Poseidon Adventure -- possible -- many questions?

Factual Questions
1

I was watching The Poseidon Adventure the other night and was wondering about how realistic the movie would be.

I know that the movie is based on a real-life WWII that almost capsized. The ship, however, did not end up capsizing. My questions are as follows:

[ul]
[li]Could a ship capsize as it did in TPA if a big enough wave hit it?[/li][li]Assuming people survived said capsizing (as they did in the movie), how realistic are their chances for survival?[/li][li]Could they travel upwards (downwards?) through the ship?[/li][li]Is the hull of a ship like really only an inch thick at the propeller shaft?[/li][li]How long would such a ship stay afloat when capsized?[/li][li]In the movie, the ship capsized shortly after midnight on New Year’s Day in the north Atlantic. In several scenes, the cast gets very wet. Shouldn’t the water have been cold enough to start the effects of hypotermia?[/li][li]Could an undersea quake make a tsunami in the middle of the ocean where there is no land nearby?[/li][li]Could a helicopter land on the hull of a capsized ship?[/li][li]Would the rescue crew have given up after finding just the one group? It certainly wasn’t more than twelve hours between the capsizing and the end of the movie.[/li][/ul]

Zev Steinhardt

2

Some nice points, a few new to me like the cold water issue.

Yes on capsizing. Bad design, bad ballast setup, oops.

Mostly no on tsunami. To get a steep enough wave to create something that would cause a problem requires a shallow bottom. There are places in the open ocean where there is a seamount not too far deep to make things interesting. (There’s one off the California coast surfers have been visiting lately.) But not in most of the ocean.

The first unrealistic aspect of PA is that the water pressure would have compressed the air significantly. Some interesting effects there, such as making fires a more serious issue. (Speaking of which, the fires would have burned nasty for a while and then smoldered as the oxygen was consumed. The smoke/gases from the fires would have been “bad” too.)

And then, when the hull was breached by the welders, whoosh city. Air, people, debris, and then eventually water, all going full tilt out the hole. Not survivable.

I have read stories about people surviving in capsizing hulls, but those seem quasi-ULish. Small boats, sure. Large ones??? In all that I recall, rescuers attempted to enter below the water line, rather than from above.

3

32 sailors were saved from the USS Oklahoma, which capsized at Pearl Harbor.

4

ftg answered the major points.

On some of the other points:

I believe that a few guys were rescued from the USS California after Pearl Harbor by cutting through the hull. (Although, the California was stuck in the harbor bottom, so the pressure issues ftg mentioned were not as big an issue. She was not going to sink any farther when the hull was ruptured (although the loss of air pressure might have doomed some men in other compartments).)

As long as there was air and they had the stamina, they could move through the ship in any direction. (I agree that the likelihood of a “perfect” capsizing that actually trapped any significant amount of air was infinitesimally small.) The closer they got to the hull, the more likely the ladders would have been “open” and, thus, capable of being climbed in reverse.

The ships I sailed had uniform hull measurements. My guess at the time I saw the movie was that the writer based that plot point on major warships where the armor belt is much thicker amidships. I am not a naval architect, however, and there may actually be ships where the hull is thicker amidships.

There are too many variables for me to guess at how long a capsized ship could stay afloat–even if it could do a 180 instead of simply heeling over far enough to take water and sink.

My memory of the location was different: I thought they were in the Mediterranean.

Any hull that is strong enough to support a 40,000 ton ship will support a four ton helicopter. (Although how the Poseidon ever got away from the dock using four tiny screws that were all smaller in diameter than a Westland Whirlwind is tall will forever remain a mystery.)

I don’t know about “giving up” after finding only one set of survivors. (In the book they are rescued by ships and there is an ironic comment noting that the people who headed for the bow were also rescued.) In the movie I only remember seeing the one Westland helicopter and the Whirlwind had a capacity of only ten people. (This, of course, is ignoring ftg’s point that once the hull was breached, there would be a huge gale of wind whistling out the hole until the ship disappeared.)

5

Well, that’s sort of a tautological question – if the wave is big enough, it’s big enough. The question is whether there ever could be a wave big enough to capsize an ocean liner without merely scuttling it.

[quote]
[li]Assuming people survived said capsizing (as they did in the movie), how realistic are their chances for survival?[/li][/quote]

** ftg** made a pretty good point. The ship would be like an upside-down bowl. It can float, so long as there is air trapped with nowhere to escape. Once you puncture the bowl, the air can get out, and the bowl (or ship) goes down.

[quote]
[li]Could they travel upwards (downwards?) through the ship?[/li][/quote]

Batman could, if he’s prepared.
Sorry.
Picture your house upside down. Above the stairs you might have a sloping ceiling, which then becomes a “floor.” It’s a ramp you could travel up, surface conditions permitting (i.e., it’s not to slippery or the ship is not tilted at too severe an angle.) Stair wells would cease to be stairs and become a series of ramps. However, if there was no corresponding slope above the stair to begin with, as with an open foyer, you’re out of luck.
I don’t see why people could not negotiate an upside-down structure, though obviously some avenues would be lost. If the ship has ladders, it’s a snap.

