PDA

View Full Version : Will I be able to run my crew to the front of the sub to dive faster?



Charlie901
03-10-2005, 10:45 PM
Like in "Das Boot". I swear that was the best parts of the movie for me.

It really conveyed the stress and urgency of diving as fast as possible and getting every ounce of performance out of the sub.

B.T.W. What type of sub was the set/models, modeled after, in the aforementioned movie?

Teddy Bar
03-10-2005, 10:49 PM
It is done for you.

BobV_07
03-10-2005, 10:49 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Charlie901:
Like in "Das Boot". I swear that was the best parts of the movie for me.

It really conveyed the stress and urgency of diving as fast as possible and getting every ounce of performance out of the sub.

B.T.W. What type of sub was the set/models, modeled after, in the aforementioned movie? <HR></BLOCKQUOTE>


Nope, sorry. Your right though, that would have been cool!


http://adjunct.diodon349.com/photopoint/0037/0046.jpg

archer49d
03-10-2005, 10:50 PM
By the way, that wasn't standard procedure for diving on U-Boats.

BobV_07
03-10-2005, 10:51 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Teddy Bar:
It is done for you. <HR></BLOCKQUOTE>


Hmmm, i thought that was not added in the game if I remember correctly.


http://adjunct.diodon349.com/photopoint/0037/0046.jpg

scourtney2
03-10-2005, 10:53 PM
Quote: It is done for you

---------------------------------------------

What he means by this is the engineer manages the positions of the crew. Putting more people in the bow compartement will not make the sub dive faster and you will not see people running through the sub. The Devs answered this for us allready

Charlie901
03-10-2005, 11:23 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by scourtney2:
Quote: It is done for you

---------------------------------------------

What he means by this is the engineer manages the positions of the crew. Putting more people in the bow compartement will not make the sub dive faster and you will not see people running through the sub. The Devs answered this for us allready <HR></BLOCKQUOTE>



You dare say this is inacurate in "Das Boot"? http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Anyway, could you post the link where this was already discussed by the devs? I'm interested in knowing how/when your engineer manages your crew for you?


B.T.W. antone know the answer to the second part of my original post? Thanks

Leif...
03-11-2005, 12:33 AM
Of course it makes the dive go faster, say that half the crew is free to move forward than that€s about 1.5 ton moved to the front. That is not insignificant.

Leif€¦

bootysnapper69
03-11-2005, 04:32 AM
so what I am expecting is when a crash dive is ordered and you are looking in the control room, its going to sound like all hell is breaking loose but everybody is going to be standing around all calm and peaceful...

JG27_Arklight
03-11-2005, 04:34 AM
Nit-pick alert.

lol

Dominicrigg
03-11-2005, 04:46 AM
http://forums.ubi.com/images/smilies/blink.gif Will rusticles make the boat dive faster?

archer49d
03-11-2005, 07:03 AM
Well a Type VII displaces about 750-850 tons, moving less than one percent of the weight from midship into the bow will do pretty much nothing.

bertgang
03-11-2005, 08:08 AM
I think the same.

U-56
03-11-2005, 08:53 AM
One and a half tons or thereabouts is only a small part of the total of approx 700tons, but its the shift in the centre of gravity that accentuates the effect of this weight moving about the boat. There were cases of slow moving uboats at periscope depth nearly broaching the surface after firing some forward torpedoes. The sudden loss of 3 or 4 tons from the front of the boat had a considerable effect. It took an experienced crew to hold the boat steady at periscope depth, and foresee the adjustements necessary to counteract the effects of a loss or movement of weight in the boat.

Regards

Hfael
03-11-2005, 08:53 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by archer49d:
Well a Type VII displaces about 750-850 tons, moving less than one percent of the weight from midship into the bow will do pretty much nothing. <HR></BLOCKQUOTE>

I won't say you're wrong, but I'm not entirely convinced.

The small aircraft I fly weighs in at 2 tons. I can notice a significant difference simply from me or my copilot moving a seat forward or back a few inches.

