Korean Ferry Disaster

[Matthew]

Saw a news rerport last week. Divers have pulled out many bodies, with many still missing. They said a lot of the kids had signs of broken fingers, probably from trying to escape.

 

[Sac Arrow]

I have traveled on car-ferries in norway, sweden and across the british channel. On all the passages that went further than just crossing a fjord, commercial trucks were lashed down.

Over the years, a number of RoRo ferries have turned turtle, usually when operated in waters or in a manner they were not designed for (e.g. leaving port with the vehicle ramp open to have the breeze assist in clearing diesel fumes from the vehicle deck)

If that isn't a big red flag, I don't know what is. You shouldn't be able to turn a ship hard enough to capsize it in calm water.

 

[Henning]

Genoa, Nebraska? Sweet! Let me know when you'll be there. Ain't much of a town, but they do have a nice grass field. Practice up on your soft field landings, April showers have set in.

We'll bury the boat waterline deep in the middle of the rodeo grounds and let people wonder...

 

[Henning]

If that isn't a big red flag, I don't know what is. You shouldn't be able to turn a ship hard enough to capsize it in calm water.

My question is, "what was on the trucks?" If you have a top heavy overloaded gravel or coal truck and manage to tip it outboard, add a fair amount of free surface water in the bilge, and over it goes. Interesting thing is the entire crew has been arrested and the Prime Minister resigned over this. I think this and the SFO accident have awakened a vision into cultural shortcomings within Korean society.

 

[weilke]

If that isn't a big red flag, I don't know what is. You shouldn't be able to turn a ship hard enough to capsize it in calm water.

Each of these ships has operating and loading limitations, no different from an aircraft. If operated within their limitations, they are designed to withstand the weather in their area of operation. Many of the RoRo ferry disasters involved ships not being operated as designed.

 

[weilke]

Interesting thing is the entire crew has been arrested and the Prime Minister resigned over this.

Last time the south koreans rolled a RoRo ferry, the captain of the ship was sentenced to death .

 

[Sac Arrow]

Each of these ships has operating and loading limitations, no different from an aircraft. If operated within their limitations, they are designed to withstand the weather in their area of operation. Many of the RoRo ferry disasters involved ships not being operated as designed.

I'm no marine engineer obviously, but what constitutes "operating not as designed?" Most ships are generally not designed to run in to hard objects such as icebergs and other ships, and should be operated as such. I get that. But tipping over from a full hard rudder? Loading limits were grossly exceeded? Other ships don't seem to do that.

 

[Greg Bockelman]

But tipping over from a full hard rudder? Loading limits were grossly exceeded? Other ships don't seem to do that.

Maybe other ships were operated within their design limits.

 

[Clark1961]

Maybe other ships were operated within their design limits.

Or this ship was operated after significant design changes without new design limits. Acceptance testing after re-design/re-fit is always fun and expensive. Some folks don't like the expense...

 

[docmirror]

I'm no marine engineer obviously, but what constitutes "operating not as designed?" Most ships are generally not designed to run in to hard objects such as icebergs and other ships, and should be operated as such. I get that. But tipping over from a full hard rudder? Loading limits were grossly exceeded? Other ships don't seem to do that.

Put it this way, you are flying your flivver along at the top of the green arc in smooth air at max gross(minus take off fuel weight); You mash the rudder all the way to the stop. Will the plane hold together? I don't know, but sure as hell I'm not going to find out.

 

[weilke]

I'm no marine engineer obviously, but what constitutes "operating not as designed?" Most ships are generally not designed to run in to hard objects such as icebergs and other ships, and should be operated as such. I get that. But tipping over from a full hard rudder? Loading limits were grossly exceeded? Other ships don't seem to do that.

Are you allowed to kick alternating full left and right rudder in a air-carrier aircraft at maneuvering speed ?

 

[weilke]

Or this ship was operated after significant design changes without new design limits. Acceptance testing after re-design/re-fit is always fun and expensive. Some folks don't like the expense...

I believe that this ship was lengthened at least once.

 

[Jimmy cooper]

Nawwwww.....regulations not needed. They just hamper business people. Same thinking on Wall Street and we know how that turned out.

 

[Sac Arrow]

Are you allowed to kick alternating full left and right rudder in a air-carrier aircraft at maneuvering speed ?

I haven't a clue but I'd be surprised if you couldn't do so at cruising speed. I watched a documentary on the commissioning of the Ronald Reagan and they did just that.

 

[Clark1961]

I believe that this ship was lengthened at least once.

I used to translate shipyard and operational daily reports for management as part of a corporate engineering job (one of the more useless positions I've held). Based on what I read during that tenure, failure to test prior to returning to service will lead to a disaster sooner rather than later.

 

[docmirror]

I haven't a clue but I'd be surprised if you couldn't do so at cruising speed. I watched a documentary on the commissioning of the Ronald Reagan and they did just that.

