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tony873004
2007-Nov-23, 09:32 PM
An expidition cruise ship is sinking near Antarctica. This ship, the Explorer, is almost identical to the Clipper Adventurer, which I was on 3 years ago in Antarctica.

After striking an iceberg, water is coming in through a hole the size of a fist, according to news reports. This has got me wondering. Are there simple ways to prevent such a small hole from causing such a majestic ship from sinking?

When I was on the Clipper Adventurer, I marveled at the water-tight doors. They can obviously isolate the damaged section. And unlike Titanic, which was gashed across several sections, a fist-sized hole implies only one section was breached.

Why isn't it possible to stock airbags in all underwater sections? In the event of a breach, the people get evacuated from that section, the section gets sealed off and the airbags get deployed, filling large amounts of the empty space leaving less room for water.

Or perhaps, since it seems like it will take about a day for the ship to sink, divers can plug the hole. With the pressure of the water moving into the ship, it seems all you would have to do is place a large blanket over the hole and the pressure would hold it in place until a more permanant solution could be devised.

My ideas are too simple. There's got to be a good reason measures like this are not taken.

Noclevername
2007-Nov-23, 09:39 PM
Many modern large ships use means such as compartmentation and multiple hulls. But although air is cheap, pumps to push it around are expensive, and watertight airbags strong enough to withstand even moderate water pressue are probably also fairly pricey, especially if they are large enough to fill a ship's compartment. The weight and bulk of bags, pumps or compresssed-gas tanks would also cut into available cargo space.

MentalAvenger
2007-Nov-23, 10:22 PM
Water pressure depends only on the depth and density of the water. At 28 feet, water pressure is about 27psi, only about double the atmospheric pressure at sea level. The Explorer of the Seas has a draft of about 28 feet. That means that even a hole at the very bottom would experience a pressure of only about 27psi. Halfway up the side, it would only be about 21psi. That can be produced with a high pressure blower. The main problem with airbags would be withstanding punctures from sharp objects.

I have seen rescue units lifting entire automobiles, even trucks, with airbags and a blower.

One of the problems with the Titanic is that their watertight compartments did not go all the way up. When the water filled the forward compartments, the bow settled, and the water simply ran over the top of the other compartments, one at a time, until the entire ship filled.

KaiYeves
2007-Nov-23, 10:22 PM
Are the people on the Explorer okay?

MentalAvenger
2007-Nov-23, 10:28 PM
The ship has been abandoned, and all passengers and crew have been rescued. “The Little Red Ship” has been a favorite of a lot of people.

MentalAvenger
2007-Nov-23, 10:31 PM
http://www.panoviews.com/images/MV_Explorer.jpg

KaiYeves
2007-Nov-23, 10:32 PM
The ship has been abandoned, and all passengers and crew have been rescued. “The Little Red Ship” has been a favorite of a lot of people.
This is a good thing.

MentalAvenger
2007-Nov-23, 10:35 PM
http://www.bloomberg.com/apps/data?pid=avimage&iid=ib.mhBGrv9vE

Noclevername
2007-Nov-23, 10:38 PM
From the pic, it's smaller than I thought it was. The airbag idea would maybe be workable on a very large ship, but it wouldn't scale down very well.

tony873004
2007-Nov-23, 10:47 PM
I've only read that it is sinking, not that it has sank yet.

Evacuation was probably easy compared to a non-expidition ship. When I was on the almost-identical Clipper Adventurer, we would abandon ship twice a day, as all the passengers borded zodiacs for excursions to the various islands. It only took about 35 minutes to empty the ship of passengers in a non-emergency. (of course this didn't count the crew and staff).

I'm grateful everyone is ok. But having travelled on one of these majestic ships, I can't help but feel sad that the ship will be lost.

