The Navy has developed a submarine escape trainer. Presumably, it assumes that your sub isn’t too deep.
But while I assume that it’s part of the training, I see no mention of the need to allow the air to flow out of your lungs as you ascend. The pressure in them at depth is going to be several times that at sea level, and if you hold it in, you’re guaranteed a pulmonary embolism, likely fatal. Also, surface rescuers would have to have a hyperbaric chamber handy, otherwise those rescued are almost certainly gong to get badly bent (again, possible fatal, certainly injurious), unless the accident from which they are escaping occurred shortly after submerging. But if you’re going to float around for awhile before being rescue, bends seem almost certain. On the other hand, I guess it still beats drowning or asphyxiation at depth. Sounds sort of like an ejection seat for an aircraft — attempted suicide to avoid certain death.
[Update a couple minutes later]
I don’t know what current training requirements are, but I think it would be worthwhile to give scuba training to all submariners, to reduce the chances that they’ll hold their breath while ascending. Rule number one of diving training is to never hold your breath underwater. Of course, it’s an easier rule to obey when you have an air supply…
[Update a few minutes later]
Yes, as corrected in comments, bends isn’t (aren’t?) an issue. I’d forgotten that subs are maintained at one atmosphere.
I was taught to breath out on the way up in the old trainer (“Ho-Ho-Ho” or something like that). As far as bends go, submarine interiors are at ~normal atm pressure, and as I understand the bends, you have to have a change in gas pressure you are breathing. Even though you are at depth when the ascent begins, you aren’t ever breathing air at the pressure.
As far as bends go, submarine interiors are at ~normal atm pressure, and as I understand the bends, you have to have a change in gas pressure you are breathing.
I should have been aware of that (and may even have been, in my pre-senility days). That’s why the things have to be built to take so much pressure, I guess. And why they’re structurally limited in depth. Otherwise you’d bend the whole crew in a rapid ascent.
jrman – you are correct – bends are due to a decrease of pressure, allowing nitrogen to bubble out. Really shouldn’t be an issue in a submarine escape.
I could swear I remember seeing pictures of submariners practicing in some sort of underwater-escape simulator when I was in grade school. Am I suffering from false memory syndrome?
Also, I don’t understand this statement: “those rescued are almost certainly gong to get badly bent… unless the accident from which they are escaping occurred shortly after submerging.”
To the best of my knowledge, submarines do not vary internal pressure or gas mixture while submerged. Why would the length of time the submarine is submerged affect the likelihood of getting the bends? The only time a submariner is breathing high-pressure gas mixture is when he’s in the escape lockout chamber.
I would expect that the submariners are at sea level when they go into the chamber. Maybe they would pre breathe pure Oxygen for a few minutes to saturate their blood. Because once, they flood the chamber, they won’t be holding their breath. I would expect the pressure to squeeze down their ribcage. If you are at 200 feet. That would be about six atmospheres or 90 psi. I expect it will be quite a relief to get to the surface.
According to the comments, there used to be one at Pearl, but it was shut down some time ago.
Here’s a stupid question that I’ve never understood about this, though…
How is it that you can breathe 1-bar air at 500′? Obviously, a scuba diver can’t, or they wouldn’t have to deal with the bends (or lung rupture) from rapid ascension in the first place. So, how does an escaping submariner push 1-bar air into his lungs when his lungs are being compressed (along with the rest of him) with crushing water pressure? What keeps the flexible hood of that suit from compressing against his head?
Not being a submariner, my guess is that they have to equalize the pressure in the diving chamber before they can open the hatch. If so, then the escaping submariner’s breathing equipment would also be at equal pressure with the outside environment.
Not being a submariner, my guess is that they have to equalize the pressure in the diving chamber before they can open the hatch. If so, then the escaping submariner’s breathing equipment would also be at equal pressure with the outside environment.
