Hydrophones only, course speed and position.
 

Disclaimer: I'm not arrogant enough to believe that I've found something new or that I'm doing this better than anyone else. I've looked for info on here so's I can improve this technique. So far the only thing I've found is a PDF of a navy TMA manual that scares the stuffing out of me with mathematical formulae. This is as much an appeal for info as it is an offer to share....

So. I am a long way still, from being good at this, I'm not saying otherwise, but my determination to play the game out from day 1, plus my lemming-like attraction to enemy ordnance, means I spend most of my game time minus radar. A problem for me therefore, was to locate targets using nothing but hydrophone data.

It's pretty easy to head towards a sound contact at speed until you pick it up visually, and it's pretty easy to do the 4 bearings thing from a static position. What I wanted was a way to head towards the target and calculate its vital statistics on the move, so that by the time I acquired it visually I pretty much had a firing solution.

I couldn't get the hang of the four bearings method. not consistently enough to make it worthwhile anyway. Eventually I downloaded MOBO [by the way, there needs to be an option to buy someone a beer on here. There are a few people who've earned them....]

OK - so using MOBO I've come up with a method to calculate the course speed and position of a target from a moving sub. I'd say it's moderately accurate. It means that without radar, by the time you have a visual on the target, you already have most of the information you need for a solution. I have on occasion, had this info worked out before acquiring the target on radar.

Anyway, as I said, I'm not arrogant enough to think that no-one else has done this first, and I'm aware that even if that was the case, it probably wouldn't be of much interest. BUT...... If anyone knows of any info on here that would help me improve this, I'd really appreciate a pointer. If anyone wants some more info I'd be happy to share. The only reason I haven't gone into detail is that it's finicky in places and pictures would work better and even with pics it would mean a lot of typing.

That's the way the sub skippers were instructed to do it in the early years of the war.

You may find these YouTube videos of interest:

Part 1: http://www.youtube.com/watch?v=eAt5cAfeL9c
Part 2: http://www.youtube.com/watch?v=w1m_vwkG2Ac

There was another video from WernerSobe that addressed this topic but the audio was muted for some stupid false copyright claim.

Sorry, I can't stream videos at the moment - I'll check them out as soon as I'm able. I've seen several sonar only tutorials, including one by Werner, but all of them have been either close range stuff using active sonar, or 4 bearing plots from a stationary sub. I haven't yet found anything about long-range passive tracking from a moving sub, apart from the 4 bearing method - and that I almost never got a useful result from. Probably because of something I wasn't doing right, but I never worked out what it was

If you do maneuvering board type plotting, there is a simple procedure by which to do this that you can do in-game without resort to having to use MoBo (which is a really great tool). Of course the procedure contains certain assumptions about the target and your sub, but it works given those assumptions.

Basically, you construct two sets of congruent triangles with each of your two sets of three bearings (taken at two different sub courses and speeds) so as to triangulate the target. Doing this you can get its course, speed and position as of the final bearing taken. It's like the 4 bearing method, only you don't stop with 4 bearings.

I don't know why more people don't do maneuvering board solutions. It's easy to do in-game with no extra tools (save maybe a pencil and paper to write down basic observations) than you have in stock, other than having a nomograph on the nav map. You aren't locked in to having to try to be fast to plot based on where your moving sub icon is on your map. In fact, if you just write down your observations you don't even have to plot as you go. You can figure out what you want as needed.

I play using a pencil and paper to write down observations and the is/was I made using components printed from a pdf that can be found here. Other than that everything that really needs to be done can be done with teh in-game nav map tools. MoBo is great and is very useful, but I just got tired of tabbing out to use it. After becoming proficient at generating maneuvering board solutions I found I didn't need it anymore.

Creative use of the tools available gives you all you really need to do the vector operations that can do everything from track targets to graphically figure out firing solutions. If you understand the PK you can use it as a calculator as well, but often the PK is employed in other work when I want to do some figuring so I do it graphically.

[QUOTE=sckallst;2069921]If you do maneuvering board type plotting, there is a simple procedure by which to do this that you can do in-game without resort to having to use MoBo (which is a really great tool). Of course the procedure contains certain assumptions about the target and your sub, but it works given those assumptions................

This sounds useful, but the method isn't obvious from your description. Can you give me some detail?

It's one of those things that somewhat simple overall, but a real bear to explain with anything approaching brevity. And that's without getting into all the interesting tactical/practical side discussions.

It may be best if you download the Maneuvering Board Manual from here. You can just download Chapter 6 if you like.

http://msi.nga.mil/NGAPortal/MSI.por...2&pubCode=0008

Example 25 in Chapter 6 lays out the procedure for COURSE, SPEED, AND POSITION DERIVED FROM BEARINGS ONLY. If you have questions I can follow up.

I'll do that - thanks for the pointer :)

:salute:
Excellent link, thank you.

Is there a visual or video on this method, please link it here

Try
4-Bearings Technique Tool

and
The four bearing method

The original post from a SubSim member has a bunch of dead links, and the first two links of that 2nd post in the 2nd link above are also. Notice also that the mods linked to in that posting are for SHIII, except Sublynx's drawing, which is a universal Utility.

Thanks for reviving this thread!



The Mobo utility is a separate program so you can run it besides any game. The only problem was that it requires one to alt-tab out of Silent Hunter and the game doesn't like it. I don't know if this thing is still downloadable anyway, it's been over 10 years but I still have a copy somewhere.

By the way, the 4 bearings method doesn't require one to be stationary. The 6 bearings Mobo method uses basically the first steps of a 4 bearing method that you repeat on 2 different headings. It's incredibly satisfying but AFAIK ww2 sonars were not precise enough to do it, both sonar-only methods were devised after the war when Allied subs switched to hunting submerged subs rather than attacking surface ships.

Is this the one you are referring to Kpt. Weyprecht MoBo - Electronic Maneuvering Board from Aaron Blood?? It is way cool... though all too often, beyond my pea brain's ability to wrap around it and understand the skills to use properly.

Yeah, that's it! It's brilliant. It can be complex because it combines maneuvering board and drt features, so you can be looking alternatively at relative motion or the usual geographical plot. At the time, I was going through the Publication 1310 for the basic mobo (the Bowditch also has a chapter on the use of it).

Most of the time, I was just calculating intercepts. I would create a fictional contact offset to the firing position then calculate an intercept for it, so that I would be perfectly positioned to shoot.

For hydrophines only, the Mobo has a TMA fimubctiobality, although I don't think I ever used it.

Oh, and waay back in time there used to be a mod to have you TMA bearing lines automatically drawn on map byu it was ancient and would probably not work with any current suoermox