Granted, it's a much higher percentage of the overall weight (maybe 5%), but on the other hand it's only moving a few inches and it's very near the fulcrum point.

So it wouldn't surprise me in the least if that "mere 1.5 tons" made a difference in dive performance.

Cheers.

-h

dagamecat
03-11-2005, 11:03 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by archer49d:
Well a Type VII displaces about 750-850 tons, moving less than one percent of the weight from midship into the bow will do pretty much nothing. <HR></BLOCKQUOTE>

actually, he is wrong :P

I'll use a see-saw analogy, if a see-saw is perfectly balanced it only takes a small mass (any amount of mass at all, really, as long as it overcomes friction), to unbalance it completely and sway all the way over to one side.

It's the same with a u-boat, it had to be perfectly balanced (by pumping water forward, for example, whenever a torpedo was fired) in order to remain straight and level. It doesn't matter what percentage mass of the boat it is, but a relatively small amount of mass will completely upset the balance, so yes, sending lots of men into the bow compartments will have a massive effect on the balance of the boat.

It might not have been a standard procedure, but I am sure that it must have been used some times, in emergencies.


EDIT: sorry U-56, didn't see your post there, pretty much said what I did, and you're right http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Charlie901
03-11-2005, 11:34 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by dagamecat:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by archer49d:
Well a Type VII displaces about 750-850 tons, moving less than one percent of the weight from midship into the bow will do pretty much nothing. <HR></BLOCKQUOTE>

actually, he is wrong :P

I'll use a see-saw analogy, if a see-saw is perfectly balanced it only takes a small mass (any amount of mass at all, really, as long as it overcomes friction), to unbalance it completely and sway all the way over to one side.

It's the same with a u-boat, it had to be perfectly balanced (by pumping water forward, for example, whenever a torpedo was fired) in order to remain straight and level. It doesn't matter what percentage mass of the boat it is, but a relatively small amount of mass will completely upset the balance, so yes, sending lots of men into the bow compartments will have a massive effect on the balance of the boat.

It might not have been a standard procedure, but I am sure that it must have been used some times, in emergencies.


EDIT: sorry U-56, didn't see your post there, pretty much said what I did, and you're right http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif <HR></BLOCKQUOTE>



Sounds credible to me!

Copyoffline
03-11-2005, 11:54 AM
I am pretty sure that it was a standard procedure on type VII boats.

Youre wrong when you say you cannot unbalance a 700 tons boat with just 1.5 tons crew. You can. Its just the matter of the lengh of lever.

Trimming the boat is nothing but the moment of force around the center of mass. The dive ruders push the boat up and down with maybe 2000 Nt. (depends on speed) Its the distance from balancing point that makes them effektive. Now youre sending 15000 Nt. like 30 meters away from the center of mass. The extra moment should be even more effective then the rudders.

archer49d
03-11-2005, 12:12 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Copyoffline:
I am pretty sure that it was a standard procedure on type VII boats.

Youre wrong when you say you cannot unbalance a 700 tons boat with just 1.5 tons crew. You can. Its just the matter of the lengh of lever.

Trimming the boat is nothing but the moment of force around the center of mass. The dive ruders push the boat up and down with maybe 2000 Nt. (depends on speed) Its the distance from balancing point that makes them effektive. Now youre sending 15000 Nt. like 30 meters away from the center of mass. The extra moment should be even more effective then the rudders. <HR></BLOCKQUOTE>

If your talking about trying to maintain a boat at periscope depth then yes, I would be wrong, but when you hit crash dive and fill the tanks the effect is negligable.

dagamecat
03-11-2005, 12:40 PM
sorry but, archer, you don't seem to understand this properly.

several of us have explained it quite well I thought, I don't know how else to do it...

all sending men forward does, is provide an extra bit of force to drive the bow down faster, putting the boat at an angle, therefore making the screws more effective in pushing the boat deeper.

as Copyoffline said, sending men forward like this may be more effective than the dive planes, although, obviously, much more impractical. But in an emergency, when you need to be completely submerged and diving as fast as possible, sending men forward as well as using the dive planes seems like a sensible thing to do.

