Can a sub really sink itself beyond recovering by opening a tube? - Ice Station Zebra (1968) Discussion

[–] fiat0903 15 years ago

Fair question. In theory, a flooded forward compartment should not cause the boat to descend at that rate. It might tip downward. A boat can be caused to rise by releasing compressed air into the ballast tanks. (There are about a dozen compressed air tanks with 3000 psi air. At 3000 psi, a cubic foot of air is reduced to the size of a dime.) In fact, blowing tanks is the normal way to surface. Blowing the forward ballast tank might counterbalance some, if not all, of the water in the forward compartment.

But this is Hollywood. There were so many liberties taken with reality that there is no telling about this boat. For example, any boat with that design would not have the room that this boat has. Real boats of that vintage are cramped.

Another bit of unreality during the descent is the lack of hull noise. As a boat submerges, the water pressure increases. This causes the hull to be compressed. The boat quite literally shrinks. The amount is small but it does shrink. (If it did not shrink, it would collapse.) As the hull shrinks there is an eerie creaking and groaning. As fast as the boat in the film descended, the hull noise would have been almost constant, almost staccato.

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[–] slainzcasl-1 15 years ago

At school I spent two weeks on an ocean liner. They told us that as long as the fire doors were closed, she could stand to have quite a substantial amount of water on board before listing and going down. I would suppose a sub. is the same.

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[–] Radalan 15 years ago

"At school I spent two weeks on an ocean liner... I would suppose a sub. is the same."

Ocean liner and sub? The same?

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[–] leforcat 15 years ago

fiat0903, you're quite correct in what you say. Another thing almost always pushed by Hollywood films is how close to other objects such as ice or OTHER subs those boats manage to navigate just by way of sonar - in reality the margin must be much greater. There's more: depth charges always explode close to the hull, in reality the boat would be doomed, anything closer than 50 yards can cause severe damage, at least on boats of WWII design, and up to the 50s. But hey, it's not reality - it's cinema!

The squeeking sound caused by compression when submerging however?... I served close to one year on a sub designed in the late 70s and I can't recall any such sound at all. Perhaps you served ona different kind of boat ;-)

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[–] Gatorman9 15 years ago

I don't think Fiat was ever on a boat. I think he has read a book by Tom Clancy or something and is theorizing. And while I was on some boats, when it comes to WWII I've been stuck with reading a lot of books and talking to some vets, and they sometimes report those old relatively thin-skinned boats making a lot of noise with at least large magnitude, rapid depth changes. I'm afraid that based upon that (and from reading allied destroyermen's anti-U-boat accounts)I also have to disagree with what you have said about depth charges. In fact, 50 yards is practically as good as a mile away with good old-fashioned WWII ordinance. To be assured of a kill, you needed almost a direct hit; as best as I can recall now, testing done either during or shortly after the war showed that a depth charge exploding more than only 30 FEET away was unlikely to cause vital damage. That is why WWII submariners' standard procedure of dodging depth charges with sharp turns made AFTER the charges were dropped right on top of them enabled them to consistently live to tell the tale. For once the movies got something right in that regard, too.

Last but not least, in *Ice Station Zebra* the boat was using ACTIVE sonar and the way it was depicted in the movie is close enough to reality to be acceptable for a movie. Read *Nautilus 90 North* by its CO, Anderson, about how they used under-ice sonar to navigate and find leads for surfacing through the ice and you will see where this is coming from in the movie. Passive sonar, on the other hand, is a much trickier deal, although with a lot of practice you can tell quite a lot about noise-emitting things that are very close to you. I never had the chance to learn as much as I would have liked about that, however, since I was only in boomers, rather than any fast-attacks, even though I was assigned to sonar on both my boats.

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[–] leforcat 15 years ago

Well, all I really know is that a charge dropped 50 yards away sounds quite a lot (and feels considerably less) - that's because they've only dropped charges on us for practice at that safe distance, and, as I assume they didn't really wanted to sink us, the safety was more than adequate :-). What the actual minimum safety distance was would be either actually quite unknown (because how can you establish that for sure?) or too classified even for me to know.
On the other hand, I really doubt you had to come as close as to a near-hit, because it seems unlikely they'd ever sink any boat in WWII, the odds would be too high - while in fact they did. But I can't be sure... You may be right.

