Submarine Life
 

Every so often I wonder what it would be like on a WWII sub.
So I’ll post my questions here hoping someone has a bit of info to share.

First question
While subs in the war where limited in depth they did dive several atmospheres from the surface.
I studied enough to know that the outer hull and the various tanks around the inner hull had for the most part a neutral pressure to the outside it was the inner hull that was exposed to the pressures of the ocean.

Did submariners feel or get affected by the pressure of the depths when running deep and if they did then how did they negate the Benz effect when surfacing quickly?

Or did the inner hull not compress enough to make a difference and the atmosphere inside stayed at sea level?

On a sub tour there was this smell of metal [like cast iron] and grease. With the engines running and with them being inside I imagine there would be diesel fumes too. Electric motors probably had ozone smell like a model electric train if you put it close to your nose.

I saw on tv that you got a one cotton ball per day soaked in alcohol for washing. Think it was Russia in a later era.

I watched the utube videos of the command room and bought it, but was disappointed the whole boat wasn't there. I think we need to start a whole boat mod project. I don't know how much work that would be though. Distribute the work or put money in a pot for whoever does the modelling.

Not exactly related to my question but interesting story.

I think when a sub is diving, he brings same atmospheric pressure inside as outside when surfaced, and it doesn’t change that much when deep.
Only the hull is taking the depth pressure effects, and hopefully stops it!
Otherwise it would kill all the crew from long time :yep:

+1 on Fifi's remarks...

Much like a pressurized airliner, the metal hull/fuselage structure absorbs the pressure difference between outside and inside environments and the interior pressure remains at a comfortable level... the difference between the submarine and airliner is which side of the skin is being pressurized, and the metal used for the structure.

Because a circular cross section distributes the applied pressure evenly, it is the first choice for airborne or underwater pressurized vessels, and since a sphere is a 360 degree circular cross section, it is why many deep sea submersibles' pressurized compartments are that shape.


A bit of off topic trivia -
At airliner cruising altitudes a 3 x 6 foot passenger entry door exerts more than TEN TONS of outward force against its frame. (3*6*144*8.5)... Similarly, the 18 x 18 inch window has about a TON AND A HALF of air pressure force working to push it into the stratosphere, taking the nearby occupant(s) with it :o... "We advise you keep your seat belt fastened while in your seat. Now, just sit back, relax and enjoy your flight" :hmmm:

Couple items;
1. Answer to the first question, no. When all the openings are shut, some compressed air is released to check the hull for air tight, but not much. Flood negative, sub dives, when it's under "blow negative to the mark". The mark is a point calculated to get as close as possible to neutral buoyancy, the negative tank is left partially flooded. "Vent negative inboard", after checking the outer valve shut the tank is vented, releasing more air into the sub. The pressure at that point is slightly above sea level pressure, but not very much, about the same ear popping as you experience in an airplane descending from altitude.

The water pressure outside the hull has no effect on the internal air pressure inside.

2. Since the comparison to a "pressurized" airliner was made, I feel the usual need to clear up a common myth about "breathing the same stale air for hours". That does apply to submarines, which have no way to get new air inside other than surfacing, but in airliners the air is constantly renewed from outside - that disaster movie where the "pressurized" 747 sank 200 feet deep in the ocean with subsequent rescue was pure Hollywood BS, totally impossible. Not the way pressurization works.

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Fresh outside air is pumped in at the front of the cabin at a constant rate, outflow valves at the rear are adjusted to control the internal pressure - and the outflow valves can never close all the way so there is a constant movement of fresh air from the front to the rear where the "stale" air is constantly exhausted. The reason you feel the ear popping on the way up and on the way down is because the maximum altitude inside the cabin is set to 10,000 feet, altitude restrictions are keyed to the maximum pressure differential between inside and outside (typically 8 to 9 PSI), and if they fly above that altitude the outflow valves automatically open further, which would raise the cabin altitude above the legal 10,000 foot limit. They don't try to maintain sea level pressure inside because of the pressure differential, and there's no way to override the outflow valves to make the fuselage explode at 35,000 feet.

Submarine = sealed environment, airliner = blow air in the front and vent out the back. :03:

I knew about the fresh air exchange after learning how the engines compress new air into the cabin but I didnt know its continuously vented and refreshed.


Thats new.


And so is the fact fresher air is up front.


Now I'll be reserving those rows.


Poor folks in the back get all the farts as they exhaust.