View Full Version : Steeper dive angle in the control room please
oscar19681
10-21-09, 05:02 PM
Can we please have some dive angles in sh-5 that are beyond 5 to 10 degrees please? In sh-3/4 the dive angles just seemed way to shallow if you ask me. I mean just look at this dive angle. the sh-3 dive angle isent even close
http://www.uboatarchive.net/U-604Binn27.jpg
Platapus
10-21-09, 07:10 PM
Just tilt your head when you dive. :D
Webster
10-21-09, 07:27 PM
only in crash dive or emergency surface would a sub be at such a steep angle
oscar19681
10-22-09, 06:40 AM
only in crash dive or emergency surface would a sub be at such a steep angle
Yes i,m aware of that but i dont see these angles in sh-3 or sh-4 in crash dive or emergency surface
only in crash dive or emergency surface would a sub be at such a steep angle
What kind of angles are you thinking of?
If a uboat managed 40° it's bow would be more than half way down to crash dive depth before the stern had gone underwater!
At 25° the sub only has to travel 6 times it's own length before it reaches crush depth.
A undamaged uboat doesn't have a very steep dive angle.
Sailor Steve
10-22-09, 11:59 AM
only in crash dive or emergency surface would a sub be at such a steep angle
Or in a faked picture.
"Hey, guys. Lean way over and I'll tilt the camera!"
On the other hand it's interesting that the bow planes are apparently at full down while the stern planes are almost flat.
BlueFlames
10-22-09, 12:25 PM
On the other hand it's interesting that the bow planes are apparently at full down while the stern planes are almost flat.
Damaged/malfunctioning boat out of control, perhaps? Might be time to tell the DC team to be more aggressive.
Ducimus
10-22-09, 01:34 PM
Old PR Kreigsmarine photo. I recall reading somewhere, that that photo is staged. Heck, Nazi Germany's PR ministry made several full length PR fillms, let alone still photo's. You'll find PR photo's on both sides of the war, some of them are rather amusing. I particuarlly like the ones on the US side. I think one is on the book cover of Silent Running. Nice crisp uniforms, they tilt their hats back and up their collars to try and look like they've been busy. Officer at the periscope wearing a Tie. :haha:
Randomizer
10-22-09, 02:46 PM
Or in a faked picture.
"Hey, guys. Lean way over and I'll tilt the camera!"
On the other hand it's interesting that the bow planes are apparently at full down while the stern planes are almost flat.
The pic may or may not be posed but thinking about it for a second and the zero angle on the aft planes makes perfect sense for the initial stage of the dive.
With both sets of planes at hard-dive the boat should tend to pitch down rotating around the centre of gravity (or perhaps the center of pressure which one would think would start forward and move aft to the CG as the boat achieves equilibrium in the dive.*) This might well cause the entire stern to come out of the sea and result in losing control of the rudders, aft planes and now free-spinning props. Good arguments to avoid big angles.
On the other hand with aft planes at or near zero, they should become the pivot point and so the props and control surfaces stay safely submerged.
If you can get hold of Submarine Commander by Paul Schraatz, he goes into great detail about the problems and pitfalls associated with big-angle dives in diesel boats.
<*My background is in ballistics not hydrodynamics so this is a guess and anybody familier with pitch behaviour of vessels in water may freely debunk as necessary.>
Sailor Steve
10-22-09, 02:59 PM
Good points, and I wasn't actually suggesting that it was posed - just that it was one of many possibilities.
What kind of angles are you thinking of?
If a uboat managed 40° it's bow would be more than half way down to crash dive depth before the stern had gone underwater!
At 25° the sub only has to travel 6 times it's own length before it reaches crush depth.
A undamaged uboat doesn't have a very steep dive angle.
From what I've read in Buchheim's Das Boot, the dive angles were definitely steep, especially with 'all men forwaaaard!'.
This from U-boatarchive seems sensible to me;
"(iii) Diving Angles.
During a normal crash dive, the angle tower increases from roughly 2 at the commencement to 10° as the bridge screen dips. Thereafter the angle down is normally from 12-15°, though angles up to 45 have been reported, after complete submersion."
http://www.uboatarchive.net/KTBNotesDivingCumulativeEdition.htm
Well, here is a scale diagram of a 45deg. dive:
http://www.b3tards.com/u/57a418c694bc7c6296b3/viicdive.gif
I haven't any facts of figures, but it looks far too dramatic to me.
At no point does the boat have any chance of a constant dive rate
and that's going right down to the absolute maximum depth.
The klauen would have the be utterly nuts.
