Realism v simulation

[Bellman]

Indebted to Blackmuzzle over at Battlefront for the link to unofficial transcript of the USS Greenville incident.

An LA 688 SSN 72 - an officers answer throws some light on how far our sim. has traveled from reality.
The two issues are baffled areas and speed of ascent.

Baffles - ''Sonar baffles are about a hundred -- on this class of submarine was honard sonars about 120 degrees
in the stern sector centered either side of the stern of the ship relative, where you're acoustically deafened
because the sonar is not designed to look in that sector through ownership's machinery and hull noise.
So you turn your ship in the horizontal plane to uncover your previously baffled area.
and you generally turn at least 120 degrees so you now have that previously deafened sector under observation
by your passive sonar system. And you may have new contacts in that sector, and if so you start
to develop your first leg on this new course of information on those new contacts. ''

Why have we got a mere 60 deg. baffled area ?

Ascent - Source believed to be Admiral Griffiths - the sub was at 50 ft and 10 knots prior to going to
periscope depth (DW 63 ft) it took he said '' a minute or so .''
Now the 688 DW takes 2 min. 10 secs to do this - she will go from 150 ft to 83 ft in 53 secs and then takes a huge time to level off.

:lol: Could understand if this was periscope deployment and near surface related in order to avoid collision
with surface craft - the transcript reports use of the periscope prior to it breaking the surface to spot 'shadows' etc.
But this slow levelling off phenomena applies at all depth changes.

Quote from Marconi over at Battlefront ''Here're a few musings from a 688/637 class qualified Diving Officer of the Watch:''
''For The Bellman>>The depth change performance in DW isn't unrealistic, it's dreadful.
Take it from a guy with thousands of hours in the center seat. '' :ping:

Bellman.

'Never send to know for whom the bell tolls....'

[Rip]

Indebted to Blackmuzzle over at Battlefront for the link to unofficial transcript of the USS Greenville incident.

An LA 688 SSN 72 - an officers answer throws some light on how far our sim. has traveled from reality.
The two issues are baffled areas and speed of ascent.

Baffles - ''Sonar baffles are about a hundred -- on this class of submarine was honard sonars about 120 degrees
in the stern sector centered either side of the stern of the ship relative, where you're acoustically deafened
because the sonar is not designed to look in that sector through ownership's machinery and hull noise.
So you turn your ship in the horizontal plane to uncover your previously baffled area.
and you generally turn at least 120 degrees so you now have that previously deafened sector under observation
by your passive sonar system. And you may have new contacts in that sector, and if so you start
to develop your first leg on this new course of information on those new contacts. ''

Why have we got a mere 60 deg. baffled area ?

Ascent - Source believed to be Admiral Griffiths - the sub was at 50 ft and 10 knots prior to going to
periscope depth (DW 63 ft) it took he said '' a minute or so .''
Now the 688 DW takes 2 min. 10 secs to do this - she will go from 150 ft to 83 ft in 53 secs and then takes a huge time to level off.

:lol: Could understand if this was periscope deployment and near surface related in order to avoid collision
with surface craft - the transcript reports use of the periscope prior to it breaking the surface to spot 'shadows' etc.
But this slow levelling off phenomena applies at all depth changes.

Quote from Marconi over at Battlefront ''Here're a few musings from a 688/637 class qualified Diving Officer of the Watch:''
''For The Bellman>>The depth change performance in DW isn't unrealistic, it's dreadful.
Take it from a guy with thousands of hours in the center seat. '' :ping:

Bellman.

'Never send to know for whom the bell tolls....'

The baffle is less than 120 degrees. They always turn 120 to be safe. You would be suprised how much technical details these guys don't know. I mean crap they have to learn a massive amount of info from the time they join until they ever get to stand OOD.

The depth change data is fairly accurate. Anytime you are going to PD the OOD will constantly spin on the scope while looking for shadows. If one is seen Emergency Deep is ordered to avoid a collision. As soon as the scope breaks the surface the OOD will verbally call out so and make a low power sweep. Reporting any close contacts. Also for ship safety the ESM watch is closely monitoring his recievers for strong close contacts. These can also be picked up slightly below the surface. The EW reciever is the first thing to break the water. Any sign of unexpected close contacts is reson to go deep quick.

[Bellman]

:) Rip - ''The baffle is less than 120 degrees''

How much less ? - lot of room down to our DW 60 deg.

Rip -''The depth change data is fairly accurate''

Which data - Greenville trans. or mine from 688 DW ?

Marconi - ''The depth change performance in DW isn't unrealistic, it's dreadful.''

You arent telling me surely that the 688 in DW taking a minute to level out over 20 ft is accurate ?
When the transcript shows the 688 takes '' a minute or so '' to go from 150 ft to Peri. depth !
One assumes that means arrive at periscope deployment depth level and ready to deploy the peri.