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[–] Gatorman9 15 years ago

That's because you haven't studied WWII ASW tactics. They always involved running directly over the target (as painful as it is to refer to a submarine with that term!) to make an attack. Yes, a near-direct hit was generally required. The operative number, if I recall correctly, was about 30 feet - and definitely not yards. This figure came from actual testing done by the Navy either during or shortly after the war, as very naturally some knowledge of this subject beyond mere guesswork was desirable, and as money and other resources to do such testing was finally available, but nevertheless was generally consistent with the experience of both submarine and ASW forces in actual combat. I still remember how surprised I was to read this 20 or 30 years ago, but eventually I came to have no trouble accepting it as I learned and understood more about contemporary ASW and counter-ASW tactics.

It is because you had to get so close to score a kill that the original attack technique of merely rolling drum-shaped depth charges off the stern of the attacking ship had to supplemented with side-throwing Y- an K- guns, and finally with forward-thrown hedgehogs, which were intentionally designed so that they would not even explode at all unless they made physical contact with the target. This latter weapon was considered the key to obtaining consistent kills on submarines that until its adoption could be tracked quite well but which always tended to have a reasonable chance of wiggling loose as the attacking vessel passed over it. Indeed, even with hedgehog, you could still miss.

It was not for nothing that successful prosecution of a submarine contact could take hours and at least two or three surface skimmers working together as a team; a "hunter-killer group" would include a small aircraft carrier PLUS about five ASW escort vessels, and it still typically took them hours, assuming the U-boat contact didn't manage to evade them altogether, even with all of them banging away with active sonar. Check out, for instance, *U-505* by RADM Daniel V. Gallery (USN, ret'd). This situation only improved with the development of reliable "homing" torpedoes equipped with their own active sonar being used in place of depth charges, and of course by the 1960's there were nuclear devices used to eliminate the need for anything like a direct hit. By the end of the 70's these in turn were withdrawn form service.

I wish I knew a good one-stop source of info about all this I could refer you to, but I learned all of this stuff so many years ago I don't remember what the better sources I found were. Chances are that Norman Friedman's *US Submarines, 1900-1945* (approximate title) would shed some light on it, along with any book that goes into detail regarding WWII-era ASW tactics. You can probably find some info on depth charge evasion tactics in submarine commanders' wartime memoirs like *Clear the Bridge* (whose author, RADM Richard O'Kane (USN, ret'd), I once spoke to personally about this) or possibly CAPT Edward L. Beach's (USN, ret'd) non-fiction *Submarine*.

The reason that the "familiarization" depth charges you talk about were so far away was to ensure beyond doubt that there would be NO damage to the submarine in question. Moreover, all WWII submariners who have discussed what it's like to be depth-charged say that unless they were pretty far off, it was just plain god-awful inside the boat whether or not they were not right on top of you.

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[–] leforcat 15 years ago

Thanks for the info!

I may add that in order to attack a boat with charges you need to 1. find it and 2. stay in touch. Whenever we exercized it with the anti-sub choppers we would surface so that they'd 'find' us, then we'd dive, and then they'd loose contact for good after only a few minutes. It was embarassing. I wouldn't even mention it, but many years has passed since, and I certainly hope they've improved!

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[–] fiat0903 11 years ago

All the boats I was on were launched in 1943. All had 300 side numbers. My statements were based on those boats.

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[–] 1shado1 10 years ago

In fact, 50 yards is practically as good as a mile away with good old-fashioned WWII ordinance.

"ordnance" :)

Now if that bastard so much as twitches, I'm gonna blow him right to Mars.

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[–] Gatorman9 15 years ago

I qualified aboard SSBN656 (USS George Washington Carver) in 1980, and subsequently trained aboard another boomer as diving officer, and I disagree (and heartily, I'm afraid). Merely moving a dozen or so decent-sized men to the forward room will alter trim perceptibly to where the diving officer will feel compelled to pump water aft, and on a submarine more than twice the likely size of the one in the movie. The forward room is a large space and will hold a lot of water, and the rate of ingress of water through an opening 21 inches in diameter at sea pressure will fill it entirely in as little as a minute, tops, depending upon your depth. This will add far greater weight to that end of the boat than a dozen men will, and in a short period of time. Because all the water is staying up at the forward end of the boat, you can expect to develop a significant down-angle that the planesmen cannot hold pretty promptly. Indeed, we used to practice this type of casualty on the dive training simulator at the former FBM Training Center in Charleston, South Carolina, and that is just what happened. In real life a hole that size while submerged is a nightmare casualty that will get you every time if you do not respond correctly and promptly, if then.

