Fast 90, where am I going wrong.

[Hambone307]

Well Knight, this was an interesting derailment of a thread related to needing help with an attack tactic. I had tried to use the 90 degree method the other day after seeing your initial question and had probably a 40% hit ratio. For some reason I kept shooting behind the merchants, and couldn't figure out the issue.

[Kip336]

Knight I'd almost go as far as saying that the S class I'd bugged. I ran Into one, many 8.8cm and flak later it did not sink. It was in the harbor so I shot off his deck and flack guns and proceeded to take my time at sinking her with below the Waterline hits.

[knight76]

Hambone307 - I think my issue was probably with my timing the ships for speed. I was using 3 minute flat, so that would have thrown the speed out a little, and I generally don't get my ship lined up perfectly on the 90 degree line, the target tends to be a little off my plotted track by the time it gets to the intended shoot bearing.

This probably combines to mean my torps trail the target slightly. On larger ships I still score hits, just further back than I aimed, on smaller ships, I may miss just aft.

I haven't had a great deal of time to practice the attack as each lone merchant I find is not armed and I sink them with deck guns.

I have found though, that shooting from 500m rather than 1000 cuts the error down a fair amount also.

Kip336, has to be bugged. I easily hit the S type with 20 shells total, mixed above and below the water line. I didn't notice any adverse effect at all.

Just stumbled on a slow/stationary ship in the water off the coast of england. I read the flag wrong thinking it was yugoslav but it turned out to be a neutral. Anyway, this ship was a depot ship, armed all over and in war paint, funny a neutral country ship, anchored off the coast of england, armed to the teeth and in war paint, I called bull**** and sent it to the bottom. Will take a renown hit though. It got me thinking though, I wonder if there are U-boat trap merchants in the game. I've never seen one.

[Zosimus]

Originally Posted by Pisces

I never personally called you a cheater. I did however say that the way the game displays the hydrophone bearings on the map, both in direction and length is cheating reality. This is of course not in anyway "bad" because SH3 is a game, and by definition it does that. SH3 is not a real simulator. And even simulators cut corners sometimes. So there is no need to feel threatened or consider your self attack as being a "cheater". If you want to play with the tools that the game gives you then that is OK and fine. I'm just saying in reality is wasn't so easy and reliable. Which I will explain next why I think that, based on the document you linked to. I have read it! In fact, I think I was the first one* that introduced it the SH3 forum to it by linking to this writer's site:

http://www.subsim.com/radioroom/showthread.php?t=130404

*: Ok, I forgot it was linked in the GWX 1.03 manual.

Why is the precise direction of the plotted bearing line 'cheating' reality?

Well if you read that document then you'll find that the bearing preciscion was very dependant on the frequency of the sound. Only with the higher frequencies (above 3 khz) could you get bearing precision narrower than 1 degree. Lower frequencies (in the order of 500Hz) give a much 'fuzzier' bearing, making the actual bearing somewhere in a range of up to 8 degrees. Which would make it a lot harder to find the center of the sound, just like listening to the sound manually at the station. And as higher frequencies decay in strength much sooner than lower frequencies these bearings would not have been as accurate at long range as the game portrays. Page 15 of the document you linked:

The question remains then how much this amplifier could enhance the higher frequencies without distorting the signal or flood it in self generated noise making it useless at longer ranges. This is hard to verify so long after the war, without first hand experience of the operators written down. (one of the conclusions of the writer)

Range determination based on hydrophone

The other place where I used the word cheating was in relation to the length of the hydrophone bearing line on the map in the game. Which as we know has the faint end of the line exactly ending at the source of the noise detected. Your eyesight, screen settings and antialias settings of your videocard determine if you get the right pixel spot on.
You state that the GHG or hydrophone had a resistor with which the signal strength could be reduced to determine the range of the source. You suggest that this variable resistor could be adjusted to get an absolute value on the range. Or at least get steps of 500m if it had 40 intermediate steps covering an expected max range of 20 km. However, I read that section about the resistor differently:
Page 3 of the PDF document:


"could indicate the increase or decrease of the sonic signal strength"
- I read that as it could indicate a relative change in signal strength, and hopefully by relationship, distance.
What this means is that this resistor control could indicate if the sound source got stronger or weaker than to what it was calibrated. It does not say to which range it was calibrated. Which would require a known distance under the same conditions, which is something you don't have when you haven't located the target yet. In fact the writer mentions it is calibrated to a ohms value, not actual distance. And indicates that this can work upto 20-25 nautical miles, depending on the conditions. So, with background noises changing daily, or maybe even hourly due to the weather and internal conditions, this cannot be considered an indication of absolute range. It's only relative, and at best an indication of how much percentage wise the distance closed or opened up. That's why I feel the line length of the hydrophone bearing is not supposed to indicate the exact position. There is not enough variability in it to match the real world.