Yarrick_
03-11-2005, 01:00 PM
And in a type IX, had it the same effect as in the VII?
What I think is that it should have had less efect, but that the performance of a IX is so poor in submerged nav that even that silghty, smallest efect is preciouss.

AzSwede
03-11-2005, 01:18 PM
But if two swallows grabed the coconut by the husk... what are we talking about?

dagamecat
03-11-2005, 01:23 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by AzSwede:
But if two swallows grabed the coconut by the husk... what are we talking about? <HR></BLOCKQUOTE>

lol. good first post. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

ZG77_Lignite
03-11-2005, 02:02 PM
How many people can fit forward of the 'center of gravity'? How many people would already be their under normal 'crash' diving conditions? In the 30 seconds a 'normal' crash dive takes, how many men are free run the 30 meters to the front of the boat (that are not already there)? Now what is the weight of increased frontal mass?

I would guess 1 ton would be stretching the amount of 'change' one could effect by ordering hands to front in an crash dive.

This would be similar to adding a 1kg weight to a 700kg steel girder (and not even at the 'tip', at that). Though I haven't done the math, it seems to me the center of gravity is not shifting significantly. It seems to me the dive planes/screws (aka speed) are the most significant 'initial' instigator of a 'crash' dive.

Not to say it wasn't attempted. As well; slow emergencies, such as the 'stuck-on-bottom' problem, could recieve larger benefits, as there would be time to shift more significant weight.

I'd love to be proven wrong, if somebody would whip out some math http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

dagamecat
03-11-2005, 02:16 PM
well remember that quite a few of these men will be coming from the rear-of-centre-of-mass of the u-boat. So you are subtracting mass from the rear, and adding it to the front, increasing the effect.

As with the girder analogy, it needs to be explained a bit better. To make the analogy more accurate, the 700kg girder must be balanced on a fulcrum at its centre of mass. If you add 1kg to one side, it will tip. This is not taking friction into account, of course, it's just a thought-experiment.

You are right in saying the screws have a big effect, and that is why sending men forward would work. They are just trying to get the boat to angle bow-down as fast as possible, so that the screws will push the boat deeper. And I reckon that for something floating in water, a deviation in the centre-of-mass like this will have a noticable effect.

Dominicrigg
03-11-2005, 02:23 PM
Read in Iron coffins how when they get stuck on the bottom of the ocean he makes them run from one end to the other, back and forth. And this dislodges the boat. If it was so insignificant then surely this too would have no effect.

30 men = about 3 tons im certain that would have an effect on dives.

Also remember, even a feather on the edge of a steel girder can tip it over if its finely balanced http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

dagamecat
03-11-2005, 02:26 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Dominicrigg:
Read in Iron coffins how when they get stuck on the bottom of the ocean he makes them run from one end to the other, back and forth. And this dislodges the boat. If it was so insignificant then surely this too would have no effect.

30 men = about 3 tons im certain that would have an effect on dives.

Also remember, even a feather on the edge of a steel girder can tip it over if its finely balanced http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif <HR></BLOCKQUOTE>

yea... i agree.


now I have another problem :S when I go to bed, I can't decide whether to read Das Boot or Iron Coffins.... hmph. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif


edit: hmm... d*mn is filtered!?

Charlie901
03-11-2005, 02:37 PM
So if your crew chief automatically manages your crew for you, in the game, does he send men foward/aft during an emergency to simulate this aforementioned maneuver (including when stuck on the bottom; if it is possible to get stuck on the bottom in this sim)???

Messervy
03-11-2005, 02:39 PM
Permanently yes, otherwise I don˙t think the devs went that deep into it.