I dont think there can be much room for lack of knowledge -
''You would be suprised how much technical details these guys don't know.''

:lol: If these areas are 'sensitive' then I can understand and appreciate the need to 'muddy the waters'
and also the need to inaccurately simulate. But I cant imagine that these are such areas of concern.

[OKO]

Ascent - Source believed to be Admiral Griffiths - the sub was at 50 ft and 10 knots prior to going to
periscope depth (DW 63 ft) it took he said '' a minute or so .''
Now the 688 DW takes 2 min. 10 secs to do this - she will go from 150 ft to 83 ft in 53 secs and then takes a huge time to level off.

:lol: Could understand if this was periscope deployment and near surface related in order to avoid collision
with surface craft - the transcript reports use of the periscope prior to it breaking the surface to spot 'shadows' etc.
But this slow levelling off phenomena applies at all depth changes.

Quote from Marconi over at Battlefront ''Here're a few musings from a 688/637 class qualified Diving Officer of the Watch:''
''For The Bellman>>The depth change performance in DW isn't unrealistic, it's dreadful.
Take it from a guy with thousands of hours in the center seat. '' :ping:

Bellman.

'Never send to know for whom the bell tolls....'

well, in fact, The Bellman, it's always the end of the depth change that is slow.

The time when the sub need to equalize the level.
my personnal procedure to PD is this one =>
I order 2/3 when i reach 30m (or 100ft) and always the radar depth (17m on KILO, 54 ft on 688i, 51 on seawolf, 19 on akula)
this way, I'm faster at PD and can use radio/ESM a bit earlier.
the ship will change automatically to 5 knts when close to surface if you ordered 2/3 UNDER the depth of ~ 100ft or 30m.

But the physical model, even if some 'details' could be commented, looks really nice to me.

I imagine stabilizing the level on this kind of heavy ship need some seconds, and the actual process and time of DW looks great to me
500ft to PD in less than 4 mn, 100 ft to PD in 2mn with a 688i if you order 54ft and 2/3

you want to reach the surface staying submerged ?
=> order radar depth and 2/3
you couldn't reach the desired depth faster, but you really can make it longer, so do NOT overcontrol

When doing some big depth change, the changing depth rate is really strong until the stabilization step
but if you change from 10 ft to 10 ft, you will have a very low rate, because the stabilization rate start from the order.

I really think this model is enought great to let it like this and concentrate on other things :yep:

[timmyg00]

:) Rip - ''The baffle is less than 120 degrees''

How much less ? - lot of room down to our DW 60 deg.

Rip -''The depth change data is fairly accurate''

Which data - Greenville trans. or mine from 688 DW ?

Marconi - ''The depth change performance in DW isn't unrealistic, it's dreadful.''

You arent telling me surely that the 688 in DW taking a minute to level out over 20 ft is accurate ?
When the transcript shows the 688 takes '' a minute or so '' to go from 150 ft to Peri. depth !
One assumes that means arrive at periscope deployment depth level and ready to deploy the peri.

I dont think there can be much room for lack of knowledge -
''You would be suprised how much technical details these guys don't know.''

:lol: If these areas are 'sensitive' then I can understand and appreciate the need to 'muddy the waters'
and also the need to inaccurately simulate. But I cant imagine that these are such areas of concern. I think the words "unofficial transcript" say a lot... but think about what the Greenville was doing when she struck that boat. She was doing an emergency blow demonstration. Now, I am assuming that there was a mistake made in the original quote when it was mentioned that "the sub was at 50 ft and 10 knots prior to going to periscope depth (DW 63 ft) it took he said 'a minute or so'" when it was later mentioned that "the transcript shows the 688 takes 'a minute or so' to go from 150 ft to Peri. depth !" A transit from 150 to the surface using emergency blow would be fast... less than a minute, especially if the boat was doing 10kts.

If the transit was not using emergency blow, but was using normal planes/speed to work up to PD from 150, that transit usually does take 2 minutes or so at 5 knots (dependent on the sea state, and the technique and experience of the entire ship control party), and would be expected to take less time at 10kt, but perhaps the diving officer was using conservative plane angles to so as not to broach the ship. Besides, I find it hard to believe that they were going to PD at 10 knots. That speed exceeds the safety limits for the masts.

As far as the quote from Marconi, Bill Nichols has been around here a long time and was, IIRC, a Chief of the Watch AND a DOOW, and I have never known him to complain vociferously about the ship control performance in SC or DW. If it's wildly inaccurate, he'd be the one I'd expect to hear pitching a fit (although, on second thought, I've never known Bill to pitch a fit either...).

Anyway, DW is not primarily a ship-control simulator, just as it's not a flight sim.

TG

[Bellman]

:) TG and OKO - Thanks to both of you.

