TMA, no DEMON, no LOS switch

[NFunky]

Hey all,

It seems the more I learn about sub vs. sub tactics, the harder a time I'm having balancing good tactics vs. good (and fast) TMA. I recently read an old thread in which it was stated that if two subs are tracking one another and one changes its LOS (from lead to lag or vice versa) that its range is about where the next bearing line crosses. I've tried this tracking AI subs and it definately works quite well.

When I didn't have DEMON info (when a contact was too faint for a BB tracker), I used to switch my LOS to get a quick, rough solution. This worked, but I'm now realizing that, were I playing a good human player and not the AI, I would have basically just given him permission to shoot me. Thus recently I've stopped doing an LOS switch unless I have to or from lead to lag right before I fire. I've been having some luck making 30-90 degree changes in same LOS for TMA legs, but I've been having to pretty much guess speed. I've been finding that if the target zigs anytime before I have a damn good solution, I end up with a terrible range estimate.

So, do any of you pros out there have any advice on obtaining a good, fast TMA on a target without DEMON data and without giving away my own range.

[ASWnut101]

Use a Seawolf. :DL

If you don't, well, you're going to have to compromise eventually. In a sub v. sub fight, unless you are in a 'wolf and he's in a Han screaming along at 25 knots, you pretty much have to assume that he sees you and is trying to get a solution on you. And the first to get a solution and fire is usually the first to win. A winning fight is one where you can walk (swim?) away and he can't, 'cause he's in a thousand pieces scattered across the seafloor.

Get up to tactical speed, put him on a lag LOS, and keep making new TMA legs to keep him on his toes while you get a solution. Once you've got that solution, fire at the best tactical moment (very situation-specific), which may be as soon as humanly possible or twenty minutes down the road when you've slinked in behind him. Keep in mind, though, that if the bad guy is also experienced, he's going to use all the tricks in the book to get to you first and make your TMA life a living hell in the process.

I am interested, though, in how you know what you're shooting at. By the time you are able to reliably classify your target, he should be close/loud enough for a BB tracker, and thus DEMON. I mean, that 50Hz-125Hz contact on your NB could be a fishing boat or a Kirov, and everything in between...

[Molon Labe]

I think a Kirov is a 50-195 :D

I should probably say something on topic too. If changing course across the LOS is not an option, I'd stay on a lag LOS and stick with course changes in the 30-60 degree range. Speed changes are also an option, but that might be every bit as obvious as a radical course change if you're trying to look like a fishing boat or yacht.

Something you have to accept is that the speed and quality of your solution depends on your willingness to change ownship's contribution to the bearing rate. And the more you change ownship's contribution, the more obvious it is that you're the enemy. It's a tradeoff. FWIW, IMO getting a solution more quickly is a higher priority than "looking innocent," since there are plenty of other tells than course changes. It is definitely possible that an opponent might mis-classify you, but I wouldn't count on it. Be ready to shoot.

[Molon Labe]

I'd like to add that the original premise about the solution-by-intersection didn't sit right with me. I took out the old pencil and paper and drew out a lead-to-lag and lag-to-lead just to make sure.

When you're on a lead LOS, there is no intersection; the lines are close to parallel. On an OverLead LOS (lead LOS but you have significantly more speed than the target), the lines will intersect beyond the target. On a Lag LOS, the lines intersect somewhere in front of the target. Changing from one to another doesn't necessarily generate an intersection, although if you go from lead to lag (or from lag to overlead), you will begin to get an intersection from the lag/overlead that you weren't getting before.

Is the target "near" those intersections? It depends entirely on the speed differential. The faster you are going relative to the target, the closer together the minimum possible range (intersection in lag) and maximum possible range (intersection in overlead) become.

So, I think it's better to think of the intersections as maximum or minimum possible ranges, and to guestimate how much closer/farther the target is based on whether you think the target is at patrol, tactical, or transit speeds, as well as your own speed.

