Request for accuracy for a film...

[pbnj]

Submarine Escape Immersion Equipment - Wikipedia, the free encyclopedia
This is the current state of the art, or so Wikipedia says. Which is rated to 600 fsw. Just for clarification, if you trap air at 1 atm and immediately go to 15 atm, the air will instantly compress to 15 atm. the practical effect is that a dry suit will lose all its volume, 6 liters of air (about 1.5 gallons) will become 400 ml (less than 1 pint), your lungs would probably collapse in an irreversible way. Even more importantly a traditional dry suit would collapse onto you like shrink wrap on a ding-dong, rendering you completely paralyzed. The rapid implosion of your eardrums will prevent you from hearing your own scream of agony (but with no air in your lungs, I wouldn't worry about screaming anyway). If escaping from a sub isn't the main plot issue is should be, because you are more likely to survive a high speed car chase in that doing a blow and go from 600 fsw. Interestingly, if you start at depth and breath out you can actually make it to the surface on one breath (although, there is going to be the greates volume change closer to the surface.)

So, in the scenario above, they're better off trying to go from point to point just on controlled exhaling? Forget any type of trapped air?

Would any type of ear plugs or stuffing do anything to prevent/lessen the reaction at that depth? I'll blow their ear drums if there's no other way. They'll take blown ear drums over drowning.

I don't need them dancing on the surface at the end. Just alive and with odds on continued survival, even if it requires treatment.

 

[CT-Rich]

If the submersible begins to flood, lets water in, and air is compressed by the water entering, then you can have a pressurized submersible at that point, though there is a much reduced area your heroes are within....
If they are going to make a mad dash to the surface after the stop at the bell, or if they are going straight to the surface from the flooded submersible, you absolutely do NOT want them on a Helium mix ..You want them breathing air.....If they were breathing a helium mix, they could not surface quickly...if breathing air, it does not supersaturate anywhere near as easily as trimix ( supersaturate equals fizzing) , and a 300 foot per minute ascent could easily be survivable from the submersible--little time for nitrogen saturation, which is why freedivers can do a drop to 300 or 400 feet and not get bent.
.
The smart way up without fins, is probably to have some kind of upside down bag full of air, held by a rope, that will act as a float to drag them to the surface rapidly.
For this reason, I'd pass on the bell, and go straight for the surface the moment I could get into the water.....even a 400 foot per minute ascent, with ascent occurring immediately, could be survivable as long as they exhaled all the way up ( and did not have asthma)....Some individuals might get bent if they had a PFO or bad genetics....most should be just fine. I would assume no oxygen will be available on the surface---though that would be ideal if possible, to mitigate any possible dcs , until a chamber ride was possible.

They do need a mask to make it feasible...though someone with skills could do it without a mask....and you probably could MacGyver a Dry suit with the material you suggested--with lots of warm clothes inside for insulation, as long as the escapees know that without an OPV valve, they will have to dump air out of suit sleeves or neck area as they ascend.....some place that can not be held by duct tape, but must be elastic to allow for the dumping and sealing.

Free divers do those dives in hydrodynamic suits, getting any where near those ascent rates in anything else would be tough. If the sub was in the tropics, they could surface into water in the 80s which would help with the hypothermia. An ascent bag and skipping the bell would definately be the simplest solution. The chap who escaped the sub from 200 fsw passed out before reaching the surface but made it anyway. This supply sub could have some compressed air cylinders on board. If the diver kept their head in the lift bag they could breath all the way to the surface, like the escape suits.

 

[pbnj]

If the submersible begins to flood, lets water in, and air is compressed by the water entering, then you can have a pressurized submersible at that point, though there is a much reduced area your heroes are within....
If they are going to make a mad dash to the surface after the stop at the bell, or if they are going straight to the surface from the flooded submersible, you absolutely do NOT want them on a Helium mix ..You want them breathing air.....If they were breathing a helium mix, they could not surface quickly...if breathing air, it does not supersaturate anywhere near as easily as trimix ( supersaturate equals fizzing) , and a 300 foot per minute ascent could easily be survivable from the submersible--little time for nitrogen saturation, which is why freedivers can do a drop to 300 or 400 feet and not get bent.
.
The smart way up without fins, is probably to have some kind of upside down bag full of air, held by a rope, that will act as a float to drag them to the surface rapidly.
For this reason, I'd pass on the bell, and go straight for the surface the moment I could get into the water.....even a 400 foot per minute ascent, with ascent occurring immediately, could be survivable as long as they exhaled all the way up ( and did not have asthma)....Some individuals might get bent if they had a PFO or bad genetics....most should be just fine. I would assume no oxygen will be available on the surface---though that would be ideal if possible, to mitigate any possible dcs , until a chamber ride was possible.

