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.

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

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

[Molon Labe]

Originally Posted by 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 .......... 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.