Good technique for tracking escort targets -- SONAR Only -- No Map Updates

[Dignan]

Does anyone have any good techniques for sonar only tracking of targets when escorts are present (with No Map Contacts enabled)?

I've been on a 'no map contact update' kick lately and am familiar with tracking targets via sonar (pinging) to establish a course and speed. But what do the expert Captains on this board recommend for sonar only tracking when escorts are present? Obviously you can't ping for range when escorts are listening? ANy tips?

Thanks.

[kstanb]

I am not an expert, but for what I read the best advice is to avoid it completely and get used to stadimeter instead; (there are mods that expand the zoom capability making stadimeter reads a lot easier to do), you can also start a career when radar is available.

The problem with sonar is that you won't know how proficient is the escort crew you are facing; if it is a green crew, and sea conditions are poor, then they might not get you, but if they are proficient, chances are they will go after you.

[Dignan]

I am not an expert, but for what I read the best advice is to avoid it completely and get used to stadimeter instead; (there are mods that expand the zoom capability making stadimeter reads a lot easier to do), you can also start a career when radar is available.

The problem with sonar is that you won't know how proficient is the escort crew you are facing; if it is a green crew, and sea conditions are poor, then they might not get you, but if they are proficient, chances are they will go after you.


That's what I was afraid the answer would be. Thanks for the advice. I also considered the possibility of doing a surface attack if the fog was heavy enough or it was night+fog. Then you could use the radar to plot a course and speed.

[Platapus]

2 IFs

If you are stationary and
If the game was equipped with a proportional divider, you could track rather well using just sonar. You would be able to determine course and get a pretty good idea of speed. But you need proportional dividers. I sure wish the game had them or someone could mod them in the game.

You could try to do it on paper but a good set of proportional dividers will run you about $200.00.

Without those two "IFs", tracking on sonar in the game is difficult and you will probably lose your target.

I am working with one of our mathematician brains at work to work out some trapezoidal formula. We are trying to generate a procedure to determine speed, course, and range by making long range bearing only sightings but I am sure it could work with sonar too. As soon as we have something I plan on making a post on our results.

[Dignan]

I look forward to those results. I assume you've already stumbled across the "4 Bearing Technique" in the SH5 forums? If not, do a search for 4 bearings technique there. I think it may be the traphezoidal technique you are referring to. To be honest, I've tried to learn it several times but felt like I was back in calculus or advanced geometry class and I gave up....because subsims are about having fun, not doing complex math problems.

If you can simplify the process I'm all ears though.

[TorpX]

Yes, there have been at least a couple sonar only techniques posted on the forum. I've never tried them, though. They didn't strike me as being all that practical.

[Sailor Steve]

Prior to the war the sonar-only attack was recommended. Here is the reality:
Only 31 of the 4,873 attacks analyzed after the war could be described as "sound" attacks, and none of these were successful.
http://www.hnsa.org/doc/subsinpacific.htm

So the "sonar-only" attack in any game is 100% unrealistic.

[Loudspeaker]

Nowadays they determine ship class and speed by listening to the propellers only. Knowing target speed AND bearing makes it easy to dertermine range and course. Perhaps some of you know this technique from SSN688(I) Hunterkiller?

I have been trying to work something out based on the few facts provided to you by your sonarman:

1) Bearing
2) Speed: fast, medium or slow (approximately 12+, 9, 6)
3) Target moving away or closing

Problem is, this is a time consuming method. Just as you are beginning to get a clue, what is going on up there, your target is already anchoring in Tokyo Bay. Not to mention the frustrations coming with the target simply altering its course and makes you feel like an idiot.

[Dignan]

the only way I could see this working is if the target is heading towards you for the most part.

For example, if you take a few bearings and determine that the target is moving from your port to your starboard then start moving towards the sound contact and to your starboard. Keep doing this and taking bearings until the bearing readings become static. This would indicate that the target is coming directly at you (or perhaps going away) Once you determine that the target is coming directly at you with no change in bearing (and you are not moving) then you know its course. There are a lot of "IF"s in there though. The target has to already be heading towards you and you have to be lucky enough to get right into the path of it and stop.