That animation is kinda funny lol...
But I don't understand your point, you saying a boat diving at 45 degrees will reach 220 meters in 6 seconds? :doh:
edit: btw you sure that boat animation is at 45 degrees? Looks a little steeper to me.
I presume a submarine must gain speed in steep dive, just like an aircraft gains airspeed in this way.
Gravity is slightly reduced in water, but not by all that by much.
Is this modelled in SH3/4? I have never thought to really monitor My boats submerged speed while diving or accending.
Does the boat accellerate and still continue at a higher than normal speed after levelling off (having gained momentum), then gradually reduce speed down to whatever RPMs your electrics are driving?
IN SH3/4 I never noticed the effects of gravity or physics simulated in thii way, but then I was never looking for it.....
Then again, maybe my theroy is wrong? :haha:
Webster
10-23-09, 02:51 PM
I presume a submarine must gain speed in steep dive, just like an aircraft gains airspeed in this way.
Gravity is slightly reduced in water, but not by all that by much.
Is this modelled in SH3/4? I have never thought to really monitor My boats submerged speed while diving or accending.
Does the boat accellerate and still continue at a higher than normal speed after levelling off (having gained momentum), then gradually reduce speed down to whatever RPMs your electrics are driving?
IN SH3/4 I never noticed the effects of gravity or physics simulated in thii way, but then I was never looking for it.....
Then again, maybe my theroy is wrong? :haha:
not really, in a dive its a momentum (or inertia) vs resistance thing which follows the same patterns as aircraft but they are different. the effects of gravity are much less effective on submerged objects containing an air pocket because the floatation cancels out gravity to a large extent. if anything IMO the opposite is true, it would lose speed in a dive due to the increased resistance forces against it trying to push against the forces of resistance, floatation, and pressure changes.
a boat never really levels off, it has a bowl like action as it bottoms out its dive but bouyancy is all part of it too because the dive planes putting force against that bouyancy is what gives you the control or you would forever be in flux going up or down constantly
That animation is kinda funny lol...
But I don't understand your point, you saying a boat diving at 45 degrees will reach 220 meters in 6 seconds? :doh:
edit: btw you sure that boat animation is at 45 degrees? Looks a little steeper to me.
Yes, it is precisely 45 degrees at the steepest point.
It's not about the speed. Even slowed down to the correct speed, the
dive still looks utterly crazy.
I only have it going fast because no one wants to watch a .gif for 10 mins.
As soon as the boat reaches 45deg. it needs to pull up at an
impossible rate or it would go straight down to crush depth.
I presume a submarine must gain speed in steep dive, just like an aircraft gains airspeed in this way.
No, gravity does not give a uboat much speed at all because the u-boat
never has much weight.
Even with all tanks flooded it will only weigh about 10 tonnes.
It might get a knot or three of extra speed on the way up because the
VIIC can have a positive buoyancy of exactly 102 tonnes when the
basalt is all blown.
Come to think of it, that much positive buoyancy could really rocket it
upwards.
ed: going to do the math...
ed:2
Wow!
This is all just calculated guess work, so don't take it too seriously...
If we assume that the motors and dive planes can only give enough
thrust in the vertical to counteract vertical drag. (they can at low
speed, but this is very optimistic as the speed rises)...
And we assume that the VIIC can blow all it's basalt and get into a
climb angle instantly (Ha!)...
Blowing basalt from 220m gets us about 14knots of vertical speed
when the boat breaks the surface.
However, the dive planes and motors, even at a 45 degree climb,
can only counteract drag up to the speed of ~4.5 knots (half the
underwater top speed at 45 degrees).
I don't have enough info to work out the drag forces, but it's a safe
bet that it will take off a lot of the speed above 4.5 knots.
A top vertical speed of 8 knots seams to be in the ball park. This is in
addition to the ~4.5 knots of horizontal velocity. that gets the VIIC
from crush depth to the surface in just under one min.
Of course, the VIIC can't blow all 102 tonnes of basalt instantly and it
can't get to a 45 degree climb angle instantly, but even with the most
conservative figures, you can expect a good knot or two of vertical
climb if all the basalt is blown.
I ran the calculations for a sinking u-boat and the effect of the ~10
tonnes of basalt that the VIIC can take on top of the neutral
buoyancy load gives it less than 1 knot of extra sink as it passes
220m.
ed3: removed some mistakes.
ed4:
As a calculated guess it would take 18-24min to sink a VIIC to 220m
without dive planes.