[NFunky]

No, the intersection I'm talking about is when a target changes from a lead to lag or vice versa his speed across the LOS is temporarily 0 so the next bearing line I get after the maneuver will cross the last one at close to the range of the target. I'm not describing it very well, but I can't remember the title of the old thread that details it. I'll try to dig it up.

I guess this is a little more scenario specific than I thought. So for the record, the scenario I've been playing with is in deep water with no fishing traffic, only long transit cargo and oil and maybe a yacht or something now and then. I'm driving an LA and my enemy could be an Akula II, Han, Xia or Delta IV.

I'm pretty sure the fishing boat and power boat are the only neutrals with the 50, 125 hz lines so I can classify my enemy as hostile sub as soon as I can see two tonals. My targets are usually either pretty far away or pretty quiet so I generally don't get broadband until way after PROBSUB classification. The scenario is easy when up agaist the Han or Xia and still not that hard against the Delta, but I start having a real hard time when its the Akula. I'm pretty sure the Akula is quiet enough that he'll have me on sonar at about the same time I have him and that's why I've started thinking about not giving him a solution by changing LOS.

I feel a bit foolish for forgetting about speed changes as neither of us has DEMON, it would be impossible for him to tell whether it was speed or course that changed. My biggest problem has when I start off tracking him in a lead LOS. Everyone knows you should track and fire from a lag LOS, but the moment I switch, I'll be giving my range away. I have had some luck just staying in a closing lead until he changes LOS, but the AI doesn't seem to care that much about lead vs. lag and often he doesn't change LOS for the entire dive. I know I probably don't have to worry about the the AI using the bearing-lines-crossing-at-range trick, but I'd like to play as if I was fighting a human player so I'll be more prepared for when I finally feel ready to play online.

BTW, are there any other TMA tricks that I should know about? This one has been such an education and has forced me to rethink sub combat tactics quite a bit.

[Dr.Sid]

That is neat trick you can apply on newbies. I explain it like this:

You have crossed LOBs .. target can either be moving in same or opposite direction. If it is moving in same direction, LOB intersection is its maximal possible range. If it is going in opposite direction, intersection is its minimal possible range. If the target is not going either way (like when making a zig), the intersection is exact range.

Still it needs good name .. what about zig trap ? Gee .. I hope bubbleheads will come with something better :arrgh!:

[Molon Labe]

No, the intersection I'm talking about is when a target changes from a lead to lag or vice versa his speed across the LOS is temporarily 0 so the next bearing line I get after the maneuver will cross the last one at close to the range of the target .......... Everyone knows you should track and fire from a lag LOS, but the moment I switch, I'll be giving my range away.
Okay, that makes a lot more sense. I've actually never considered this before, so this is very interesting!

My take on what's going on is still a little different. It's not always the last bearing line before the switch that creates an intersection, when you've switched from lag to lead. Suppose during that time interval you stayed stationary in the LOS in the lead condition, producing parallel lines--no intersection. But if you go a few lines back to a position on your previous course, your net movement across the LOS will approach 0 or go negative for that interval and an intersection will be created somewhere beyond ownship. That's an overlead intersection--a maximum range.

So, I still see this in terms of the LOS switch creating a minimum and maximum possible range, it's just that the switch is being caused by a manuever in the other ship, but with the same result. The manuevering ship is putting itself at a bit of a disadvantage because it has less speed across the LOS over some interval, which tightens up the adversary's solution range.

I can think of two ways to try to mitigate this. First, if it's tactically feasible, approach the target from in front of or behind its course. This minimizes its speed across the LOS, so when yours drops off he doesn't have the speed to capitalize on it. The other way is to game the intervals. The closer you are in any interval to having no speed across the LOS, the tighter the solution range gets. So, try to be as far away from 0 during any 2-minute interval. That's not as complicated as it sounds, because it basically means driving your boat so that it's between your bearing lines on the even-numbered minutes.

