by validating.
- Check the bearing and launch the chronometer for 10 seconds. You should note a bearing change of about 3° during those 5 seconds.
- By using the table I provided, you can see that the speed of the target for 1000 yards / 3° should be 9 knots. Set the target speed to 9 knots and validate to send the info to the TDC.
- Congratulations : You have entered a valid solution in the TDC!
- Launch the tropedo and it WILL hit!

Remark 1 : By playing this mission with manual TDC disable, you can see that the speed of the target IS 9 knots, so if you find 9 knots manually, you are right!

Remark 2 : Don't forget to VALIDATE (by clicking on the button) each info you gather or you enter in order to send it to the Stadimeter or the TDC. If you don't do that, the TDC won't be updated with information you've gathered and the torpedo will go everywhere but not on your target.

lms_oid

I cant get any bearing change on the position follower unless i input a speed value in the tdc. Besides there are no numbers, only small little lines. So I cant even count it accurate. Sorry for the trouble, and thank you for answering so quick earlier, I guess I am just getting frustrated by this issue, having to spend 2 days to learn other methods of getting somewhat accurate speed and aob into the tdc is a pretty steep learning curve, and sure does cause alot of stress.

S!

RH

[lms_oid]

Originally Posted by RedHammer

I cant get any bearing change on the position follower unless i input a speed value in the tdc. Besides there are no numbers, only small little lines. So I cant even count it accurate. Sorry for the trouble, and thank you for answering so quick earlier, I guess I am just getting frustrated by this issue, having to spend 2 days to learn other methods of getting somewhat accurate speed and aob into the tdc is a pretty steep learning curve, and sure does cause alot of stress.

Don't be frustrated, everybody has to learn and I don't know many games where you have this kind of work to do (IMO, SH manual TDC is really realistic).
If 10 seconds is to short, you can still use the formula I gave earlier with T=30 seconds or more. But by zooming (mouse wheel) and by locking the target using 'L', you should be able to estimate the bearing change for 10 seconds.

lms_oid

[RedHammer]

rgr. I think I found a way to determine bearing,
First I find the mogami in the recognition manual, input it to the tdc.
then I went to the map, and drawed a line from the Mogami`s stern to maybe 100 meters in front of it. Then I took the Compass, and clicked in 30 yards away from the end of the "100 yard" line, which the Mogami will reach within x amount of time, and i expanded it, and then made it so it pointed against my sub. Then I took the protractor at the exact end of the 100 yard line and to the 30 yard away from end. and then to my sub, I had a value of about 63 degrees to his Starboard. Which is then, AOB, then I hurried up and got range and speed into the TDC.

I repeated the above AoB trick I just did, and thus, I managed to calculate AoB within 30 seconds. Which was about 3 degrees in 30 seconds, give or take.

Finally! All 4 torpedoes hits at exact same place on the Cruiser, and he goes down quick!


Thanks alot for the solution

S!

RH

[RedHammer]

uhm nevermind, that method i just mentioned didnt work, i got too much of a bearing change for the speed to be correct..

So what you are saying, is that I have to check the bearing change by Visual Eyesight? How will I be able to see, with my own eyes, thru a periscope, at 1100 yards, if he changes his course by 3 degrees?

Getting frustrated again.. Ubi.. please fix the auto bearing finder..


S!

RH

[tedhealy]

Thank you much for the table

[Nightmare]

I'm wanting to use the plot over time, so I'm making my drawings on the nav map. What's the formula to figure out speed using this method? I'm also using imperial mesurments.

[lms_oid]

Originally Posted by Nightmare

I'm wanting to use the plot over time, so I'm making my drawings on the nav map. What's the formula to figure out speed using this method? I'm also using imperial mesurments.

Say you have plotted a move of 0.6 nm in 3 minutes. You now know your target is making 0.6 nm each 3 minutes. Since there is 20 times 3 minutes in an hour, your target speed is (0.6 x 20) knots (since 1 knots = 1 nm per hour). So your target speed is 12 knots.

lms_oid

[Barkhorn1x]

Thanks for this - I took your table - and the methodolgy comments and made a nice reference sheet out of them.

[lms_oid]

Originally Posted by RedHammer

uhm nevermind, that method i just mentioned didnt work, i got too much of a bearing change for the speed to be correct..

So what you are saying, is that I have to check the bearing change by Visual Eyesight? How will I be able to see, with my own eyes, thru a periscope, at 1100 yards, if he changes his course by 3 degrees?

Getting frustrated again.. Ubi.. please fix the auto bearing finder..


S!

RH

I know what you did wrong and in fact I was doing it wrong to!

The time you spend entering the AOB and estimating the speed, the bearing changes! And the bearing is only updated in the TDC by the synchronisation button on the stadimeter (first tool of the 3)! Just before launching the torp with AOB and speed set, you should go to the stadimeter and send another time the infos to the TDC or the bearing information in the TDC will be false and you will fire behind the target!



On the video below, you can see that just after entering speed, I launch the first torpedo without re-updating the bearing in the TDC. And just after that I launch a second torpedo with bearing updated. The two torpedoes take very different route and the first one miss but not the second one!



lms_oid

EDIT :

Reading again your last post :

Originally Posted by RedHammer

How will I be able to see, with my own eyes, thru a periscope, at 1100 yards, if he changes his course by 3 degrees?

I realize that you don't know what is the bearing I talk about! There is no link at all with the course of the target! It's the number you can read at the top of the screen when using the periscope. You should be able to read that!

[Rykaird]

Originally Posted by lms_oid

Say you have plotted a move of 0.6 nm in 3 minutes. You now know your target is making 0.6 nm each 3 minutes. Since there is 20 times 3 minutes in an hour, your target speed is (0.6 x 20) knots (since 1 knots = 1 nm per hour). So your target speed is 12 knots.

lms_oid

Thanks very much for this simple explanation of how the equivalent to the old 3:14 rule works!

[Nightmare]

Originally Posted by lms_oid

Say you have plotted a move of 0.6 nm in 3 minutes. You now know your target is making 0.6 nm each 3 minutes. Since there is 20 times 3 minutes in an hour, your target speed is (0.6 x 20) knots (since 1 knots = 1 nm per hour). So your target speed is 12 knots.

Thanks you! This should help tonight when I practice a little more. I was using Neal's method of using roughly half the targets max speed with some minor tweaking.

Another thing I found is there is a button in the lower right corner of the position keeper (just to the right of the position keeper/torpedo settings switch). Once you take your range, AOB, and speed and enter them into the TDC, hitting that button will set the TDC to track. In theory, if you are accurate with those three things, the TDC will keep an accurate firing solution and update the torpedo gyro angles continually.

When I'm ready to fire I:
1) raise the scope
2) check if the generated bearing in the TDC matches (or close to it) the bearing from the scope.
3) check to see if the generated AOB in the TDC matches roughly with what I see in the scope.
4) take one last range and submit to TDC and see if the generated range was off.
5) If all those things check out, it's time to shoot!

[micky1up]

why not have the sonar report the rev count of the engine and have a TPK (tuns per knot) for each vessel ie a battle ship has a tpk of 8 and the rev count is 80 therefor the speed equals 10 kts

[lms_oid]

Originally Posted by micky1up

why not have the sonar report the rev count of the engine and have a TPK (tuns per knot) for each vessel ie a battle ship has a tpk of 8 and the rev count is 80 therefor the speed equals 10 kts

A very good way indeed, well known by SC or DW players! I didn't tried that in SH4 (only 3 hours of play and I'm leaving tonight for one week skiing holidays), is it working? Can you ask the sonar to do that? It would be great!

lms_oid