Dominicrigg
03-11-2005, 02:48 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by dagamecat:
now I have another problem :S when I go to bed, I can't decide whether to read Das Boot or Iron Coffins.... hmph. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif
<HR></BLOCKQUOTE>

Iron coffins!! im on my second read lol to chapter 18. 2 chapters a night http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Dunbal
03-11-2005, 04:57 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by dagamecat:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by archer49d:
Well a Type VII displaces about 750-850 tons, moving less than one percent of the weight from midship into the bow will do pretty much nothing. <HR></BLOCKQUOTE>

actually, he is wrong :P

I'll use a see-saw analogy, if a see-saw is perfectly balanced it only takes a small mass (any amount of mass at all, really, as long as it overcomes friction), to unbalance it completely and sway all the way over to one side.

It's the same with a u-boat, it had to be perfectly balanced (by pumping water forward, for example, whenever a torpedo was fired) in order to remain straight and level. It doesn't matter what percentage mass of the boat it is, but a relatively small amount of mass will completely upset the balance, so yes, sending lots of men into the bow compartments will have a massive effect on the balance of the boat.

It might not have been a standard procedure, but I am sure that it must have been used some times, in emergencies.


EDIT: sorry U-56, didn't see your post there, pretty much said what I did, and you're right http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif <HR></BLOCKQUOTE>

So by your argument they shouldn't need the dive planes at all then?

I can understand this very marginal shifting of the centre of gravity increasing ever so slightly the tendency for the U-boat to adopt a "nose down" attitude, although this would probably be a small fraction of a degree. This would in theory increase the rate of the dive. How MUCH it would increase it however could only be calculated by someone experienced in the field.

My understanding is that the bow planes on the german U-boats were very small and their dive time was notoriously long. Perhaps this redistribution of weight was just enough to change the angle of attack on the planes to a more useful dive time. Perhaps it was done for psychological effect. Or perhaps it's just more cinematographic "smoke and mirrors". I seriously doubt it would cut minutes of a dive time - seconds at best. But then again in a U-boat during a war, I can imagine that every single second counts.

archer49d
03-11-2005, 05:32 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by ZG77_Lignite:
How many people can fit forward of the 'center of gravity'? How many people would already be their under normal 'crash' diving conditions? In the 30 seconds a 'normal' crash dive takes, how many men are free run the 30 meters to the front of the boat (that are not already there)? Now what is the weight of increased frontal mass?

I would guess 1 ton would be stretching the amount of 'change' one could effect by ordering hands to front in an crash dive.

This would be similar to adding a 1kg weight to a 700kg steel girder (and not even at the 'tip', at that). Though I haven't done the math, it seems to me the center of gravity is not shifting significantly. It seems to me the dive planes/screws (aka speed) are the most significant 'initial' instigator of a 'crash' dive.

Not to say it wasn't attempted. As well; slow emergencies, such as the 'stuck-on-bottom' problem, could recieve larger benefits, as there would be time to shift more significant weight.

I'd love to be proven wrong, if somebody would whip out some math http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif <HR></BLOCKQUOTE>

Pretty much my point right there, it's a time issue. I've been on various boats over the years, even on Romeos and Foxtrots (driect descendants of the XXI) and been through an Emergency dive on a Foxtrot and (less relevant) an Akula. I fired off an e-mail about this topic to Jarek (former CO of a now decomissioned Foxtrot in Poland), and U-Boat historian. He confirms what I stated, that though the boat may experience massive changes when it is trying to remain in a very still position, the same change in mass positioning will not make enough of a difference in the short amount of time it takes to conduct an emergency dive on a u-boat to warrant a charge to the torpedo room. Think about how long it takes to run through a U-boat. 50 Yards, sprinting most can do that in 5-9 seconds. Now try running through bulkhead doors, you can't, and you can't just jump/swing through them either, you'll break your neck. So by the time that enough crew gets into the forward compartment to bring the bow down the planes have already broken below the surface, and the rest of the boat follows within a few seconds. Making any effect you feel from it insignificant to the action as a whole, my point the whole time.