As far as the airbag idea, they're very small when they're not inflated. And they can be strong too. Think of the Mars rovers. When the airbags inflated, it was nearly 2 stories tall, and it bounced for nearly 1 kilometer over the sharp Martian rocks. Having multiple airbags in each compartment would provide redundancy incase some were damaged. If every spare nook (and there's lots of them) contained an airbag assembly, I imagine the inflated bags would displace enough volume to keep the ship from sinking.

Here's some pictures from my trip to Antarctica abord the nearly-identical Clipper Adventurer: http://www.orbitsimulator.com/Antarctica/1024page1.html

Noclevername
2007-Nov-23, 10:57 PM
As far as the airbag idea, they're very small when they're not inflated. And they can be strong too. Think of the Mars rovers. When the airbags inflated, it was nearly 2 stories tall, and it bounced for nearly 1 kilometer over the sharp Martian rocks. Having multiple airbags in each compartment would provide redundancy incase some were damaged. If every spare nook (and there's lots of them) contained an airbag assembly, I imagine the inflated bags would displace enough volume to keep the ship from sinking.


And they would probably cost more than the ship itself. It took NASA money to make the Mars Rover landing bags.

tony873004
2007-Nov-23, 11:07 PM
I'm not suggesting using identical airbags as the Mars rovers. I only mention them because they're the best example to show that airbags can inflate to a large size from a small unit, and be strong. Anything is expensive per unit if your cost of designing it is spread over only 2 units. Realistically, I would expect mass-production a generic shoe-box sized airbag that could be bolted anywhere there was an extra quarter cubic foot, rather than all the engineering costs being spent on producing a single airbag system. With redundancy, failure in an individual unit is an option NASA didn't have.

Noclevername
2007-Nov-23, 11:15 PM
I'm not suggesting using identical airbags as the Mars rovers. I only mention them because they're the best example to show that airbags can inflate to a large size from a small unit, and be strong. Anything is expensive per unit if your cost of designing it is spread over only 2 units. Realistically, I would expect mass-production a generic shoe-box sized airbag that could be bolted anywhere there was an extra quarter cubic foot, rather than all the engineering costs being spent on producing a single airbag system. With redundancy, failure in an individual unit is an option NASA didn't have.

A shoebox-sized unit would need to include both compressed gas container and a sufficiently sturdy waterproof bag. Unless I miss my guess, it wouldn't be able to inflate enough to make much difference in volume in a flooding ship. And it may not match the multimillion dollar price tag of the famous landing bags, but it still wouldn't be cheap.

Does anyone know the standards for compressed-gas tanks-- how much volume they can hold and production price?

tony873004
2007-Nov-23, 11:24 PM
Scuba tanks are about 15 liters of 3000psi. That's a few thousand liters of 1 bar air.

grant hutchison
2007-Nov-23, 11:47 PM
I was a little surprised to see that the life-boats were open, rather than the closed variety which can roll 360 degrees without shipping water.
If the ship had got into trouble during a storm in the Drake Passage, things might have been very unpleasant indeed.

Grant Hutchison

Delvo
2007-Nov-23, 11:51 PM
Nevermind the bags; why isn't compartmentization saving the ship from such a small hole?

tony873004
2007-Nov-24, 12:05 AM
I was a little surprised to see that the life-boats were open, rather than the closed variety which can roll 360 degrees without shipping water.
If the ship had got into trouble during a storm in the Drake Passage, things might have been very unpleasant indeed.

Grant Hutchison
That surprised me too. When I first saw the picture, I thought it was the same ship I was on, only repainted and renamed. But there were enough subtle differences, including the lifeboats that convinced me otherwise. Here's a pic of the Clipper, with the enclosed lifeboats
http://www.orbitsimulator.com/Antarctica/1024fs_IMG_69901024.jpg

MG1962A
2007-Nov-24, 12:06 AM
Nevermind the bags; why isn't compartmentization saving the ship from such a small hole?

