Bearing Rates and the Nav Map

[SeaQueen]

Hey Guys!

I think I've finally figured out how to make use of the bearing rate indicator on the nav screen for targets.

In order to do better TMA, I've started keeping a manual bearing rate. My spread sheet calculates it automatically, I just have to put in times and bearings. It just does a quick least squares fit to a line. I read the correct coefficient, and that's the best estimate of my bearing rate.

The thing is...

When my firing solution is really close to where my target is, the bearing rate I calculate by hand, equals the bearing rate calculated by DW on the nav map. So... I can use that to have a pretty good estimate of how well I'm doing on the TMA screen. There's actually a geometrical reason for this, because I think I understand how DW calculates the bearing rate it displays. It's just the target's relative speed across the bearing divided by his range, according to what you put in as your firing solution.

For those not up to curve fitting, it's probably sufficient to just take a ruler and some graph paper, plot time v. bearing, and read the slope of the line.

[Henson]

There is a formula in there, and it's very fundamental to TMA.

What if it wasn't bearing rate you were trying to figure out, but was something else, like....range?

This is the first thing they taught me in the TMA part of my school. It's the inverse relationship between bearing rate and range, and understanding everything else hinges on this.

When you combine ekelund ranging or tri-ranging with this formula and a best estimate of speed, you will know speed across the line of sight and course. Who needs a fire control system when you can look at the sonar display and do it all in your head?

[Dr.Sid]

Well you need good solution if the target is far away. You need great solution if your torpedo is not auto guided (WW2 torpedoes).
But in DW .. if it is far, it will detect the launch and evade. If it's near, just send the fish down the actual bearing. All you need is general distance estimate.
With DW there is problem in dense situation. Solutions gets old. You can have solution at 90, when sonar says track is 270 !. This will degrade shooting much more then bad speed estimate or distance estimate. You can of course hop to TMA and build solution manually.
But sometimes it works best with no TMA at all.

Hm .. with sub launched asroc, THEN you need quite a solution. But I had no chance to use these for a time. You need deep water, and far submerged contact. Submerged contacts have this problem that you usually detect them way too close

[SeaQueen]

Originally Posted by Henson

There is a formula in there, and it's very fundamental to TMA.

What if it wasn't bearing rate you were trying to figure out, but was something else, like....range?

Then you just divide the estimate of speed across the bearing by the bearing rate. Anyone who knows highschool geometry can figure it out. It's really just a fundamental fact of living in Euclidean space. :-)

It's interesting, though, because unless (in the game) you have DEMON, you have to make an assumption about the target speed, and whether you're on a lag or overlead LOS. I'm not sure if that influences the likelihood of making a hit, though, since the torpedoes have an absurdly high search rate.

[SeaQueen]

Originally Posted by Dr.Sid

Well you need good solution if the target is far away.

That's why I'm spending this much thought on it. I want be able to hit things pretty consistently at long ranges. Close in is not fun, counterfire starts to get a little too effective for my tastes. If given a choice, I'll hit 'em from a long way away. It makes me less detectable. It makes their counterfire less effective. All in all, it's mo'betta.

But in DW .. if it is far, it will detect the launch and evade.

Isn't there something about if you launch below a certain depth there's no TIW call?

If it's near, just send the fish down the actual bearing. All you need is general distance estimate.

That's what the bearing rate will give you, and a pretty good one too.

Hm .. with sub launched asroc, THEN you need quite a solution. But I had no chance to use these for a time. You need deep water, and far submerged contact. Submerged contacts have this problem that you usually detect them way too close

It depends. I've noticed that in DW detection ranges depend a lot on what depth everyone is at, and not just because of the layer. That's why in my scenarios, I try to have target's depth chosen randomly from 2 or 3 different options.

[micky1up]

the simulation is at fault here a tma crew should by even mediocre standards produce a valid range co and speed in about 5 mins also a real sound room crew can tell you if a contact is close or far and what it actually sounds like mv warship or fishing vessel and an average TPK speed for the contact this also refines the tma effort its just not represented very well in the game

[Dr.Sid]

Originally Posted by micky1up

the simulation is at fault here a tma crew should by even mediocre standards produce a valid range co and speed in about 5 mins also a real sound room crew can tell you if a contact is close or far and what it actually sounds like mv warship or fishing vessel and an average TPK speed for the contact this also refines the tma effort its just not represented very well in the game

Oh yes .. also priority for TMA would help a lot. I don't need to track 10 friendly warships 50nm away, if there are two enemy subs near and I need acurate and actual solution NOW.
Maybe if I jump to TMA and if I select contact, autocrew will update it right away. Does anybody know how exactly it works ?

[micky1up]

Originally Posted by Dr.Sid

Oh yes .. also priority for TMA would help a lot. I don't need to track 10 friendly warships 50nm away, if there are two enemy subs near and I need acurate and actual solution NOW.
Maybe if I jump to TMA and if I select contact, autocrew will update it right away. Does anybody know how exactly it works ?

thats how its done in the real world my friend i have two operators with me on the TDHS tactical data handling system one duz the big picture and what we call housekeeping ( making sure the info coming in from sonar is correct) and the other works on the contacts of interest that i and the oow designate

[Henson]

Originally Posted by micky1up

thats how its done in the real world my friend i have two operators with me on the TDHS tactical data handling system one duz the big picture and what we call housekeeping ( making sure the info coming in from sonar is correct) and the other works on the contacts of interest that i and the oow designate

This is true. We track EVERYBODY. Driving underneath fishing trawlers can be very bad. So can deep draft merchants. Warships are a counterdetection threat, and being detected by friendly warships is just as bad for us...if we're in a war, who's to say they don't get nervous and pop us one just because we're a submarine? We also need to be ready to come to PD at any time, and the game does not model that well at all: coming to PD is a Big Deal, and in high contact density can be a time consuming evolution for us to do safely.

Once you have a good solution on a contact you can pretty much leave it alone, and just reevaluate it every time something changes. There is always a little bit of error, but over time it becomes negligible. I've stood watches where I tracked two contacts the entire time, and then I've been in situations where there were hundreds and the OOD got me some help. Regardless of the situation, everyone initially goes into that system with an updated solution.