Advice for a new player TDC and Hydrophone tracking

[Jonatron5]

I bought silent Hunter 3 on sale and to put it bluntly I AM ADDICTED TO THIS GAME!

I read acouple of guides so far and have started my first campaign from 1939 , I'm with flotilla 1 patrol 2 with a type IIA sub. 100% realism.

While I understand how to use the TDC I feel I need some practice with it especially with moving targets, any advice is welcome.

I am trying to figure out hydrophone tracking as well.

This is the method I have been using (Wich may or may not work)

The hydrophone on my sub has a 20km single ship resolution, so I manually get on the hydrophone (because my crewmen are idiots ) and find a bearing to a vessel. Say for example 035, so I go to my navigation menu and draw a 20km radius circle around my ship, and draw a straight line to the circle at a 035 degree bearing (relative to the bow) and delete the circle, that gives me a line that I know for certain their is a ship on, next I sail 10km(half the distance of the line) at a heading 90degrees perpendicular to the original line, in this case heading 125, then I drop to periscope depth again and get on the hydrophone and listen for a bearing and repeat the process, interestingly enough, the two lines that get drawn usually intercept, and I have been operating on the assumption that is the position of the target vessel.

You do this twice, and you have a path of travel for the target vessel.

Please explain to me if this is totally wrong, and what I should be doing instead of this.

[Jonatron5]

I recently loaded up a mission with the type XXI submarine and tried to use the Sonar For more precise range finding, but it would seem to be in error, every time I click the Ping button it gives me a different range, Whats more, If I click it one per second I get a range increase of 10 meters a second, that means the vessel is doing 19 knots, not likely for a merchant ship, also My map keeping and manual range finding never seem to agree with my sonar officers range, so Im not sure which one of us is correct.

I feel I badly need some fire solution basic training, I understand the logic behind it all, but I Cant seem to get a single torpedo onto target

[Leoz]

A side note for the UZO ...

You can tell distance on the night surface attack run in a simple visual manner.

If viewing a ship from the 90 degree AOB if it is a 78 meter long ship and it fills the width of the UZO, it is about 780 meters away.

Similar: if a 140 meter long ship fills the width of the UZO it is probably around 1400 meters away.

So on many a night attack... where I want some distance between me and the target by the time they start shooting off star-shells. ....

I will fire around the time a 140 meter long ship fills half the width of the UZO or about 2800 meters away... and... use 30 knot speed torpedo settings so I have some good distance between me and them by the time the torpedoes hit.

Also at night, I will often launch torpedoes when the target presents a 90 degree angle on the bow to me. Slowing down or speeding up as needed to maintain the target presenting a 90 degree AOB. The reason is that at night, this AOB is sometimes all I can visually feel comfortable with. Where I may have difficulty determining a 75, 80, 85 AOB.

I punch in that final AOB and fire.

And of course this is for the times I am having difficulty determining their true course or otherwise I would use off-sets with no gyro input to the torpedo.

[Jonatron5]

Originally Posted by Leoz

A side note for the UZO ...

You can tell distance on the night surface attack run in a simple visual manner.

If viewing a ship from the 90 degree AOB if it is a 78 meter long ship and it fills the width of the UZO, it is about 780 meters away.

Similar: if a 140 meter long ship fills the width of the UZO it is probably around 1400 meters away.

So on many a night attack... where I want some distance between me and the target by the time they start shooting off star-shells. ....

I will fire around the time a 140 meter long ship fills half the width of the UZO or about 2800 meters away... and... use 30 knot speed torpedo settings so I have some good distance between me and them by the time the torpedoes hit.

Also at night, I will often launch torpedoes when the target presents a 90 degree angle on the bow to me. Slowing down or speeding up as needed to maintain the target presenting a 90 degree AOB. The reason is that at night, this AOB is sometimes all I can visually feel comfortable with. Where I may have difficulty determining a 75, 80, 85 AOB.

I punch in that final AOB and fire.

And of course this is for the times I am having difficulty determining their true course or otherwise I would use off-sets with no gyro input to the torpedo.

Ok I have been doing alot off practicing, and I have come to the conclusion that my problems with torpedo targeting are 100% a result of poor range finding.

I know this because its too simple to screw up bearing to Target, and if you have an improper range, you get the speed wrong, and you get the lead to Target wrong.

I have ALOT of problems accurately judging range with the attack Periscope., Those lines are very difficult to arrange especially in rough waters and when the master of the ship don't render well at distance.

The sonar seems to be returning bad readings , with a +- 200 meter reading on back to back readings.

I have had moderate success surfacing and using the watch officer to identify it for me, and that seems fairly accurate, but when I chart what he tells me, I get some very strange results on the map, as to the targets course and speed. And even a slight variation will mess up the course down the road and cause a miss.

Any suggestions for accurate range finding?

Just a thought, it could also be my charting, because the compass only measures in 100's of meters, so you really can't accurately plot ranges short of that.