Because according to its last Lloyds inspection, they didn't work - In fact it seems it failed about five other catagories. So what it is doing down there, God only knows. Also being built in 69' It suffers from other issues

tony873004
2007-Nov-24, 12:23 AM
Because according to its last Lloyds inspection, they didn't work - In fact it seems it failed about five other catagories. So what it is doing down there, God only knows. Also being built in 69' It suffers from other issues

That's scary. When I was on the ship, I felt safe. The enclosed life boats, and the water tight doors (I think they even had warning lights). I just assumed they worked. Now I wonder.

We even bashed a lot of ice intentionally. The ship was made to break through ice. I thought of it as unsinkable. (I guess that's bad luck). The news reports say the crew was claiming it wasn't an iceberg, but submerged ice. WTF?! What is submerged ice? The Clipper had an open bridge policy. Their radar was awesome. You could spot small iceberge beyond the horizon, and then use binoculars to watch them pop above the horizon.

When we crossed the Drake, the crew was referring to it as Drake's Lake. They said it was often glass-smooth this time of year, but had some horror stories of 100 foot swells to tell too. Grant's right. I wouldn't want to face those swells in a glorified row boat.

grant hutchison
2007-Nov-24, 12:39 AM
The news reports say the crew was claiming it wasn't an iceberg, but submerged ice. WTF?! What is submerged ice?I thought it was the same thing as anchor ice. You get a supercooled flow coming out from under shore ice, and it builds layers of crystals on any handy nuclei of crystallization: including the sea bottom. Builds up in plates and lumps and fronds in shallow Antarctic water, down to to 10 or 20m depth. Doesn't seem like the sort of thing that would get big enough and solid enough to hole an ice-strengthened hull, though.

Grant Hutchison

danscope
2007-Nov-24, 04:59 AM
Hi, Simple fact: Water pressure at 100 feet is 44 PSI. At 50 feet, 22PSI.
At 25 feet....11 PSI. It doesn't take a lot of pressure to bag a leak .
A small puncture can be stopped with water and ice barrier( like you use on a roof..) Spread it on a piee of plywood, and put it over the hole. Water pressure
squishes it against the hull. Shoot it in with a hard pin. Done. But, it's the sea state a diver has to live with ....in the arctic.
Sounds like fun.
Dan

tony873004
2007-Nov-24, 08:44 AM
That was the 2nd of my my two options. Send a diver down and stick something in or over the hole. They make drysuits for arctic diving. Many on the expedition crew are experienced divers.

The drain in my washroom sink is about 1/3 of the diameter of a fist. It only takes a little bit of laundry lint to completely block it (of course it has a screen which helps). Too much paper can back up a toilet. That's about a fist-sized hole.

These ships cost (just guessing) in the 10s of millions of dollars. I find it hard to believe that there isn't some simple solution to prevent a fist-sized hole from sinking it and endangering the lives of hundreds of people.

Van Rijn
2007-Nov-24, 09:15 AM
These ships cost (just guessing) in the 10s of millions of dollars. I find it hard to believe that there isn't some simple solution to prevent a fist-sized hole from sinking it and endangering the lives of hundreds of people.

There might be more to it than that. I did a news search and found this:

http://www.sltrib.com/ci_7546959

From there:

The company that owned the vessel, G.A.P. Adventures of Toronto, initially described the damage as a ''fist-size hole,'' but the Argentine navy later told The Associated Press it observed ''significant'' damage to the hull.

It has a double hull, so even if the inner hull has a fist sized hole, it might have significantly more external damage. Depending on damage, it might be hard to get a good seal. Another article said they were trying to keep it from sinking using pumps. Perhaps they'll manage, but they aren't going to take chances with the passengers.

Jens
2007-Nov-24, 12:04 PM
I was suspicious from the start about the "fist sized hole." It seemed like damage control, I mean PR damage control. I think a ship striking an iceberg would probably receive more damage.

Remember Monty Python, "It's just a flesh wound."

01101001
2007-Nov-24, 02:34 PM
Perhaps they'll manage, but they aren't going to take chances with the passengers.