I am a former submariner and this is correct. After the escape chamber is pressurized the escapees (usually five at a time) have a certain amount of time (which varies with depth, the deeper, the quicker) to begin their ascent to avoid being bent. I remember the last line on the chart being 600 ft – 45 seconds. As previously mentioned, escapees must exhale continuously (ho!-ho!-ho!) during ascent. Do not ascend faster than your bubbles!
The US Navy once had a “Submarine Escape Training Tower” at the New London CT Submariner training facility that was about 100 feet tall, 20-30 feet in dia and filled with water. Trainees entered one of 3 chambers along the side at 20 feet depth, 50 ft and the full 100 ft. The chamber was flooded and the trainee rose to the top as if escaping from a sub sunk in shallow waters. The New London tower has since been razed.
Ed:
>I could swear I remember seeing pictures of submariners practicing in >some sort of underwater-escape simulator when I was in grade school. >Am I suffering from false memory syndrome?
Nope. There was a trainer at the New London Submarine School until quite recently that was pretty much a 100′ high tower filled with water, and I believe predated World War II. The new trainer is its replacement.
>I don’t know what current training requirements are, but I think it >would be worthwhile to give scuba training to all submariners, to >reduce the chances that they’ll hold their breath while ascending. Rule >number one of diving training is to never hold your breath underwater. >Of course, it’s an easier rule to obey when you have an air supply…
I believe the current logic is that it’s easier and faster just to teach them to exhale by going through shallow sessions in the training tower, rather than taking the time needed for a full SCUBA certification. There aren’t that many similarities between submarine escape equipment and SCUBA gear in any case.
Another factor, of couse, is that the U.S. Navy sub force has traditionally operated in the deep oceans, meaning that a lost submarine was unlikely to sink in water shallow enough to allow the crew to escape (or, for that matter, for the hull to remain intact). Therefore, the logic goes, it’s better to spend the available training time teaching recruits to fight casualties and prevent the boat from being lost in the first place. Whether that will change with the new emphasis on “littoral” operations is a good question.
Thanks, I feel much relieved.
Considering how common false-memory syndrome seems to be on this site (people who claim to have heard General Bolden say he’s ending human space exploration, etc.), I was afraid it might be catching. 🙂
So, why does Wired call this “the first of its kind in the US”?
Ed, I’m fairly sure that my Dad trained at a similar submarine escape simulator back in the 50’s, and I don’t think it was one in Connecticut. I’ll have to double-check with him where it was.
Regarding Rand’s comment about the bends, there was training in using the mechanism both with and without some sort of breathing apparatus, I don’t know much about it, though. I do know that they were expected to limit their ascent speed to lower than whatever bubbles they exhaled to limit how much of the bends they got. (I would suppose that the limited amount of time they would spend breathing high pressure air would limit the amount of dissolved nitrogen in their blood to begin with.)
A quick google search reveals that previous mechanisms used by the Navy were the Steinke Hood and the Momsen Lung.
The Wikipedia article on Charles Momsen is a much better historical overview of the historical development of submarine rescue than either of the two above articles, though.
Oh, and Rand? Momsen was the guy who invented the escape mechanism, the breathing mechanism, _and_ was the Navy’s point man in troubleshooting the massive problems they had with torpedoes in the early part of WW2. And invented the helium-oxygen mixture for deep diving.
Ed, I’m fairly sure that my Dad trained at a similar submarine escape simulator back in the 50’s, and I don’t think it was one in Connecticut.
There was one at Pearl Harbor as well as one at New London, CT.
Not long ago I read the book Disasters of the Deep by Edwyn Gray. It’s a chronicle of submarine accidents and disasters from the earliest times up until the Kursk. Some were just mishaps that did not result in loss of life. It excludes combat losses, but it also serves as a sort of history of the development of submarines. I recommend it for anyone who is interested.
Indirectly related, but if submarines interest you (or quite possibly even if they don’t) Blind Mans Bluff is a great read.