Consequently, I never thought that this sequence was especially "Hollywood" at all. In the aforementioned simulator it looked a lot like the way it did in the movie. To begin with, in the movie the captain orders the blowing of all main ballast tanks as soon as the casualty is reported. This was obviously inspired by an extremely competent technical advisor. From my experience with the simulator, it is what saved the ship. Waiting to do that until other measures had been tried and failed in the simulator resulted in the loss of a boat at least twice this one's presumed size. This is because the forward momentum the boat had prior to the casualty is now directed downward as well as forward, because of the trim problem, and the fact that the boat is taking on water faster than it can expel it by blowing main ballast means it is still getting heavier by the minute. All of this is dragging the boat ever deeper by the second.

Even once the flooding is contained (in this case by getting the tube outer door shut), so that you are now shedding weight as the blow of main ballast continues, the boat has tremendous downward momentum that must be reversed before it gets so deep that it reaches design depth, at which point it is assumed that you'll start having a lot more flooding from blown packings, gaskets, fityings, and the like. Worse still, if you plunge past design depth quickly enough, you could have a hull rupture and implosion such as appears to have happened to SSN589, the USS Scorpion, or a complete hull disintegration as appears to have happened to SSN593, USS Thresher.

The problem is not a static one of looking at weights but a dynamic one, looking not only at the boat's overall weight but that weight's bow heavy distribution and the momentum of the boat in the downward direction, as well as sea pressure effects. I still remember a very experienced chief petty officer trying to get it through my thick head as I was learning this that as the boat goes deeper, the steadily increasing sea pressure fights against the high pressure air (on the boats I was on, 4500# air, not 3000) trying to expel the water in the main ballast tanks. You can get to the point long before reaching design depth that countervailing sea pressure keeps even all your air banks' 4500# air sufficiently compressed that you can't ever get all of the water out of the main ballast tanks, so that if you haven't arrested the boat's downward momentum by that point the problem will get nothing but worse as you continue to go deeper.

However, there are certain other things about this sequence that I have always wondered about. One thing that has never made sense about this sequence was the pressurizing of the compartment, because once the torpedo tube outer door was secured it would have no effect; perhaps that was SOP in 1968 as a backup precautionary measure, but we would not have done it in the 1980's unless it were specifically ordered by the captain.

There are any number of other technical things I could nitpick about in this movie, but the fact is that it is more accurate than not in regard to technical matters, and it is obvious that the writers and director, John Sturges, went to a lot of effort to pay respect to technical issues in comparison with just about anything else regarding submarines that you are likely to see.

Having said all that, one thing that is worth mentioning, however ironically, is that this casualty itself could never have occurred as portrayed in the film in the first place, because, as Rock Hudson says with such admirable succinctness in the movie, one thing that can't happen on a submarine is to have both ends of torpedo tube opened at the same time. Regardless of Patrick McGoohan's (may he rest in peace) explanation, this is because the thing that isn't mentioned here is that the inner and outer doors on US submarines are **mechanically** interlocked for the very purpose of preventing this kind of problem. You can't open both at the same time anymore than you can tow your rear-wheel-drive pickup truck forward with the transmission stuck in reverse, for just as you would have to disconnect the drive shaft to do that, so too you would have to disconnect the mechanical interlock, which is not only not mentioned by Patrick McGoohan, but because it is plainly visible right alongside the tube would be spotted by anyone working there at a glance. Moreover, submarine torpedo rooms always have a watchstander present 24 hours a day while at sea, and they are popular hangouts for off-watch crew looking to socialize, if not actually sleeping spaces for some crew as in all World War Two submarines and many subsequent nuclear-powered boats, so that numerous other people would be expected to be there at all times. Worse still, I have to wonder about the procedure of using a torpedo to blow a hole in the ice. Apart from the danger this might represent to the submarine, I have to wonder how you get one to detonate when and where you wanted it to - maybe they were going to use a vintage MK. XIV or other weapon equipped with a contact exploder? Certainly I don't know of any contact exploder in the later Mk. 37 and 48 torpedoes, which were designed to be used in combat relying on the presence of the magnetic field of a steel target to detonate under normal circumstances. Here, at last, you can find some "Hollywood" in this otherwise very plausible sequence.