They do need a mask to make it feasible...though someone with skills could do it without a mask....and you probably could MacGyver a Dry suit with the material you suggested--with lots of warm clothes inside for insulation, as long as the escapees know that without an OPV valve, they will have to dump air out of suit sleeves or neck area as they ascend.....some place that can not be held by duct tape, but must be elastic to allow for the dumping and sealing.

Is a 1 or 2 breath stop at the bell to retrieve something for buoyancy out of the question? 10 seconds in and out? Or is even that enough to make it much worse for the ascent?

 

[danvolker]

Is a 1 or 2 breath stop at the bell to retrieve something for buoyancy out of the question? 10 seconds in and out? Or is even that enough to make it much worse for the ascent?

There is no such thing as a 1 or 2 breath stop like that......If you stopped at the bell, it would be probably a minute wasted getting what you wanted, breathing up for a breath hold again ( even with the exhale), and getting back into the water.
What is the item or issue that makes you want to stop them at the diving bell?

 

[pbnj]

Free divers do those dives in hydrodynamic suits, getting any where near those ascent rates in anything else would be tough. If the sub was in the tropics, they could surface into water in the 80s which would help with the hypothermia. An ascent bag and skipping the bell would definately be the simplest solution. The chap who escaped the sub from 200 fsw passed out before reaching the surface but made it anyway. This supply sub could have some compressed air cylinders on board. If the diver kept their head in the lift bag they could breath all the way to the surface, like the escape suits.

Now that is definitely interesting. This is a mid Pacific setting. The compressed air into an ascent bag wouldn't collapse around their head as soon as they exited?

---------- Post added May 5th, 2015 at 10:33 PM ----------

There is no such thing as a 1 or 2 breath stop like that......If you stopped at the bell, it would be probably a minute wasted getting what you wanted, breathing up for a breath hold again ( even with the exhale), and getting back into the water.
What is the item or issue that makes you want to stop them at the diving bell?

Something for buoyancy to make the ascent faster, which they don't have in the submersible they're leaving. I could give them something in the sub, but movies are about making your hero work and risk danger for what they need.

Would a diving bell have compressed air cylinders like Rich mentioned? If they were to stop there quickly for the materials to make an ascent bag, would even that exposure to the Bell atmosphere create way more trouble than its worth, physically?

 

[danvolker]

Now that is definitely interesting. This is a mid Pacific setting. The compressed air into an ascent bag wouldn't collapse around their head as soon as they exited?

The air in the submersible is under pressure from the water that pushed it in.....so the bag has high pressure air in it equal to the water outside( there is nothing to make it collapse) , as soon as the divers evacuate..and the air expands in the bag, and excess pours out the bottom as they ascend...as would the dry suit...

In the mid-90's, we used to do "Blow and Go" on 280- to 300 foot deep dives on air....our spearfishing dives for monster fish on deep wrecks and on pinnacles ( Fort Pierce to Lauderdale).
With Blow and Go, when the group gets ready to ascend, each diver fully inflates the wing/bc, and you begin rocketing upward at an insane speed. The Overpressure relief valve on the BC, actually screams so loud with the escaping air, that the high pitched shrieking HURTS your ears, and there is a huge monster of a bubble cloud, below you, chasing you and enveloping you at the same time. It was wildly other-worldly.
At 100 feet, you dump your BC, and comes to a complete stop for a minute, then begin a slow ascent to the deco stops starting at 50 feet.
I bring this up, not for the deco part, but for the rapid part of the ascent...and your guys would have no need for the 100 foot stop--they would go straight to the surface.

 

[pbnj]

The air in the submersible is under pressure from the water that pushed it in.....so the bag has high pressure air in it equal to the water outside( there is nothing to make it collapse) , as soon as the divers evacuate..and the air expands in the bag, and excess pours out the bottom as they ascend...as would the dry suit...

In the mid-90's, we used to do "Blow and Go" on 280- to 300 foot deep dives on air....our spearfishing dives for monster fish on deep wrecks and on pinnacles ( Fort Pierce to Lauderdale).
With Blow and Go, when the group gets ready to ascend, each diver fully inflates the wing/bc, and you begin rocketing upward at an insane speed. The Overpressure relief valve on the BC, actually screams so loud with the escaping air, that the high pitched shrieking HURTS your ears, and there is a huge monster of a bubble cloud, below you, chasing you and enveloping you at the same time. It was wildly other-worldly.
At 100 feet, you dump your BC, and comes to a complete stop for a minute, then begin a slow ascent to the deco stops starting at 50 feet.
I bring this up, not for the deco part, but for the rapid part of the ascent...and your guys would have no need for the 100 foot stop--they would go straight to the surface.