I heard it sank 13 hours ago. The news report than was that though the hole was said to be fist-sized there were also unconfirmed reports of a crack, and multiple compartments flooding.

I suspect the answer to the puzzle of the unpluggable small hole is that there wasn't a small hole to plug.

Like: Melbourne Herald Sun: Antarctic ship hits iceberg (http://www.news.com.au/heraldsun/story/0,21985,22813529-662,00.html)


"The ship encountered ice and the result was a hole about the size of a fist, and a crack through which water began leaking in," said Susan Hayes, GAP's vice-president of marketing.

Or: Toronto Star: `Small hole' wouldn't sink well-designed ship: Professor (http://www.thestar.com/News/article/279494)


"My gut feeling is there must be more than what we're being told because one small hole is not going to sink a well-designed ship," said University of British Columbia professor emeritus Sander Calisal.

"The flooding might have caused an electrical circuitry problem so the pumps didn't work properly. Something additional must've happened because a small hole won't cause such damage."

JustAFriend
2007-Nov-24, 03:50 PM
Its fairly easy to make an unsinkable ship.

The problem is cost; both up-front and liability.

Its far easier to just insure the ship and shove it down the launching ramp...

KaiYeves
2007-Nov-24, 06:04 PM
This thread made me think of a certain funny quote:
Is there any such thing as an unsinkable ship?
"Yeah, one that's already sunk." -Robert Ballard

MentalAvenger
2007-Nov-24, 06:14 PM
Hi, Simple fact: Water pressure at 100 feet is 44 PSI. At 50 feet, 22PSI.
At 25 feet....11 PSI. Not exactly. Water pressure in salt water at 100 feet is 58.0487psi, at 50 feet it is 36.3723psi, at 25 feet it is 25.5341psi. Notice it is non-linear. Here is a handy calculator (http://www.gazza.co.nz/waterpressure.html)

Van Rijn
2007-Nov-24, 11:09 PM
I heard it sank 13 hours ago. The news report than was that though the hole was said to be fist-sized there were also unconfirmed reports of a crack, and multiple compartments flooding.

I suspect the answer to the puzzle of the unpluggable small hole is that there wasn't a small hole to plug.


Heh. The situation, and the news reports, "evolved quickly" as they say. Last night I saw articles that were still talking about about it possibly being saved, and this morning the newspaper said it had sank.

JohnD
2007-Nov-24, 11:19 PM
From the pic, it's smaller than I thought it was. The airbag idea would maybe be workable on a very large ship, but it wouldn't scale down very well.

Every small sailing dinghy has either closed compartments or airbags, so that it can't sink if it capsizes. How much smaller before it doesn't scale down?

I think this is an excellent idea. And there is no need for compressors or compressed air cylcinders - pyrotechnics to inflate, like a car's crash bag , are very light indeed for the amount of gas they produce. Some of that produced when a car's bag fires will be hot, and cooling will deflate the bag, but there are many other chemical means of producing large quatities of gas. Chalk and an acid, for instance.

John

mugaliens
2007-Nov-24, 11:24 PM
Many modern large ships use means such as compartmentation and multiple hulls. But although air is cheap, pumps to push it around are expensive, and watertight airbags strong enough to withstand even moderate water pressue are probably also fairly pricey, especially if they are large enough to fill a ship's compartment. The weight and bulk of bags, pumps or compresssed-gas tanks would also cut into available cargo space.

Not as much as you think. A 72 cubic foot scuba tank, complete with it's full complement of compressed air hardly weighed much more than the empty tank itself. If the gas used was helium, instead of air (mostly nitrogen), the weight would be negligible compared to the system. Design bags to inflate to 80% of the room's space.

Would it work?

Yes. It would prevent sinking, provided the bags were durable.

A very good idea, Noclevername.

You should be highly commended.

- Mugs.

