Dive time in v1.3 screwy?

[Tobus]

WOW, that's one great test!

Screwy kind of physics the dev's have used on this one.

[FooFighters]

Wow.. this is really getting interesting..
Strange diving times devs

[kv29]

people here never cease to amaze me, flaws can´t hide anywhere
are the involved numbers tweakable?

[SteamWake]

It has been known for some time that if there is a short period of time between dives you will dive faster.

The assumptioin is that there is still 'water' in the ballast tanks so they dont have to 'fill' all the way.

The dive planes evidently are just eye candy. In the previous versions they dident even come down half the time and had no effect on dive times. Unfortunate but true.

The 'data' chart above is about what I expected to see.

You want to see some really diverse results throw a sugar boat into that data.

thanks for running the tests. It seems strange that the devs would consider such things as amount of residual water in/on boat when calculating dive times but then ignore the fact that the earth is spherical when doing travel distances (see the thread about fuel efficient routes)
http://www.subsim.com/radioroom/showthread.php?t=118877

[nomad_delta]

Originally Posted by SteamWake

It has been known for some time that if there is a short period of time between dives you will dive faster.

The assumptioin is that there is still 'water' in the ballast tanks so they dont have to 'fill' all the way..

I didn't, but I sure wish I'd known that before I started testing. It would have saved me a whole lot of time & banging my head against the wall trying to figure out what I was doing wrong when my numbers weren't making any sense at all.

It does make total sense, now, though. The devs even bothered to include the "water draining out of the sub" animation which lasts exactly as long as the effect on dive times dos, and the dive times even change gradually as the water drains out. I think that's pretty awesome.

Does anyone know if there is a 'more correct' term to describe the ballast tanks being full of water or not than what I've used above? I didn't know what to call it.

Originally Posted by SteamWake

The dive planes evidently are just eye candy. In the previous versions they dident even come down half the time and had no effect on dive times. Unfortunate but true.

They're not quite just eye-candy, as they do seem to have an effect in some of the tests, just always the correct effect (as Tambor said, depending on the circumstances it can even be backwards) and not as much of an effect as I would think they should.

Originally Posted by SteamWake

The 'data' chart above is about what I expected to see.
You want to see some really diverse results throw a sugar boat into that data

I plan to, actually; Now that I've got my methodology down it shouldn't take quite so long to run the tests, and I'm hoping we'll have a clearer picture (for better or worse) once I've added the data for the other subs.

As soon as I'm done I'll put a a new chart with all the info.

nomad_delta

[nomad_delta]

Originally Posted by kv29

people here never cease to amaze me, flaws can´t hide anywhere
are the involved numbers tweakable?

As soon as I'm done testing, I'm going to find out. :p

nomad_delta

[JREX53]

Not all of the water is blown out of the ballast tanks when the sub first surfaces in RL. The subs I was on had a High Pressure blower to blow out the residual water in the ballast tanks. It does take about 20 minutes in RL to get all of the water out of the tanks. So this might have been factored into the game, but I don't know for sure.


edit: That should have said a "Low" Pressure blower, not "High" Pressure Blower.

[SteamWake]

Originally Posted by JREX53

Not all of the water is blown out of the ballast tanks when the sub first surfaces in RL. The subs I was on had a High Pressure blower to blow out the residual water in the ballast tanks. It does take about 20 minutes in RL to get all of the water out of the tanks. So this might have been factored into the game, but I don't know for sure.

Well keep in mind were talking about real life physics vs a computer 'model'.

My guess is that somewhere there is a set of values for the ballast tanks for the sake of example lets say 0 = empty 100 = full.

When you broach the surface they are probably somewhere around 60 and decreases over time to emulate 'draining'.

Just a guess.

[JREX53]

Originally Posted by SteamWake

Well keep in mind were talking about real life physics vs a computer 'model'.

My guess is that somewhere there is a set of values for the ballast tanks for the sake of example lets say 0 = empty 100 = full.

When you broach the surface they are probably somewhere around 60 and decreases over time to emulate 'draining'.

Just a guess.

