I have a bit of a specific question.
I understand most of the logic described in the above posts and have been putting it in practice pretty accurately. However I almost always have problems when the contact is travelling almost directly towards or away from me (something like <20 degress and >160 degrees to the LOB). In these cases my solution is pretty much way off.

What I currently try to do, is get some kind of range by increasing speed to 10knts+ perpendicular to the last LOB and using the point where the bearings cross as the range. This gets me some kind of accuracy if the contact is close (like 20-30 kyrds). The only trouble is that now that I've hit the throttle so close to the contact, he knows I'm there and tries to hit me with something.
Also, at longer ranges, the point where the LOBs cross becomes a bit "mushy" and I frequently end up with a 20-30kyrd stretch of water where the contact might be.

The other problem I face with the above is that I usually cannot figure out whether the contact is coming towards me or going away.

Does anybody have any advice on how to deal with this kind of situation?

Your sonar tell you if its going away or forward
it's easier with a waterfall of course.
using history will tell you quite well if the contact close or not.

If you already ensured all LOBs were very close from each others (contact closing or moving away), after 3 or 4 confirmed LOBs :
take a perpendicular course as you said, and watch carefully the sonar

If signal increase, the contact is closing you
In this case, stay in the same layer : the ennemy sub could only see you with the spherical, and go 120° from the contact, both to keep distance (and so avoid detection) and to refine TMA.

If ennemy is going away (sonar signal decrease), be carefull => ennemy could catch you with TA if you increase your speed => change layer, then go to the ennemy bearing at combat speed in the other layer than the contact.
regularly (depends on situations), change your course to 60° from the previous contact, go slow and very quiet (you are the hunter as long as not detected), and change layer to catch again the contact (with short TA -1/3- to accelerate the process).
Once you've found a good position to work, stay at the same layer than the contact, at slow speed, quietly, to make a TMA.

When ennemy is going away, it's harder than when it close, because you need to go after him.
When he come right to you, it's the best way for you to calculate a nice TMA on him when he don't even know you are around !

That's why subs never go straight :roll:

Are there any good tricks in DW that you use for TMA that wouldn't immediately figure out?

With my background working in OR, I tend to think of everything as a math problem and try to construct a toy tactical decision aid. While that has some usefulness, sometimes I wonder if I'm neglecting the simple answer. :-)

I wonder how many 'tricks' past and present Fleet members will contribute ? Promotion and places on advanced
courses have to be earnt. That such information is regarded as a golden key conferring an edge is a fact of life !
One Fleet had a very bright serving sonar officer i/c an advanced course imparting tricks of the RL trade !
I regret that there may be some reticence in answering this excellent question.

To what extent past and present individuals with RL experience are free to expand on TMA material, much of which,
is in the public domain is unclear. However I join SeaQueen in hoping that sources from any legitimate
quarter may expand the general understanding of some techniques !

For instance does anyone feel able to expand on the subject of anchor lines ? A topic which should
be expected to develop naturaly from remarks in this thread about manouvering relative to a target.
Or will this remain an ace up the sleeve ?

I hope I share with many the desire to progress within fair competition and not by means of using
information unavailable to new players ! Liberty, Equality, Fraternity !