:ping: TG, I am ex RAF, and have concentrated solely on flight sims for more years than I care. All shapes and sizes !

Hence forgive please my obsession with climb/dive, rates of turn , blind spots etc.

:lol: But no flight sim. ever captivated ( and sometimes frustrated ) me as much as 688 then SC/SCX now DW.
Its the large areas of uncertainty that can drive you mad.(slowly)

Now guys, just a little detail - neither of you has addressed my query about baffle size.
If anyone out there thinks this is sensitive please use Prof. Galbraith's phrase - '' I hear you '' ...and I will put to sea. ;)

[Kapitan]

its a good game good mix of simulation and arcade gaming its almost top notch but not quite there yet maybe if DWX came out them who knows

[Rip]

:) Rip - ''The baffle is less than 120 degrees''

How much less ? - lot of room down to our DW 60 deg.

Rip -''The depth change data is fairly accurate''

Which data - Greenville trans. or mine from 688 DW ?

Marconi - ''The depth change performance in DW isn't unrealistic, it's dreadful.''

You arent telling me surely that the 688 in DW taking a minute to level out over 20 ft is accurate ?
When the transcript shows the 688 takes '' a minute or so '' to go from 150 ft to Peri. depth !
One assumes that means arrive at periscope deployment depth level and ready to deploy the peri.

I dont think there can be much room for lack of knowledge -
''You would be suprised how much technical details these guys don't know.''

:lol: If these areas are 'sensitive' then I can understand and appreciate the need to 'muddy the waters'
and also the need to inaccurately simulate. But I cant imagine that these are such areas of concern.

The baffles are not cut and dry. You begin to get ownship noise interferance around 45 degrees either side. 30 degrees either side or 60 total is very difficult to hear anything. 15 either side is pretty much blind.

The PD times he used in the Greenville transcript is right if everything is going well and seas aren't bad. In rough seas it takes longer because you must be careful. Heavy seas tend to cause a suction on the deck and will suck you up if not careful. The old man gets VERY pissed when you broach the sail. 6 foot swells only leaves you with about 6 ft to work with. This number is also greatly affected by the quality of the dive team and how well the ship is trimmed. Often when in transit they don't have time to trim well before going up. However if you are on station and doing slow search the trim is probably bang on. Unless you get stuch with the Supply Officer for diving officer :rotfl:

On the technical details. They remember the stuff that is important to them doing there jobs. Orders are to clear baffles using 120 degrees, how much the baffles affect and how many degrees exactly isn't all that important. Most of the younger officers are having to memorize amazing amounts of stuff about the power plant and the weapons that are important. So it isn't that suprising when they don't know what platforms have a topsail radar for instance. That was my job and they knew I would tell them. Same thing with sonar details. There are 15 people who know the system inside and out on board. The officers know they can count on the NCOs to do their jobs and know such stuff.

Some of this stuff is not done accurately not only for security reason, but also play balance. IRL the skimmers would get sunk quick and the Helos and P3s would have MUCH harder times getting contact. Wouldn't be much fun for them to search the whole game and not find ****. The tactics are pretty much the same. Just less effective. When we used to do excersises with the Air units we would have to surface and turn on the lights so they could get a fix on us. Then we would try to loose them. Just having them search for us in an area always resulted in them not finding us :up:

[Bellman]

:D Magic Rip - thanks. :up:

:lol: I am not rising to the bait on turning on the lights. :huh: :-j

[Bellman]

:lol: Rushed off to breakfast - and choked on the toast with a couple of points. :oops: :o

Your point is valid that limiting the sonar performance of the FFG by increasing the baffle area would inhibit gameplay.
But as a sub driver I wonder what the impact of increasing the baffle size would be on subs only ? :hmm:
With kind thoughts to the sub v sub MP community. :arrgh!:

Another point is - should TIWs be received from bearings that lie within your baffles ? Realistic ? :hmm:

You report a realistic situation where baffle performance varies and is not 'cut and dry'

I have thoroughly tested the performance of the SW baffles and as you know they cut off cleanly at 60 deg.
Placing many ships at varying bearings demonstated this and also importantly the need to make at least your initial ,
(in game)turn a minimum of 60 degrees. Only with this will you pick-up all available tonals and maximise your ability to log
close-in high bearing rate of change platforms. ;)

[Rip]

:lol: Rushed off to breakfast - and choked on the toast with a couple of points. :oops: :o

Your point is valid that limiting the sonar performance of the FFG by increasing the baffle area would inhibit gameplay.
But as a sub driver I wonder what the impact of increasing the baffle size would be on subs only ? :hmm:
With kind thoughts to the sub v sub MP community. :arrgh!:

Another point is - should TIWs be received from bearings that lie within your baffles ? Realistic ? :hmm:

You report a realistic situation where baffle performance varies and is not 'cut and dry'