PS: From a cost-analysis perspective, there's some doubt that it would cross the cost barrier. That is, even though the cost of the ship is measured in millions, if not billions of dollars, the chance of a catostrophic collision is very very slight, given the millions of man-hour-miles traversed, and the added cost of the anti-sinking system seems to be about the same as the very slight risk of sinking.

Believe it or not, most senior ship engineers run through these calculations before they sign on the bottom line. Evidently, the other systems are more expensive than the statistical liklihood of complete ship's failure.

MentalAvenger
2007-Nov-25, 12:37 AM
Due to the shape of the hull, compared to the shape of various compartments, there can be voids that can be filled with closed cell foam. It seems that, although usable space aboard a ship is a premium, there should be enough space in the unusable voids to provide enough foam to at least keep a ship just afloat.

MentalAvenger
2007-Nov-25, 12:40 AM
Yes. It would prevent sinking, provided the bags were durable.

A very good idea, Noclevername.

You should be highly commended. Uh………actually, it was tony873004’s suggestion. Noclevername was arguing against it.

pghnative
2007-Nov-25, 12:57 AM
Hi, Simple fact: Water pressure at 100 feet is 44 PSI. At 50 feet, 22PSI.
At 25 feet....11 PSI.Not exactly. Water pressure in salt water at 100 feet is 58.0487psi, at 50 feet it is 36.3723psi, at 25 feet it is 25.5341psi. Notice it is non-linear. Here is a handy calculator (http://www.gazza.co.nz/waterpressure.html)
Umm....that's extremely linear. y = 14.7 + 0.44* X

MentalAvenger
2007-Nov-25, 01:08 AM
:shhh:

Noclevername
2007-Nov-25, 01:50 AM
And as with any active system, there's the question of complexity. How much to add all the sensors, wiring, power sources, etc., needed to activate the doodads? How high a failure rate? How would it effect insurance? And so on.

Kaptain K
2007-Nov-25, 02:35 AM
The ship was double-hulled. Why wasn't the space between the hulls filled with foam?

Captain Kidd
2007-Nov-25, 03:31 AM
Well, looks like she sank. Hmm, one news article mentions reports of flooding in the sanitary system. That might explain how water was able to spread throughout the ship. Maybe (just a wild thought) the isolation valves didn't work as designed (or were not closed if they weren't check valves) and water thus found a path throughout the ship.

tony873004, some of your comments seem to suggest that you think the MS Explorer and the Clipper Adventurer are the same type of ships or very similar (and thus are now worried about you trip on her). To put you at ease, the Clipper is 4364 tons and the Explorer 2398 tons. Further, the Clipper is about 84 feet longer (330 ft versus 248 ft) Oh and the Explorer drafts 14.7 ft not 28 ft, so even less water pressure than at the 25 feet people are using. So you were on a bigger and newer ship, plus a different company with probably different maintenance requirements.

Double hulled and ice hardened, she really took a hit. I'm having difficulty finding anything on what Llyod's ice rating specifications are.

tony873004
2007-Nov-25, 05:16 AM
Thanks. I was just going on the pictures without looking at the specs. They sure look the same except for the paint job. One web site had pictures of the interior of the Explorer. The dining hall, the lecture hall and the social lounges all looked familiar. The Explorer was even doing the same route that we did: Ushuaia, Falklands, South Gerogia...

Glad to know I was safer than I thought.

The expidition I was on was run by Linblad. They owned the Explorer until 3 years ago according to an article I read. Maybe they got rid of her for a reason.

It's still a little unnerving to realize that submerged ice exists. I had never heard of it until Grant's description. Based on his description I'd imagine it could only occur in shallow water. But they seemed to be in open ocean when they struck ice. If it was shallow enough for submerged ice they should have avoided the area, or perhaps travelled slower.