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[–] radiodaze 15 years ago

Thanks for the excellent explanation about submarine operations! I've heard from friends of mine who were on subs tha "Ice Station Zebra" is probably the most accurate Hollywood depiction ever made. Of course, "Das Boot" was made in West Germany, but I think these are easily the top two.

I had to laugh years ago when I saw "Crimson Tide", since I'm pretty sure even the captain wouldn't have a Jack Russell terrier on board...

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[–] Gatorman9 15 years ago

Read my review of *Crimson Tide* sometime - I thought it was probably the single most disappointing movie experience of my life.

*Das Boot* is really outstanding in many ways, but given the different timeframe and the fact it was not about a US submarine makes it difficult to compare with ISZ. Myself, I want to see the the US counterpart to DB, i.e., a movie made just as well but about the American submarines, but I doubt seriously it will ever be made.

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[–] djmils 14 years ago

Thanks for all the info. I was curious about this question myself, especially pressurizing the compartment after the torpedo door was secured. I love submarine movies, but my technical knowledge is slim to none.

I am still having trouble understanding how a full redline reverse couldn't arrest the downward momentum more quickly. Or maybe since the sequence was actually pretty fast, they screws did do the job in the correct time frame?

Also, I believe that the Captain mentioned that they were going to detonate the torpedo electronically. I took it that he meant that the torpedo had a remote control or wire guide, I don't know if these existed back then.

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[–] Zipper69 13 years ago

Just watched this once more on TCM and although the conversation between the captain and his torpedo officer is brief and rather muffled they mention something about "are the training torpedoes still aboard?" which is affirmed.
I'm guessing (really!!) that these were unarmed and used for safe practice.
The suggestion they could be "detonated electronically" might mean they were rigged with small self destruct charges to ensure they are destroyed and the parts sink.

Perhaps one of you swabbies can offer some input on this?

Come on lads, bags of swank!

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[–] Gatorman9 12 years ago

These things can get a way from you in a major-league hurry. You have to bear in mind the magnitude of the water entering the torpedo room through a hole almost two feet in diameter, and at a couple of atmospheres of sea pressure. The boat will take a terrific angle very quickly and suddenly you have a lot of downward momentum -- remember, the boat displaces several thousand tons -- that has to be neutralized. Controlling a casualty like this is a major effort and you actually drill for things analogous to this in simulators ashore. It could easily prove fatal. The bottom line is, this movie was far better technically advised than what you usually see.

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[–] Zanza8 10 years ago

This is why I love coming to IMDB. Sometimes you get really interesting information. Thanks for your post!

http://thinkingoutloud-descartes.blogspot.com/

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[–] Gatorman9 10 years ago

You're welcome.

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[–] Sprocket-man 8 years ago

In theory, a flooded forward compartment should not cause the boat to descend at that rate. It might tip downward. A boat can be caused to rise by releasing compressed air into the ballast tanks. (There are about a dozen compressed air tanks with 3000 psi air. At 3000 psi, a cubic foot of air is reduced to the size of a dime.)

Well, 14.7psi/3000psi = 0.0049 cu. ft/1.0 cu ft. So the air would occupy 0.0049 cu. ft (which is a cube about 0.170 ft on a side. )

A dime is about 0.00001197 cu ft. so the estimate is off by a factor of about 411. So it would be equal 8+ rolls of dimes (at 50 dimes per).

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[–] raf-33 10 years ago

Since no one in this thread seems interested in answering your questions I shall try.

Can one flooded compartment sink a boat? Yes, but not if they get the situation under control and just blowing the ballast tanks is unlikely to do it alone, they will instead try to drive to the surface. Since torpedo rooms are the likeliest compartments to flood and they are on either end of a boat this helps in that regard because full ahead or full reverse will drive the boat to the surface.

Was the compressed air supposed to drive the water back out? Yes, but not back through the torpedo tube, the raised air pressure just takes some strain off the pumps which are at ankle level, so they shift water more quickly and easily.