I have thoroughly tested the performance of the SW baffles and as you know they cut off cleanly at 60 deg.
Placing many ships at varying bearings demonstated this and also importantly the need to make at least your initial ,
(in game)turn a minimum of 60 degrees. Only with this will you pick-up all available tonals and maximise your ability to log
close-in high bearing rate of change platforms. ;)

The TIW depends. I the TA is out you may detect threat tonals on it, or if it goes active you will pick it up on active intercept which is 360 degrees. IRL the edge of the baffles is not a black hole. It is a slope of decreasing SNR, albeit a fairly steep slope :yep:

Active intercept is another area which is only loosly simulated just like ESM/Radio. IRL you can perform very effective platform ID from intercepts. On the other side of things the TA performs much better during turns than real life. IRL TA bearings are disregarded typically until the array stabilizes after a turn.

[XabbaRus]

I have found that auto TA guy does seem to wait until TA has stabilised until the TA starts picking up again.

[Rip]

I have found that auto TA guy does seem to wait until TA has stabilised until the TA starts picking up again.

Strange. When I do slow turns I still get bearings while the TA is still turning. Is it just me?

[Amizaur]

When we are talking about sonar performance vs the angle, I have somewhat related question: I'm very curious if the TA is equally sensitive in all directions ? I would think that no, it's most sensitive in direction perpendicular to the line (so to the sides), but wonder how big is the difference ? And what with targets directly behind, with TW pointing at them - would they be detected ? And if yes, then with the same sensivity as targets on the sides, or maybe much lower ? Is TW coverage nearly 360deg (without ownship sector) like in SC/DW or is it best to the sides, medicore on other angles and worse at 180deg (behind) ? So to listen to given direction in real life would be the boat positioned 90deg off to have best possible performance from TA ?

[Bellman]

Amizaur wrote:-
'' So to listen to given direction in real life would be the boat positioned 90deg off to have best possible performance from TA ?''
....and beaming for TMA .

First it seems that the bafffles in real-life are greater than 60 deg but less than 120 deg.**

I would have expected three things also:-
1. That the SA baffle was greater than in-game.
2. That the TA performance would deteriorate substantialy around the
60 - 30 and 300 - 330 areeas.
3. That the TA performance would be severely inhibited around say 160 - 220.

** I refer again to the 'transcript' which would seem realistic:-
'' Sonar baffles are about a hundred -- on this class of submarine was honard sonars about 120 degrees
in the stern sector centered either side of the stern of the ship relative, where you're acoustically deafened
because the sonar is not designed to look in that sector through ownership's machinery and hull noise.

Final point - Take a distant TIW (too long in DW) but in the real world during run-out pre activation pinging
the torps tonals must be picked up either through Sph or TA and if the relevant bearing lies within the
baffle no such warning could be received.

'Clearing the baffles' was always an urgent priority in past sub sims
a vital self- defence precaution but DW/SC we have a very limited requirement for this proceedure.

[Bellman]

:lol: I remember an early Heli sim where you were engaging the enamy and had plenty to do
when 'Bitching Betty' would pipe up with the warning 'Behind you' :roll:

It concentrated the mind ! :arrgh!:

[Rip]

Keeping in mind that I was not a sonarman so my knowledge on the subject should not be considered definative. As I recall the TA sensitivity was not especially better on the beams but bearing accuracy was. There is a small null zone directly foward and aft of the array but it is very small. Performance in the forward section is also hindered substantially by own ship noise.

[Amizaur]

Hmm ok, so there is same number of hydrophones not depending on the angle, and same sensivity, but in areas along the line of TW the base is very short and time of sound arrival changes very little with bearing so bearing resolution is poor... makes sense. But even on the beams, is bearing resolution so good as in DW ? It's working on low frequency after all.... in DW the bearing you get is just exact, even with very weak LF contacts...
How big would be this very small null zone of TA, 5 deg or something ?

[Rip]

Hmm ok, so there is same number of hydrophones not depending on the angle, and same sensivity, but in areas along the line of TW the base is very short and time of sound arrival changes very little with bearing so bearing resolution is poor... makes sense. But even on the beams, is bearing resolution so good as in DW ? It's working on low frequency after all.... in DW the bearing you get is just exact, even with very weak LF contacts...
How big would be this very small null zone of TA, 5 deg or something ?

We should also keep in mind my experience is 20 years ago. The accuracy would as you imagine vary depending on signal strength. Whether the operator is keeping a good eye. There is always a little slop but an error of more than a degree would be unusual. Assuming the array is straight and stabilized. 5 degrees sounds about right 10 at the most. Ownship noise makes the forward 20 degrees or so difficult to make contact in. As I recall the bearing error would be more apparent as you neared wash out speed.

I would imagine at some point if they haven't done it already they will be able to get quality input even at maximum speed.