This is 20 Degrees Blowing Ballast:
http://i66.photobucket.com/albums/h244/Reecehk/BlowBallast-20Degrees.jpg
Can change this angle to what ever, if anyone wants to see, as well as external view, but this is about max before the view starts to look a little weird, would be nice if the crew positions reacted properly as in the photo in post #1, hopefully this will be the case in SHV.:yep:
Even slowed down to the correct speed, the
dive still looks utterly crazy.
I only have it going fast because no one wants to watch a .gif for 10 mins.
As soon as the boat reaches 45deg. it needs to pull up at an
impossible rate or it would go straight down to crush depth.
Don't forget these guys were literally crash diving for their lives. So the dive angle might look crazy, but how it looks is irrelevant, whatever gets you to the bottom fastest!
Unless you meant crazy math wise, I'll admit I don't know the math behind all this, so I'll trust you (although I'm still pretty sure they can dive at 45 and pull up before crush depth, no?).
That SH3 picture from Reece at 20 degree looks alot like that photograph! Combine that and the report; "Thereafter the angle down is normally from 12-15°, though angles up to 45 have been reported, after complete submersion." My rough guess would be that about, oh, 15-25 degrees seems like the 'normal' crash dive angle. :hmmm:
(although I'm still pretty sure they can dive at 45 and pull up before crush depth, no?).
Well, you can recover from 90 degrees if you want. It's just going to
take a lot of time because you will need to stop the motors and trim up
with basalt.
Whether or not you need to do this at 45 degrees depends on the
vertical turning circle. i.e. the rate at which you can change dive angle.
25 degrees looks much more feasible.
http://www.b3tards.com/u/57a418c694bc7c6296b3/viicdive25.gif
oscar19681
10-24-09, 09:45 AM
This is 20 Degrees Blowing Ballast:
http://i66.photobucket.com/albums/h244/Reecehk/BlowBallast-20Degrees.jpg
Can change this angle to what ever, if anyone wants to see, as well as external view, but this is about max before the view starts to look a little weird, would be nice if the crew positions reacted properly as in the photo in post #1, hopefully this will be the case in SHV.:yep:
Please show in downward angle please
http://www.b3tards.com/u/57a418c694bc7c6296b3/viicdive25.gif
Dig those gifs! :|\\
Hey I was just doing a little Das Boot reading now and came across this, looks like Buchheim has the boat crash diving at at least 30 degrees.
Page 194,
"The Chief slowly levels the boat out and orders, "Man diving stations!" The seamen who rushed forward now work their way back hand over hand up the slope. The sausages act like a scale: we're still a good thirty degrees bow heavy."
Please show in downward angle pleaseBecause of the camera angle this is about the best view or you only see the valve operator::yep:
http://i66.photobucket.com/albums/h244/Reecehk/SH320ddown2.jpg
http://i66.photobucket.com/albums/h244/Reecehk/SH320ddown1.jpg
walkirie
10-25-09, 07:43 AM
I hope the developer team can make the U-Boat dive properly in the SH5 game and fixed the almost horizontally dive bug problem of the subs in Silent Hunter 4 , in Silent Hunter 3 the developers team have made the subs dive more accurate and steeper in a tilted way ( bow dive first ) , in Silent Hunter 4 the brand new developers team forgot this and the sub dive almost horizontally
To be more exact ,actually the subs in SH4 after a while also become a bit tilted in the dive process , but in SH3 the sub become quick noticeable tilted and the stern remain much longer on the surface of the water while the bow dive deeper and deeper
http://i194.photobucket.com/albums/z58/tonschk/previe7.jpg
30 Degrees up, the dive view is stuffed in SH3 so I wont post.
http://i66.photobucket.com/albums/h244/Reecehk/SH330dUp.jpg
kptn_kaiserhof
11-01-09, 12:01 AM
dive dive
it would be good if we can manual control the dive planes
eg:dc attacks
We could in the later versions of SH2.
It wasn't really a whole lot of use.
Sailor Steve
11-02-09, 07:13 PM
It also wasn't very realistic, as the captain never manned the planes himself, and the bow and stern planes were controlled by two separate men seated at two separate wheels, and WW2 subs didn't fly like underwater airplanes. This led to complaints from destroyer players about u-boats flying up from 200 meters, popping off a shot and diving right back down again.
Of course it also led to one incident of a sub skipper reporting himself dead. It seems he put his planes on full rise and then started thinking about something else. the boat kept pitching upwards until it reached 90 degrees, and then everything broke lose and he sank.:rotfl2:
kptn_kaiserhof
11-07-09, 09:19 AM
deeper deeper
Clyde00
11-07-09, 12:48 PM
Letum, what about if a sub was surfaced at 12kts. or so, then crashed dived? As the sub reaches negative buoyancy wouldn't they have to change the planes to keep from passing crush depth?