Wow, that would make quite a visual. How fast would it take you to get from 300ft to surface at that rate?

 

[danvolker]

Wow, that would make quite a visual. How fast would it take you to get from 300ft to surface at that rate?

Less than a minute.
One time a British diver that was with us, had his OVP valve fail.....I saw this at around 150 feet that he could not dump......and began trying to help him....His 100 pound lift monster wing had so much lift, in a few more seconds we were at the surface...from a 285 foot dive for 25 minutes.....And feeling fine...though hoping that everything I had read about hyper saturation of air was true...and that he could puncture his wing and go straight back down to 100 feet....and be fine.....with no dilly dallying on the surface.....

I was back down to 100 feet in about 30 seconds, and still felt fine...then did normal deco from 50 foot stop on....probably a little more pure O2 than normal at 20...but the 3 of us involved ( one other diver had also tried to assist), all felt fine, and had zero dcs.

The ride was actually fun, if you could factor out the concern that you might die
But at least from then on, I knew that the theoretical on supersaturation was in fact true--that air does give you some time before fizzing can happen.

I should do a video of a 280 foot "Blow and Go" some day....with audio, and the wall of bubbles chasing, that would be an awesome video !!!
Only problem is it would mean doing deep air, and we know it is kind of ignorant to do this, with the lack of narcosis or Ox fox that Trimix delivers. Back in the mid nineties, we did not know any better. Trimix was devil gas

 

[pbnj]

Okay, let's forget the Bell.

Our guys know they need to get as far up as they can before bailing on the sub. They know they need to improvise a suit for the cold. They know they need to make an ascent bag. They're aiming for 200ft, but they know at 500ft that it's just not going to get there.

Suit up, flood the sub and make the ascent bag from the high pressure air.

Do they take a breath and try to make it all the way up with controlled exhaling?

Or sip from the ascent bag as they go?

Or exhale to low-mid volume and hold it until they reach the surface so their lungs are not inflated on the ascent?

Is there anything I can do about their ears, or are they just going to have to chalk blown eardrums up to the experience?

Are they still going to need any decompression time at the surface in this scenario?

Could you MacGyver an OPV into the ascent bag (I really love that speed/bubble visual now)?

Thanks once again, all. This is for a 10-15 segment of a film, but now I kinda want to write a whole movie about all this stuff.

 

[danvolker]

Okay, let's forget the Bell.

Our guys know they need to get as far up as they can before bailing on the sub. They know they need to improvise a suit for the cold. They know they need to make an ascent bag. They're aiming for 200ft, but they know at 500ft that it's just not going to get there.

Suit up, flood the sub and make the ascent bag from the high pressure air.

Do they take a breath and try to make it all the way up with controlled exhaling?

They can hit the surface in about a minute with the ascent bag pulling them up. It might be wise to make a harness, as the rope will be pulling very hard on the way up, especially with the drag of a DIY dry suit...

Or sip from the ascent bag as they go?

They could, but should not really need to....the problem with sipping is getting to the bag, unless you started almost physically inside it--meaning zero control or visual to navigate around submersible or any other structure involved at depth. Remember, with a large enough bag, you are at the surface in about a minute. Not that long, and there is not much exertion beyond hanging on.

Or exhale to low-mid volume and hold it until they reach the surface so their lungs are not inflated on the ascent?

You exhale at what feels to be a comfortable rate on the way up....it is actually quite intuitive....it is as easy as exhaling

Is there anything I can do about their ears, or are they just going to have to chalk blown eardrums up to the experience?

Ears clear fast going up...None of us EVER had any problems on Blow and Go ascents....this is a non-issue.

Are they still going to need any decompression time at the surface in this scenario?

This depends on how long you put them in pressurized water...how long from when the submersible lets all the water in that shrinks the air space, and compresses the air to your equilibrium with the 400 foot depth. If you can limit this to maybe 2 or 3 minutes ( sort of required so that they can equalize their ears as the pressure comes up--they will need to squeeze their nose and blow non-stop into their ears)...Keep the whole bottom time under 5 minutes and you are still in the range of what freedivers have done without DCS.....take it to 10 minutes and DCS is most likely going to happen, and require O2 on the surface, then a chamber ride....or at least a bottle of O2 they can go back down to 20 feet with and hang out for 20 minutes.

Could you MacGyver an OPV into the ascent bag (I really love that speed/bubble visual now)?

No need for an OPV with an open bottom bag.....look up some of the open bottom "lift bags" online. Dry suits would need an OPV, but pulling the neck seal or wrist seal open will manually dump instead.

Thanks once again, all. This is for a 10-15 segment of a film, but now I kinda want to write a whole movie about all this stuff.