Thanks for bringing this question up. TMA tactics just got a bit deeper and more interesting for me.

[goldorak]

In a contact dense environment use all the sensors, including periscope and esm. Try to do tma on surface contacts when you already have to care about possibile enemy subs is just overwhelming. Go to periscope depth and identifiy, classify and do tma on all visibile surface targets. For tma with periscope you only need 2 bearing lines + stadimenter information. It will be good enough. If there are esm signals merge them with the tma info. Idem for active sonar signals (although that could be bad news !!! :haha: ).

For sub contacts, if you're using the waterfall display then know this : if the trace of the contact is going away from your course : the contact is on a lag course (this is important because you don't have to do a course change just to find out). Viceversa if the trace of the contact is apporaching your course the contact is on a lead/overlead course (in this case you can't distinguish between the 2 and you must look at the bearing lines in the tma screen).

If the contact changes course you can see it on the waterfall display.
You will see what amounts to half an S, so if the contact was approaching your course before (lead/overlead) you'll see the trace go outwards (so lag), and viceversa. Comon wisedom has it that you can look at the bearing lines just before and just after the course change and have an estimate for the distance. Yes it will work, but without the other information (course) that won't do you any good. And sure as hell you'll get less information than what a previous tma could tell you.

Also if possibile always try tracking a contact on 2 sensors. Merge and triangulate 2 positions -> get precise tma without needing speed estimate and course change maneouvers.

Last but not least :

in a lag course the point of intersection of the bearing lines will always be the MINIMUM possibile distance of the target.
in an overlead (your going faster than him across the los) course the point of intersection of the bearing lines will always be MAXIMUM possibile distance of the target.


Depending on the situation you could always use active sonar.
Not as a primary ASW sensor, but from time to time it comes in handy.

[goldorak]

No, the intersection I'm talking about is when a target changes from a lead to lag or vice versa his speed across the LOS is temporarily 0 so the next bearing line I get after the maneuver will cross the last one at close to the range of the target. I'm not describing it very well, but I can't remember the title of the old thread that details it. I'll try to dig it up.


[cut]


I'm pretty sure the Akula is quiet enough that he'll have me on sonar at about the same time I have him and that's why I've started thinking about not giving him a solution by changing LOS.


You have to realise one thing : that a tma solution that is not updated is worthless. So if you change los because you must to get a fix on your enemy or to set a number of parameters (max distance, speed, course etc...) then not only you have to update your tma solution on him, but he has to update his solution on you as well. If he doesn't then his tma solution is going from good (if it was good to begin with) to bad to worse to worthless.

The golden egg so to speak is to learn how to keep the initiative.
That is to change frequently course and speed (at 2 minutes interval between the arrival of the bearing lines) so that your enemy has a hell of a time just trying to update his tma solution on you all the while you update easily your solution on him. And this is the real holy grail of manual tma. And it takes a lot of pratice. Because ultimately you will always have the initiative on your opponent, and his course changes and speed changes won't limit your ability to track him and constantly update your solution.

I don't know if the pdf is available on subguru, but its available on CADC website. Its called the red book and it contains a whole section that explains how not to lose (and update !!!) that precious manual tma you did while your quarry is changing course and speed. ^_^

[NFunky]

Looking at this situation further, it appears to be a 'whoever blinks first' kind of deal. I'd hazard to say that if both are tracking one another, but neither has a firm solution yet, the sub that takes the initiative by changing LOS will actually be at a disadvantage. His opponent will be able to get an immediate rough range while he will have to wait for his TA to stabilize and get another line or two before he gets one.

I wonder about changing course every two minutes. It would definately throw off an opponent's TMA, but would your own TA have time to stabilize and give you an accurate bearing line between turns?

[Molon Labe]

Looking at this situation further, it appears to be a 'whoever blinks first' kind of deal. I'd hazard to say that if both are tracking one another, but neither has a firm solution yet, the sub that takes the initiative by changing LOS will actually be at a disadvantage. His opponent will be able to get an immediate rough range while he will have to wait for his TA to stabilize and get another line or two before he gets one.