[quote]
[li]Is the hull of a ship like really only an inch thick at the propeller shaft?[/li][li]How long would such a ship stay afloat when capsized?[/li][/quote]

Don’t know on both counts.

[quote]
[li]In the movie, the ship capsized shortly after midnight on New Year’s Day in the north Atlantic. In several scenes, the cast gets very wet. Shouldn’t the water have been cold enough to start the effects of hypotermia?[/li][/quote]

You bet. And wearing soaking-wet clothes even when out of the water would perpetuate the effect. Obviously, the movie just ignored the problem – it was about getting out of an upside down ship, not about hypothermia. You don’t have to “freeze to death” to die of hypothermia. You just need to lose enough core heat. And, because the body would pull blood away from extremities – including the head and the brain – people should have been clumsier and mentally duller.

[quote]
[li]Could an undersea quake make a tsunami in the middle of the ocean where there is no land nearby?[/li][/quote]

I think someone else had a good answer.

[quote]
[li]Could a helicopter land on the hull of a capsized ship?[/li][/quote]

Doubt it, especially if the surface is curved and especially if the ship is bobbing in the water. I won’t say it’s impossible …

And it’s not just twelve hours. There’s got to be a morning after.

6

To expand on what Andy said, it’s not a matter of tautology, just physics. A sufficiently strong ship hull can withstand a large non-breaking wave without damage or capsizing. However, a breaking wave is another story. I forget where I read it, but in order for a wave to capsize a ship, it has to be higher than the beam of the ship. And out on the open sea, without an extremely strong wind, there’s very little to cause a wave to break. The reason tsunamis are so dangerous is because of what happens when the wave travels ashore and breaks. They’re not quite as destructive on the open sea.

[quote]
[ul][li]Is the hull of a ship like really only an inch thick at the propeller shaft?[/ul][/li][/quote]
Depends on too many factors to give a yes/no answer.

[quote]
[ul][li]How long would such a ship stay afloat when capsized?[/ul][/li][/quote]
Also dependent on a number of factors. Assuming a ship was hit with a big enough wave, it’s not so much the wave itself as it is the water getting inside the hull and changing the center of gravity. Ships are supposed to have enough watertight compartments to maximize stability even when partially flooded. Once enough water got inside and a big enough wave completely inverted the ship, it depends on the internal compartmentation. However, I think the downflooding would have been much faster than depicted in the movie.

[quote]
[ul][li]Could an undersea quake make a tsunami in the middle of the ocean where there is no land nearby?[/ul][/li][/quote]
See above. Not according to my understanding, but there may be other factors I’m leaving out.

7

Not quite. there are such things as rogue waves which can be as high as 100 feet which will be found in a set of normal sized waves out in the middle of the ocean. They usually occur during storms but not always.

Also in the book The Perfect Storm Sebastian Junger relates the anecdote of several Navy destroyers that were lost during WWII due to encounters with extremely high seas during typhoons in the Pacific theater.

8
  • Would the rescue crew have given up after finding just the one group? It certainly wasn’t more than twelve hours between the capsizing and the end of the movie.

If I remember right, wasn’t there a sequel to this movie where another group was in the ship? I don’t remember if they were rescued the same way.

9

Weren’t there sailors who survived the attack on Pearl Harbour but were trapped in capsized or partially sunk ships who couldn’t get out or be rescued? IIRC they communicated via tapping and some survived for days.

Let us also remember the Kursk. Some of the crew survived the initial disaster, only to suffocate.

10

How about the most overlooked plot hole, that there would have been no lights after the engines quit.

11

Thaaat’s right, that’s where I read the bit about wave height vs. ship beam. It’s a good non-mathmatical explanation of ship motion and design Thanks, Bogie!

12

You might also want to read the book - it goes into quite a lot of specifics on the engineering specs of the ship, and how the conditions were just right for it to be able to turn upside down. Naturally they don’t explain in as much detail in the movie.

13

Oh come now, Roddy McDowall had a throwaway line about emergency lights.

14

Yeah yeah, but if they used those lights it would have looked like The Blair Witch Project :smiley:

15

If I remember correctly the movie stated the ship was not properly ballasted, and after the wave hit the ship she was shown floating on her beam ends and then presumably rolled over.

16

Than the actors on The Poseidon Adventure? I thought they got that part down pretty good.

17

My comments on wave heights in the open sea only applied to tsunamis. Other conditions can indeed create giant waves. Wind being the most common. Resonance with shorelines another (my fav explanation for the wreck of the Ed. Fitzgerald).

18

My understanding of the Edmund Fitgerald tragedy is that the ship was at the apex of 3 storm sytems.