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Old 03-21-2019, 04:22 AM   #1
Gummi
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Default Blowing negativ tank loud?

Hi. The laterst game im joining The mayority is using negativ tank when diving from surface to periscope deaph. This is not an emergency dive, just normal operation.

My point is that blowing that negativ tank submerge must be a strange och and load sound for any destroyers listen out there. So i prefer speed and dive planes only. But then crew yell att me to use negativ tank.
if its a crashdive I use it. But then we allready spotted so more sounds doesnt matter

My Question is.
does destroyers pick up sounds then you blow negativ tank
why use negativ tank IF you not spotted, only consume compress air
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Old 03-21-2019, 06:14 AM   #2
Cyborg322
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Assuming the negative tank is empty you dont need to flood it just use dive planes and main ballast when you start a mission the negative tank is flooded it could be that if I understand your point
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Old 03-21-2019, 07:04 AM   #3
Gummi
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NO.. All The time during mission.. When cruising at surface The tank is full and after depth achive they blow it to maintain depth, then after surfande they fill negativ tank again and so on..

I want too keep it emty at surface, and only fill it when we crashdive.
but allmost every crew i join tell me when im dive officer i must fill negativ tank before we go to periscope depth,
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Old 03-21-2019, 07:23 AM   #4
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I would do it your way it makes it easier to get to scope depth unless there is an emergency not sure if noise is an issue blowing ballast this is a great video worth watching https://www.twitch.tv/videos/396680215
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Old 03-21-2019, 10:00 AM   #5
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Caveat: I don't have the game yet. So I haven't tried this in practice yet.

I think it is proper to keep the negative tank filled when on the surface, and as such I think the default state of the tank is warranted. As far as I learned from comments here and in the discord channels the boat has positive buoyancy when the negative is filled and the ballast tanks are empty. So you can stay surfaced, or slowly rise, with the negative tank filled and the ballast tanks emptied and neutral dive-planes.

When somebody calls out the alarm to crash-dive you don't want to wait until the negative tank is filled. You don't have the time. You want as little positive buoyancy as possible at that point. So it is better to have it filled as a precaution and you only need to flood the ballast tanks to go down quickly.

When ever you are submerged you can empty the negative at an appropriate dept to arrest your dive rate and limit the air pressure use to empty the negative tank. If you want to go deep quickly you can keep the negative tank filled longer, but that will have consequences as to how much air pressure that requires to empty at deeper depth. It's a choice. I don't know if you can arrest the dive with filled ballast and negative tanks on dive-planes and speed alone. Either way, sooner or later you want to go slow, so the negative tank needs to be emptied to be neutrally buoyant.

In or after non-crash dive situations the enemy warships are less likely to be near the boat. So I don't think emptying the negative tank making noise is going to alert anyone. Maybe emptying it slowly produces less noise and you can avoid detection if it does make you detectable. As I said, I have no gameplay experience to substantiate that yet.
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Old 03-21-2019, 11:20 AM   #6
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Been testing different ways. Doing it by the book as you describe seems the best method its also in the guide that way. Also experimented with blowing main ballast too you can get away with only blowing a small amount out to stay surfaced but I would not recommend it
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Old 03-21-2019, 12:15 PM   #7
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Be aware that flooded ballast tanks reduce your speed a lot.

Don't know how much speed the negative ballast tank take from you. The main ballast tanks slow you down at surface.

Been playing with people that seems to know what they were doing and those Captains always used the negative ballast tank empty, and only flooded it when in crash dive (by the way, the negative ballast tank get flooded VERY quickly. Not like their big brothers )
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Old 03-21-2019, 01:29 PM   #8
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Did some testing now when I got home to computer for some testing.
Speed Testing: All testing was in Full speed diesel engine:
  • Negative tank Empty, F/A Ballast tank Empty: 18,0kn
  • Negative tank Full, F/A Ballast tank Empty: 17,8Kn
  • Negative tank Empty, F/A Ballast tank Full/Empty: 15,25Kn
  • Negative tank Empty, F/A Ballast tank Full/Full: 12,95Kn

Next test I did what time it took to dive with different settings. time started at switching to electric engiene, diveplane preset down
Workorder:
  • Diesel Full speed / Electric full speed / Open Negative / Open Ballast
    13m -44s / 30m -54s / 50m -75s
  • Diesel Full speed / Electric full speed / Closing Negative (full at start) / Open Ballast
    13m -44s / 30m -54s / 50m -75s
  • Diesel Full speed / Electric full speed / Toutching Negative (emty at start) / Open Ballast
    13m -114s / 30m -130s / 50m -173s
*Edit want to test with ballast fully filled
Diveplane at Zero now, and Ballast full (off course this is the fastest way to dive, if maxspeed isnt an issue)
  • Diesel Full speed / Electric full speed / Diveplane 0->-35 / Negative emty
    13m -46s / 30m -71s / 50m -81s
  • Diesel Full speed / Electric full speed / Open Negative / Diveplane 0->-35
    13m -18s / 30m -35s / 50m -55s

So, If you have negative tank allways open, you loose 0,2Kn att FS, Don´t gain anything when diving. because its fills up faster then ballast tanks
If you don´t fill negative when diving you loose 70s to dive to 13m, but you get more controlled diving

I did it solo so take time as "isch", so if you full crew maybe can do it faster.

Last edited by Gummi; 03-21-2019 at 03:36 PM.
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Old 03-22-2019, 10:05 AM   #9
Pisces
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Quote:
Originally Posted by Gummi View Post
Did some testing now when I got home to computer for some testing.
Speed Testing: All testing was in Full speed diesel engine:
  • ...
  • Negative tank Empty, F/A Ballast tank Full/Empty: 15,25Kn
  • Negative tank Empty, F/A Ballast tank Full/Full: 12,95Kn
I don't quite understand what ballast tank is empty and what is full in these situations. In these lines, is the forward tank always full and the aft ballast tank empty and then full? Or in what other arrangement am I supposed to understand "Full/Empty".

Quote:
Next test I did what time it took to dive with different settings. time started at switching to electric engiene, diveplane preset down
Workorder:
  • ...
  • Diesel Full speed / Electric full speed / Toutching Negative (emty at start) / Open Ballast
    13m -114s / 30m -130s / 50m -173s
...
What do you mean with "toutching"? Almost empty negative tank?

p.s. Played the game for the first time yesterday. Focusing mostly on depth control and helm while somebody ([CBS]_King or something like that) was on the TDC/AP attacking convoy elements . It was hard to maintain depth while diverting attention to other tasks. But that is why it is supposed to be teamplay. As such I don't have feel yet for how strong the effect of the negative tank is. You can easily undershoot periscope depth. But empty negative tank clearly takes longer. And when blowing negative tank too early you may not submerge at all any time soon. Anyway, so far the learning curve for this small fish in the bilge water.
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Old 03-22-2019, 10:26 AM   #10
Gummi
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Quote:
Originally Posted by Pisces View Post
I don't quite understand what ballast tank is empty and what is full in these situations. In these lines, is the forward tank always full and the aft ballast tank empty and then full?
F/A - Fore and aft tank,
The Fore tank is full with water, you get 15.25Kn
And if you fill both F/A with water you only get 12.95Kn

The good thing to fill both F/A tank is quicker dive, and (dont know if game calculate it) lower silhouette because only tower is above water

Quote:
Originally Posted by Pisces View Post
What do you mean with "toutching"? Almost empty negative tank?
That was just to get the traveltime for me at same at other test, just get to station. clickt it and then walk to the other.
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Old 03-22-2019, 10:31 AM   #11
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Ok, that's clear to me.
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