Solid line at Own Ship stern instead of course?

[ewjax]

Hi,

Back when I was pushing subs around the North Atlantic for a living, in the mid to late 80's, the waterfall sonar display (on the conn at least) for the BQR-21 system had a solid line present at own-ship's COURSE, not the reciprocal of the course as is shown on the 688 and SSN-21 waterfall displays in the Dangerous Waters game.

Two questions:

1. Is that really how the 688 and SSN21 systems are configured? Or is that a mistake in the game? I never served on either class and haven't seen their systems.

2. If that is how they really are set up on the 688 and SSN21 systems, can I ask if anyone knows why that change was made? What's the advantage of having the line at the stern rather than the bow? I lived and died by that display, I could glance at it and pretty much instantly create a mental picture in my head of the contact situation. The biggest clue I could get from it was whether the contacts were drawing forward or aft ... "all on the left are drawing left, all on the right are drawing right, let's go to PD". I grant you can do the same thing with the stern line, but it's so ingrained in me to see that line and think "O/S Course" that it is REALLY confusing to un-think that. Plus it looks just like the CEP plot if the line is drawn for OS course, rather than OS stern.

If entire generations of officers like me were trained to think of that line as O/S course, there had to be a compelling reason to change it to O/S stern. Anyone know what that might be?

Of course, I had most of my training on the Mk114 F/C system, and really miss the PK (Position-Keep) display on the 117, 118, and newer systems...stacking dots is for wussies...perhaps I'm equally dinosauric with wanting that waterfall to have the line at OS head rather than stern....

[Bubblehead Nuke]

Welcome fellow bubblehead.

Remember, this is a SIM. One that is available to anyone in the world. There will be things that do not match up with reality or the way we remembered.

They do not want to give away all the tricks of the trade you know. Those of us who served on subs constantly bang our collective heads on 'this is not how we do things' button.

See my postings about cavitation.. and others who posted similar things about how things are done in the fleet.

[ewjax]

Heya! Yes, I read your post on cavitation and agree. Maneauvering isn't going to cavitate, regardless of the ordered bell, unless you explicitly tell them to. On the Lafayette-class boomers that was done via a little button the helmsman would push 3 times that would ring the bell in maneauvering 3 times, and via the 7MC, "Maneuvering, Conn, Cavitate". "Cavitate, Conn Maneuvering Aye".

And yes, it's a sim, but the passive broadband system and displays are remarkably similar to what I remember, with the exception of the Own-Ship Course vs Stern line I mention. That makes me think the fleet has changed, since the makers of the game went to such lengths to get the rest of that display right.

Do you have any experience in 688 or SSN21 such that you can confirm the presence of that stern line?

BTW, I played the Jane's "688" computer game before this, years ago, which this game is obviously drawn from, and I don't recall that waterfall having the stern line, I recall it having OS course.

[Dr.Sid]

If the line was at OS course it would collide with active area of sphere array. How was this solved on that sub you served on ?

[sonar732]

I remember hearing that the creators of Fast Attack got in trouble by the DoD for their sonar display being so clos to RL. Surely Sonalysts learned their lesson by that matter.

[ewjax]

If the line was at OS course it would collide with active area of sphere array.

Hrm....pardon? I don't understand.

[Dr.Sid]

Sphere array can 'hear' bearings from lets say -120 to 120 degrees. If you draw solid line at 0 it would be in the active area and it could mask contact at bearing 0.
If you draw solid line at bearing 180 there is no conflict.

[goldorak]

Sphere array can 'hear' bearings from lets say -120 to 120 degrees. If you draw solid line at 0 it would be in the active area and it could mask contact at bearing 0.
If you draw solid line at bearing 180 there is no conflict.


But isn't the priviledged method of detection the towed array ?
In this case its the stern line that would be in the active area of the sonar, so you're better off with the solid line at OS course.
Frankly I find it more intuitive that the solid line be the OS course instead of the 180 line.

[Smaragdadler]

...now I have a knot in my brain. :dead:

[Henson]

The SAPBB displays that I've seen at work always have stern markers, not course markers. I assume that this is because, as mentioned, a course marker would cover a part of the area being searched.

IIRC in-game the sphere has a stern marker, and the TA has a heading marker.

[ewjax]

Sphere array can 'hear' bearings from lets say -120 to 120 degrees. If you draw solid line at 0 it would be in the active area and it could mask contact at bearing 0.
If you draw solid line at bearing 180 there is no conflict.

Ah, I understand the question now. I was confused by the word "active", which I took to mean "active sonar".

Unless I'm wrong, as I recall we could turn that line on or off (and maybe even toggle it to OS stern, which I never did - in fact I spent a great deal of time in the game looking for the switch to flip it to OS course rather than stern before I posted). Maybe the sonar shack kept theirs off, but it was always displayed on the conn - it's pure gold for the OOD, and I miss it in the sim. The line looked very different from the contact traces, I'm guessing they really wouldn't obscure one another even if they were on top of one another - I can never recall thinking that was an issue.

Still waiting for a 688 OOD to confirm/deny the stern line. Henson, what system is the SAPBB? What class of ship?

[Henson]

Still waiting for a 688 OOD to confirm/deny the stern line. Henson, what system is the SAPBB? What class of ship?
'Q5, 'Q6, BSY1, and 'Q10-ARCI phase IV (I'm at a training command.) I'm an FT, not a STS, but I guess that actually means I spend more time looking at the ASVDU.

OODs refer to it as a "stern marker." I'll check at work tomorrow to make sure.