Also wouldn't the bow be around crush depth with the stern up too far to level the dive at steeper angles past 30deg.? I have read alot on current subs and from the 60's but haven't seen any books with uboat dive operations. Surely they didn't maintain that angle past 75-80 meters?
"Survivors stated that a U-Boat could crash-dive to 15 metres (49 ft.) in 30 seconds and that the record crash-dive was 40 metres (131 ft.) in 38 seconds" From U379 VIIC on Uboat Archive
From what I've read, it seems simple enough.
1. ALAAAAARM!
2. All men go forward, the boat starts tilting up to a max of 40-45 degrees.
3. The men are called to their diving stations almost right away, the boat levels back.
So They would stay at 45 degrees for just a couple of seconds. That's just my educated guess.
Edit: more precisely I should say;
2. All men go forward and are called back almost right away
3. The boat tilts up to 45 degrees and levels back
Webster
11-07-09, 07:55 PM
where does this 45 degree angle idea come from?
has anyone ever tried just standing on any surface at 45 degrees? you would barely be able to stay in position much less do even the simplist tasks. such angles would disable your sub as well as your crew.
30 degrees is very extreme and more likely the maximum angle ever done where the crew had any chance of still functioning and recovering from
just look at the dive planes settings used, they say a lot
also ww2 subs cant take extreme angles without shifting balast around and the physics of floatation fight against you unlike an airplane that is free to do what it wants to only fighting gravity
trying to apply 20th century subs fast crash dives and how they can be made to jump out of the water manuvers to what was possible in ww2 is just wrong.
where does this 45 degree angle idea come from?
Well, personally, I get 45 degrees from mainly 2 things (as stated in my previous posts).
1. "(iii) Diving Angles.
During a normal crash dive, the angle tower increases from roughly 2 at the commencement to 10° as the bridge screen dips. Thereafter the angle down is normally from 12-15°, though angles up to 45 have been reported, after complete submersion."
http://www.uboatarchive.net/KTBNotesDivingCumulativeEdition.htm
2. and Buchheim's Das Boot (assuming he wasn't exaggerating the angle simply to make his book more interesting)
Page 194,
"The Chief slowly levels the boat out and orders, "Man diving stations!" The seamen who rushed forward now work their way back hand over hand up the slope. The sausages act like a scale: we're still a good thirty degrees bow heavy."
To me that sounds like "still a good 30 degrees" while the boat is leveling off, hence it went a little more than 30.
I think there was another place in Werner's Iron Coffins that indicated a very steep dive angle, I'll have to look at it again.
Edit: But I must say that I think the average angle was probably around 25 degrees, but for sure some boats pushed it to 45.
Being a old sub sailor myself any angle more than 20 degrees and you got problems in the control of the ship. You would be damn lucky to walk even up hill at this angle also.
The fastest dive we ever made was in 17 seconds to periscope depth and the sub was traveling at close to 18 knots when we pulled the vents. Our sub was 309' long and when you dove you put the bow and stern planes on full dive until you got to or close to periscope depth then the diving officer would give commands how to set them up and by that time you were lucky to be doing 4-6 knots as the water drag is tremendous, besides the electricians have to switch to the battery mode on the motors and I am sure there are drag time on the screws coming off of 18 knots to the 4-6 knots.
Just to let you know the Pickerel made a up bubble surface of 45 degrees and when the boat settled down the stern went to about 700', crush depth and was lucky it did not pop the after torpedo room.
I don't recall what happened but when on the Blackfin we had an incident were the after torpedo room also went to around 720' and the torpedomen back there were screaming their heads off to get theis damn pig boat up.
I suppose there were some pretty wild manuvers during the war but just can't see going either way more than 20 degrees.
Bert68
Great post Bert! :up: Always good to hear it straight from the horses mouth. Maybe Buchheim was full of it after all... If only we could get a post from somebody who served on type 7C U-boats. :hmmm:
Randomizer
11-08-09, 12:08 AM
Great post Bert! :up: Always good to hear it straight from the horses mouth. Maybe Buchheim was full of it after all... If only we could get a post from somebody who served on type 7C U-boats. :hmmm:
Remember that Buchheim was a war artist not a trained submarine officer. Even in Das Boot he never performs any duty more technical than bridge lookout so I treat his operational observations with a great deal of caution.
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