That's only going to be the case if he's beaming you. If he's headed toward or away from you an LOS switch is safe. But yeah, if he's beaming, it makes sense to make course changes without switching the LOS.

[Dr.Sid]

You can also change speed. That works same way. Doing very slow turns, like moving on circles, never straight is also good method for 1) improving your solution 2) worsening his solution, as all solutions expect the target to be moving straight. Leg can be spotted .. but slow gradual change in bearing rate can really puzzle the other guy.

[goldorak]

You can also change speed. That works same way. Doing very slow turns, like moving on circles, never straight is also good method for 1) improving your solution 2) worsening his solution, as all solutions expect the target to be moving straight. Leg can be spotted .. but slow gradual change in bearing rate can really puzzle the other guy.

Yeah but if the other guy already has a good solution on you, changeing slowly your speed will not degrade his solution rapidly enough to make it useless.

Really the point is that you're not going to to spend 40 minutes doing a tma. At most 10 minutes are necessary to get a good enough solution using the different methods we already talked about, solution that can then be refined all the while you send the torpedo on the target.
There has to be a moment when you say enough is enough, I've got the data for an attack. Otherwise you'll never have the intiative and without it you'll lose each and every time against a well skilled player.

Edit : also remember that taking evasive action and launching countermeasures right and left is akin to telling the enemy I'm RIGHT HERE. No tma is needed since the cm are static, they don't move so at most 2 bearing lines are necessary to triangulate their position and therefore YOUR position as well. Just something to keep in mind if you're a fan of the seawolf with its industrial grade capacity of cm.

[NFunky]

How do you guys balance making turns and such with stabilizing the TA? This has been by far my biggest issue in sub combat. I almost always retract my TA to about 1/3rd-1/2 and I still often get two bad bearing lines between turns. One line I could deal with, but two, especially when one of them is often only slightly distorted, really slows down my TMA. I find it a hell of a lot easier to do TMA on the Kilo simply because I never have to deal with TA stabilization.

[goldorak]

How do you guys balance making turns and such with stabilizing the TA? This has been by far my biggest issue in sub combat. I almost always retract my TA to about 1/3rd-1/2 and I still often get two bad bearing lines between turns. One line I could deal with, but two, especially when one of them is often only slightly distorted, really slows down my TMA. I find it a hell of a lot easier to do TMA on the Kilo simply because I never have to deal with TA stabilization.


Oh c'mon if you're using the sphere or hull array on the kilo what forbids you from using the sphere and hull arrays on the seawolf (together with the WAA) or the sphere array on the 688i ? In other terms your problem is really a non issue.

I already advised you to read the red book which is hosted on CADC website, lots of tactics are explained and most importantly you'll learn how to refine the tma without starting from zero every time your contact changes speed or course.

Look if you are tracking a sub only with the TA (and no other sensor) you'll need in the best case 3 or 4 bearing lines. Before starting tma look at your sonar and put yourself on a lag course (I told you about the track going left/right with respect to your course) and then wait 6 minutes for 2 bearing lines. That together with the bearing should give you a ROUGH idea what your enemy is doing. If he changes course/speed use the method described in the red book. If not just keep on waiting other bearing lines.

Another thing to keep in mind, you do not have to change course to start a new leg, you can increase or decrease speed. For instance the seawolf has a tactical speed of 15 knots if I'm not mistaken. That means you can start a leg at 7 knots (minimum speed to keep the TA in line with the sub) and then start the second leg at 12-15 knots. You'll get enough difference to nail down a probable good tma.
If you want to change course, wait for the new bearing line to arrive and then change course. Time it every 2 minutes (or multiple of 2 minutes), so you can change course every 4,6,8 minutes right after the new bearing line has been sent to the tma station.