As submarine movies go this was a fairly accurate portrayal but as ever the submarine was more spacious than you would ever see in real life, even today. A whole compartment of racks for the marines to sleep in? In reality the marines would be scattered all over the sub sleeping anywhere from cupboards to the tops of washing machines.

Ya Kirk-loving Spocksucker!

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[–] Gatorman9 8 years ago

Yeah, they were in a world of hurt. As I looked at this I couldn't help thinking of it in terms of the boomers I'd been on, where the forward room is smaller in proportion to the whole ship, and is a self-contained compartment of its own (the boomer's biggest compartment is it vast missile compartment, and that alters the arithmetic substantially from a fast attack). Under those circumstances, as best as I recall, flooding that room doesn't rob you of all your reserve buoyancy, but you have a major trim problem (to put it mildly) and you can't drive yourself to the surface except on a major backing bell, if that were possible.

I had not thought about the effect of pressurizing the compartment to help out the pumps, but certainly you think that could help. One thing conspicuously missing from this sequence is the chief of the boat, and absent that at this point I can't remember if the captain gave any orders to pump anything or not.

As far as the gigantic empty berthing compartment just aft of the torpedo room where the marines were berthed that looks like pure Hollywood imagination (that boat even had to much empty space in the officer accommodations, as well) except to the extent that I had to wonder whether it didn't have some inspiration in the oversized one-off fast attack submarine TRITON, a white elephant almost as big as a boomer. Its hull was surely big enough to accommodate something like that, whether it was designed that way or not.

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[–] 8 years ago

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[–] thinkmcfly16 8 years ago

First, an open-through torpedo tube (TT) (both ends open) would flood a compartment effectively immediately. A modern TT is 533mm, or 21 inches in diameter. At any depth, the flooding rate is overwhelming, not like a Hollywood garden hose. Add to it, the noise would be deafening, and visibility would go to near zero just from the spraying everywhere. Finally, consider that the water is cold enough to place most normal humans in instant shock. A space will fill with water in mere moments.

Anyway, the space will fill up quickly, doing several things, adding weight to the boat at a tremendous rate, compressing the air quickly to the depth of the water, and putting most equipment in the space out of service. More on this later.

Now, if the compartment is immediately sealed from adjacent compartments, the boat might remain buoyant, IF: command and control, combined with training remain sufficient to "fight the boat", and the reserve bouyancy of the boat can overcome the added weight of water in the affected compartment. For many or most boats, a completely flooded torpedo compartment overwhelms a boat's reserve buoyancy, and she is going to the bottom. One must also consider that the torpedo compartment for most boats shares a common compartment with other facilities and spaces needed to effectively fight the boat, including the control spaces, including the diving station and steering and diving controls.

You can partly limit the volume water entering the affected compartment by pressurizing the affected compartment, but this will only hasted the death of those in the space, and the amount of water prevented entry is limited to the amount of available air, which is generally only useful at or close to the surface.

The short answer is generally that a double-ended open torpedo tube is a non-recoverable casualty.

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[–] Gatorman9 8 years ago

Yeah, they were in a world of hurt. But as as I looked at this I couldn't help thinking of it in terms of the boomers I'd been on, where the forward room is smaller in proportion to the whole ship, and is a self-contained compartment of its own which does not contain anything very far beyond torpedo room gear (unlike all the later later fast attacks, where the torpedo room is in the operations compartment; also, the boomer's biggest compartment is its vast missile compartment, which alters the arithmetic substantially from a fast attack). Under those circumstances, as best as I recall, flooding that room doesn't rob you of all your reserve buoyancy, but you have a major trim problem (to put it mildly) and you can't drive yourself to the surface except on a major backing bell, if that were possible.

As far as the gigantic empty berthing compartment just aft of the torpedo room where the marines were berthed that looks like pure Hollywood imagination (that boat even had to much empty space in the officer accommodations, as well) except to the extent that I had to wonder whether it didn't have some inspiration in the oversized one-off fast attack submarine TRITON, a white elephant almost as big as a boomer. Its hull was surely big enough to accommodate something like that, whether it was designed that way or not.

One thing I agreed with ion particular was the captain's statement that having both ends of the torpedo tube open at the same time is not possible under normal circumstances. It just isn't. I remember while qualifying n submarines wondering just what kind of casualty that could really be likely to occur could break the door interlock and permit that to happen.

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