So, if you want to play the game as it is given then you should not feel offended by me using the word cheating. Especially as I wasn't personally addressing you. I'm just saying it lacks quite a bit in terms of realism, which understandably the game does not provide on all accounts.

Play as you like.

Only to a limited extent would I agree with you.

Certainly SH3 is a game, and the game does not accurately model reality. A surfaced submarine, for example, traveling at 8 knots should still be able to detect a medium-sized target at 5,000 meters (see https://books.google.com.pe/books?id...ophone&f=false ). Personally, however, while traveling surfaced in the fog in SH3 the first notice I get of nearby vessels is when the destroyer shoots me twice before ramming into me at high speed.

Were you aware, for example, that by turning broadside to the ship the accuracy of the GHG was greatly increased? Turning broadside to the ships does not, as far as I know, improve the accuracy of the hydrophone in SH3.

Or perhaps you think that the GHG in SH3 gives one GPS-like location-finding ability. It does not. Play a bit with map contacts on, maneuver underwater until you close to within 5,000 meters of a ship. Zoom in as much as you like and put a big X on the location the GHG places the ship at. Then go scope up. Whoops!! The ship isn't where you thought it was.

The point is, however, that GHG shortcomings have a tendency to cancel out.

Imagine, for example, that your intrepid crew believes (falsely) that a ship that is 10,000 meters away is really 8,000 meters away and that the second bearing you take, when the ship is 8,000 meters away, falsely shows up as 6,400 meters off. I think if you break out your drawing tools that you will find that the course still ends up close to the real one.

Similarly if you hydrophone operator mistakenly believes that the signal is some 5º higher than it really is – i.e., that a ship that is really at bearing 30º falsely shows up as 35º – that when the second bearing is taken falsely showing the ship at 55º when in fact it's at 50º that the ship's heading still comes out close enough for government work.

You can move into position, get visual contact on the vessel (by periscope), adjust your firing solution, and hit it with a two-torpedo salvo more often than not.

[Zosimus]

The following is an extreme example of error using hydrophones.



The top line, at 100º heading shows the true course of the ship we are hoping to track. The bottom line, which is shown by two marks 1.0 apart, shows our course. We assume that we are submerged, running silent, at 2 knots. We cover 1000 meters in 16 minutes 12 seconds. During the same time period, the target ship covers 3500 meters @ 7 knots.

The real range of the target is 18 km at the moment the first hydrophone contact is made. However, since we are exaggerating the error, we assume that our not-so-skilled hydrophone operator mistakenly places the ship at 9 km distance. In short, the ship is twice as far away as we think it is.

At the second point, the ship is 16 km away, but our hydrophone mistakenly gives us 8 km distance. Using these two bearings and ranges, a course is plotted. We calculate that the ship is heading 95º when in reality it is heading 100º

We surface and move full speed (heading 5º) to intercept the ship, moving at (we assume) 14 knots because of weather. As you can see, even with this extreme error in distance, we are still very close to getting it right. As soon as visual contact is obtained, we will be able to adjust our course and set up a firing solution.

[DownPeriscope]

Alternatively, as opposed to the 3:15 method, assuming you have GWX installed, you can use the nomograph on the right hand side in the navigation map for any time period you find convenient - though obviously the longer the time the more accurate it should be. Using the nomograph is really easy - just draw a line between the 'time' and 'distance' mark to get the speed in knots

You can also try the four bearing method. This is also useful when you don't have visual contact and are relying on hydrophones, esp. without map contacts on you won't be able to judge distance

Here is a pretty good explanation of the four bearing method:

http://ricojansen.nl/downloads/the_f...%20Kuikueg.pdf

Note that it doesn't tell you exactly how to construct the paralell lines - I use a combination of compass and protractor for that (there should really be a T-square tool in this game :-)