On our trip we'd hit ice a lot, but floating ice. We'd be sitting at dinner and the whole ship would shake from a collision. The passengers would all turn white with fear, and start talking about the Titanic, while the crew tried to contain their amusement at our reactions. I think they realized it made us order more drinks :)

KLA2
2007-Nov-25, 07:37 PM
The ship may have struck a drifting mine or torpedo. Thousands of these things unaccounted for after two world wars. Some eventually break free of their moorings and drift with currents. An account I read (Toronto Star) from a passenger reports the usual crunching of ice, then a loud "bang".

Mister Earl
2007-Nov-26, 02:31 PM
Unsinkable ship? Low production costs? Send out a call to the Pykrete (http://en.wikipedia.org/wiki/Pykrete) man!

A ship made with this could be sawn in half and still float.

MentalAvenger
2007-Nov-26, 04:28 PM
An account I read (Toronto Star) from a passenger reports the usual crunching of ice, then a loud "bang".That “bang” was Captain Smith banging his head on the bulkhead when he realized he hit an iceberg.

korjik
2007-Nov-26, 04:49 PM
Unsinkable ship? Low production costs? Send out a call to the Pykrete (http://en.wikipedia.org/wiki/Pykrete) man!

A ship made with this could be sawn in half and still float.

Technically, it could be broken into bite sized chunks and at least the hull and superstructure would still float :)

That is really some amazing stuff

danscope
2007-Nov-26, 06:59 PM
It would appear that there is a lesson here: " It is still fool hardy to
make way through an ice field in anything less than a certified ice breaker ".
It is also clearly absurd to speed through an icefield 'IN THE DARK' !.
Arrogance is a malevolent shipmate. Their examples litter the ocean floor.

Best regards,
Dan

KaiYeves
2007-Nov-26, 09:55 PM
www.badarchaeology.net -Jesus's mount was not a velociraptor.
Would that technicaly be paleontology and not archeology?

Ilya
2007-Nov-27, 02:49 AM
Steel can not float! All steel ships are a HOAX!

Noclevername
2007-Nov-27, 03:25 AM
Would that technicaly be paleontology and not archeology?

For Creationists, those are the same thing. Being that man was made only one day after the first animals and all.

danscope
2007-Nov-27, 03:55 AM
Steel can not float! All steel ships are a HOAX!

" Sir, this ship is made from iron. I assure you that it can sink."
.......... a young Mr. Andrews , an engineer associated with a ship
of the White Star Line .

Dan

HenrikOlsen
2007-Nov-27, 07:27 AM
Would that technicaly be paleontology and not archeology?
Paleontheology

Mister Earl
2007-Nov-27, 04:31 PM
Would that technicaly be paleontology and not archeology?

Aye, if it was bones ye be lookin' at. But, if we're talking about pottery and old papyrus scrolls, then Archeology :)

Mister Earl
2007-Nov-27, 04:32 PM
Hrm. If wood shavings suspended in a block of ice make it that strong, I wonder how good shredded velcro would do in ice...

* scribbles up a patent application *

Or wait! Shredded isolation foam! Freezing the mix would be tough, but once done...

* Flips pencil over, wears out eraser *

korjik
2007-Nov-27, 04:38 PM
Steel can not float! All steel ships are a HOAX!

Since fire cant melt iron anyway, steel ships have always been a hoax.

:)

crosscountry
2007-Nov-28, 03:01 PM
There might be more to it than that. I did a news search and found this:

http://www.sltrib.com/ci_7546959

From there:

The company that owned the vessel, G.A.P. Adventures of Toronto, initially described the damage as a ''fist-size hole,'' but the Argentine navy later told The Associated Press it observed ''significant'' damage to the hull.

It has a double hull, so even if the inner hull has a fist sized hole, it might have significantly more external damage. Depending on damage, it might be hard to get a good seal. Another article said they were trying to keep it from sinking using pumps. Perhaps they'll manage, but they aren't going to take chances with the passengers.

Speaking of the value of these ships, I wonder if they weren't looking to upgrade on the insurance money. The accident might be real, but their attempts to save the ship may not be.