Just theorizing.

[TorpX]

Problem is, this is a time consuming method. Just as you are beginning to get a clue, what is going on up there, your target is already anchoring in Tokyo Bay. Not to mention the frustrations coming with the target simply altering its course and makes you feel like an idiot.

This is my thinking. The USN manuvering board manual had a problem of this nature where one was to calculate the course and speed of a ship from bearings only. It was not phrased as a submarine attack problem, but rather as a problem with a ship located from radio signals or the like, so it is possible.

In ordanary circumstances, it's hard to see any advantage to making an approach in this way. Submarines had periscopes and later radar, so a sonar only approach was unnecessary.

[Nisgeis]

So the "sonar-only" attack in any game is 100% unrealistic.

Especially as the speed of sound in game is instantaneous, so there is no bearing lag from the sonar picking up sound from where the target ship was - an error which gets larger with target speed and high AoBs. This does make it much easier to do an attack as you get optical-like accuracy for sound bearings.

[TorpX]

Good point. Sea conditions should have much more effect than it does in game. It's too bad; this aspect of the game had great potential.

[in_vino_vomitus]

I have a perverse thing for avoiding the easy option [up to a point], so I usually play 100% realism, and I usually start a campaign in Dec '41. I had great difficulty with the 4 bearings method, but I've worked out a way to establish course, speed and position from sonar bearings only, using MOBO. [A thousand thanks to aaronblood].

Anyway, I've searched unsuccessfully on here for something similar. I find it hard to believe that nobody else is doing this, and I'm pretty sure my method has loads of room for improvement, but if anyone's interested, I'll try to put a tutorial together.

If anyone knows of such a tutorial on here already, I'd be grateful for a pointer. As I say, I'm pretty sure my method can be improved....

[J.E. McKellar]

Lurker piping up here-

I've tried this once or twice, with not much luck, forgot to imput the bearings into the TDC.

I started off with a long-range visual contact, so I knew the basic position and course of the target, and the layout of the convoy. I picked out the light cruiser in the middle to track, because it was easier to isolate her screws from the others. Every three minutes, I would find the bearing from passive sonar and use it to draw a line from my sub's current position. After several measurements, I had several lines radiating out from my slowly moving sub.

Assuming that the target is moving at a constant speed and course, the target's course should intersect those radiating bearings at constant intervals, i.e. the distance from bearing 1 to bearing 2 is the same as the distance from bearing 2 to bearing 3. So I just eyeballed a line running across the bearings that seemed to match pretty well, and then used the compass to double-check and adjust the line.

Now that I had the course figured out, a new bearing reading would give me the distance and AOB, and measuring how far the target traveled over those 3-minute intervals would give me the speed.

After that, you just have to work as a sort of manual TDC, taking more bearings at finer time intervals to make sure all your numbers make sense, and that the target isn't doing anything unusual. Even then, a quick check with the periscope right before firing is necessary to get a precise fix.

[Sailor Steve]

WELCOME ABOARD! :sunny:

I like your method. Unfortunately I have problems with calculations beyond 1+1, but your description is easily understood. Thanks for putting it up.

Even then, a quick check with the periscope right before firing is necessary to get a precise fix.
That's always the crux of the problem. You can't be precise with sound only. You always need to look.

[in_vino_vomitus]

The thing about sonar, is that it's going to pick up the target a long time before anything else, even when your boat is equipped with radar, so you can begin gathering data on your target long before you pick it up by other means. hydrophone data is less accurate than radar, but it's plenty accurate enough to begin manoeuvring long before the target's in visual range. It's highly labour intensive though. By the time I actually see a target I'll probably have three or four moderately different solutions for course and speed. But it means that when I make visual contact I'm at the point of putting the final touches to a firing solution, rather than just starting out. Sometimes I can have a course and speed roughed out from hydrophone data before I pick them up on radar.

As I say, it's labour intensive and I'm lazy. A lot of the time, once I get radar to play with I forget about the hydrophones, but in the early days, when radar isn't an option, the difference they make is huge...