Isn't that what I said. I know we are talking about a Computer 'model' not real life.

[-Pv-]

"...every time hit the dive key blow crush depth it'll rise to crush depth..."

Try diving from deck awash (22ft at the keel and diesels still running) and you'll have the supports under water in about 15 seconds. This is the profile I use for all my surface attacks as well as defending against aircraft.
-Pv-

[Canonicus]

Originally Posted by Steeltrap

I've posted a number of times on this subject of dive behaviour. I even went so far as to test time taken to dive/rise in 50' brackets from surface to 250' and back at various speeds, from ahead 1/3 to flank.

My conclusion was this:

The dive times are hardcoded. You take x seconds to go from 50 to 100, y from 100 to 150 etc. Those times remain unaffected by your forward speed, which is totally unrealistic. The dive angle is also purely 'visual' in effect. At slow speed this is apparent as you travel more quickly vertically than horizontally, while the reverse should always be true unless you are using excessive blowing/pumping. Look at your stern planes and then look at the pitch of the sub - the two are unrelated. Changing depth once already submerged involves your stern remaining near horizontal with the stern planes on full dive/rise.

Just another 'realism' thing that's out the window.....

Well....They aren't....You can change the rate at which the ballast tanks fill-up by changing a value in the DATA/SUBMARINE/NSS_*/NSS_*.sim file using the Minitweaker app. Category 4 is called flooding.

You'll see this...

ManBT_flood_speed = 20000 ( or a similar number)

Changing the number to read, lets say, 35000, will cause the tanks to flood faster and consequently give you faster dive times.

For example...

- ManBT_flood_speed on Tambor/gar/gato from 20,000 to 35,000
(crash dive speed increases from 1min 10 seconds to 46 seconds)

- ManBT_flood_speed on Salmon/Sargo from 20,000 to 29,000
(crash dive speed now in the 45-48 second range)

Another file to look at is called...

DATA/SUBMARINE/NSS_*/NSS_*.zon
------------------------------
Adjust the crash speed value from 2 to 1.


If you don't know how to use the MiniTweaker app...then use Ducimus's Trigger Maru 1.3 mod, which has these adjustments already made for you.

Cheers

[Rockin Robbins]

How are you measuring dive times? In RL dive times were from the order to dive until periscope depth was reached. Less that 60 seconds was the goal.

40 to 48 seconds would be unrealistically fast.

[Steeltrap]

Hi Canonicus.

I'm not trying to make the boat dive more quickly. I was - and perhaps didn't explain it well - making the point that your dive times from one depth to another (be it surfaced to 50', or 50-100, 150-200 etc...) seem to be fixed, irrespective of forward motion. This is most definitely an 'error' as subs of those times were particularly reliant on forward motion for depth changes, in combination to minor pumping/blowing of trim tanks.

I tested this at 1/3, 2/3, standard, full and flank speeds. What I found was that the times taken to change depths were almost identical at ANY speeds (although not the same for different brackets).

In other words, if it took 20 seconds to go from 100' to 150' at 1/3 speed, it took almost exactly the same amount of time to do this at flank. When I said 'hard-coded' I meant that these times for changes in depths seem to be fixed. I should have chosen another term. Interestingly, it took longer to change depth by 50' when you were deeper than at shallower depths, even if you weren't coming from the surface. It also tended to take longer coming UP compared with going DOWN.

One question: does changing those flood rates have any effect on depth change rates once you are already dived? i.e. does it only affect rate of diving from surfaced state? What about from 150'-200' if you've been at 150' fro 30 minutes?

Either way, it seems to me that the current situation of being able to change depths at the same rate at any speed is clearly unrealistic/flawed.


Cheers

[tater]

Originally Posted by Rockin Robbins

How are you measuring dive times? In RL dive times were from the order to dive until periscope depth was reached. Less that 60 seconds was the goal.

40 to 48 seconds would be unrealistically fast.

From what I've read 30-35 seconds was the goal. 60 was a prewar standard time. Silent Running talks about drilling the crew for 30-35 second crash dives and specifically states that slower than that is dangerous. Similar in other books I've read.

tater