[YellowFin]

I don't know which tools you use, I'm on LSH3 and the GUI that comes with it (the three rings that you can pull down in periscope view and act as various measuring / calculation tools). I had exactly the same problems as you when I started out and I agree, range is the hardest of the data elements to obtain. The following things helped me become better:

• Track target for a good amount of time while overtaking it, keep taking bearings at regular intervals
• Obtain 0° AOB bearing for true heading of target (overtake, and move in front of target to obtain this)
• attack from 90° angle
• use bearings and 0° AOB to get a good speed estimate (say, the 0° AOB line is intersected by the bearings that you took every 30 min 6 times over a stretch of x km calculate the speed x/3 -> km/h, convert to knots

Also the range calculation becomes easier if you get a 0° AOB true heading of the target. Simply sit at a predefined distance from this line at a 90° angle and wait for your target to move in front of your tubes. I usually go between 1.5 km to 500 m

Good luck!

[Joe S]

I haven't played SHIII in a while, been sailing in the pacific lately, but SHIII actually has a sonar operator who can track the nearest merchant or warship. My suggestion is to learn to let the crew do their job so you can be the captain.
In the manual TDC, the most important part of the formula is calculation of the target speed. Plot the position of the target on the map, then measure how far the target travels in one minute. You can then calculate the speed. For example, A target travelling 6 knots will travel 186.16 meters in a minute. Make up a chart ahead of time to consult during the game. Once you know the speed, range is not important. Try shoot the torpedo on a course 90 degrees to the target's track. Set your TDC accordingly. If you shoot at approximately a 90 degree angle, at a range of between 500 and 1,200 meters, with an accurate speed estimation , you should consistently get hits.
Gluck AUf!
Joe S

[Von Due]

Just mentioning one thing that can throw you off easily if you are unaware of it: Rounding errors.

The hydrophone operator will report a bearing but that will almost certainly not be accurate but have in it an uncertainty of 1 degree. While 1 degree doesn't sound like much, it represent an uncertainty in position that increases with distance making any and all plots inherently inaccurate.

This comes down to resolution and how the game rounds off. The bearing is rounded down to nearest whole degree. That means if the operator reports say 273 degrees then 272, then the 272 degree report happens the moment the bearing drops below 273, which for all practical purposes is 273 and not the reported 272. If the report goes from 272 to 273, then the 273 report happens the moment the bearing hits 273.

In short: A bearing report of 273 means the target is anywhere between 273 and 274, report of 272 means between 272 and 273 and so on. The game does not allow greater accuracy than this.

[THEBERBSTER]

A Warm Welcome To The Subsim Community >Jonatron5
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[Pisces]

Originally Posted by Jonatron5

...
This is the method I have been using (Wich may or may not work)

The hydrophone on my sub has a 20km single ship resolution, so I manually get on the hydrophone (because my crewmen are idiots ) and find a bearing to a vessel. Say for example 035, so I go to my navigation menu and draw a 20km radius circle around my ship, and draw a straight line to the circle at a 035 degree bearing (relative to the bow) and delete the circle, that gives me a line that I know for certain their is a ship on, next I sail 10km(half the distance of the line) at a heading 90degrees perpendicular to the original line, in this case heading 125, then I drop to periscope depth again and get on the hydrophone and listen for a bearing and repeat the process, interestingly enough, the two lines that get drawn usually intercept, and I have been operating on the assumption that is the position of the target vessel.

You do this twice, and you have a path of travel for the target vessel.

Please explain to me if this is totally wrong, and what I should be doing instead of this.

Remember that at any time the target is moving. (if not damaged) It has cargo to deliver. It is extremely unlikely that it was at that intersection at that time. As being at that intersection implies it was there at both times, thus stationary. The target is moving away from the bearing, a bit along it but also away from it. If you can make an estimate of target speed (usually 12 knots maximum; the sonar operator give slow, medium, fast.. look in the game config files how fast each is) and consider the time interval between bearings then you know how far apart the 2 valid points on each bearing line can ultimately be. Use a circle with the right radius length and do some trial and error finding points that match. Move the center along a bearing line and locate places that have the circumference touch or cross the other bearing line. This results in areas where the target likely was inside. The better your speed estimate the smaller the area. But with enough areas plotted a path should develop over time.

Target motion analysis the way you did is how modern subs do this. But they have sensors that record bearings at better resolution and at regular time intervals. It is hard to do in the WW2 era. Longer time intervals are needed.

There are several threads and videos describing how to do hydrophone tracking. Search for 4-bearing method in both the Silent Hunter 3,4 and 5 section. It is predominantly a graphical map-drawing exercise.

By being patient and recording bearings, with this tool you can at least figure out where it is going to. (own course, AOB and target bearing is enough to figure target course) It does not give you speed or range. That needs other methods. http://www.subsim.com/radioroom/showthread.php?t=147719

But simply chasing a target by moving fast along the bearing (doing regular hydrophone checks) should also get you near. Close enough to start plotting positions on the map. However, you are using a type-2 though and that has limited speed-advantage over merchants. You can get most, but some might be lost. Especially in bad weather.