Are you referring to the USS Ronald Reagan? As in - US navy ship? Comparing that to a floating tub like the Korean ferry?


ooooooooooooooooookkkkkkkkkkkkkkkkkk.........

 

[Sac Arrow]

Are you referring to the USS Ronald Reagan? As in - US navy ship? Comparing that to a floating tub like the Korean ferry?


ooooooooooooooooookkkkkkkkkkkkkkkkkk.........

Point being?

(I was responding to Weilke's question. Where in my post did I make any such comparison?)

 

[spiderweb]

Military pilots along with a sh*tload of others who engage in less than safe activities most all turn to black humor to relieve stress or to help them cope with catastrophic events in their lives.

Deal with it.

-John

Sure, when the stress levels rise, we all become racists, right? What's wrong with these people, gosh!

 

[docmirror]

Point being?

Jeez, thick much today?

US navy carrier <> Korean ferry.

 

[John Baker]

Sure, when the stress levels rise, we all become racists, right? What's wrong with these people, gosh!

One of the amazing things about our society is that we do not all think or act the same. Some of us do engage in unapproved thought or behaviour. I know this runs contrary to the social utopia being sought by the liberals, but it is true, we are not all perfect in our thoughts and our actions.

-John

 

[Matthew]

Jeez, thick much today?

US navy carrier <> Korean ferry.

Nope - not the same, but it does give you a pretty good idea of just how far over those things will roll in a hard turn. This is the Nimitz during sea trials.

 

[Clark1961]

Point being?

(I was responding to Weilke's question. Where in my post did I make any such comparison?)

Ummm, maybe re-read Weilke's question? Air-carrier not aircraft carrier

And no, full reversals on rudder are not a design parameter as some unfortunate folks found out when an Airbus precipitated on NY.

 

[MAKG1]

Point being?

(I was responding to Weilke's question. Where in my post did I make any such comparison?)

Actually, the question was about an air carrier (i.e., airliner), not an airCRAFT carrier.

And the reason he asked was that there was a crash caused by that action (AAL 587), related to a wake turbulence encounter.

It's an easy one to misread.

A better example would be, what happens when you descend just below Vne, then pull the elevator as hard and suddenly as you can, in a PA28?

 

[Sac Arrow]

Ummm, maybe re-read Weilke's question? Air-carrier not aircraft carrier

And no, full reversals on rudder are not a design parameter as some unfortunate folks found out when an Airbus precipitated on NY.

You're right, I completely misread his question.

But, I don't see the connection between aircraft and ship operation either. We aren't talking about aircraft, we're talking about ships. Kinda like why you wouldn't do something in a car because you shouldn't do it on a bicycle.

 

[Clark1961]

But, I don't see the connection between aircraft and ship operation either. We aren't talking about aircraft, we're talking about ships. Kinda like why you wouldn't do something in a car because you shouldn't do it on a bicycle.

I guess he was looking at operation outside design parameters and it might not be well known what the design parameters are (I know, horrible grammar).

As for the bicycle/car thing, could go either way, no?

 

[MAKG1]

You're right, I completely misread his question.

But, I don't see the connection between aircraft and ship operation either. We aren't talking about aircraft, we're talking about ships. Kinda like why you wouldn't do something in a car because you shouldn't do it on a bicycle.

You were objecting to operating limitations. All vehicles have them. Your car will understeer if you try to take a curve too fast. It isn't that rare for a load shift to overturn a tractor-trailer under similar conditions, especially if it's hauling liquid in large tanks.

 

[Sac Arrow]

Actually, the question was about an air carrier (i.e., airliner), not an airCRAFT carrier.

And the reason he asked was that there was a crash caused by that action (AAL 587), related to a wake turbulence encounter.

It's an easy one to misread.

A better example would be, what happens when you descend just below Vne, then pull the elevator as hard and suddenly as you can, in a PA28?

I guess he was looking at operation outside design parameters and it might not be well known what the design parameters are (I know, horrible grammar).

As for the bicycle/car thing, could go either way, no?

Okay, I get that I guess. But in the cited AAL 587 incident, isn't the tendency for the vertical stabilizer to break off something that one could consider a weakness of the Airbus 300?

 

[Sac Arrow]

You were objecting to operating limitations. All vehicles have them. Your car will understeer if you try to take a curve too fast. It isn't that rare for a load shift to overturn a tractor-trailer under similar conditions, especially if it's hauling liquid in large tanks.

I wasn't objecting to them in general. I was just unaware that steering rate could be a limitation in ships.

 

[docmirror]

Okay, I get that I guess. But in the cited AAL 587 incident, isn't the tendency for the vertical stabilizer to break off something that one could consider a weakness of the Airbus 300?

Again, no. The design loads were consistent with the design loads of similar aircraft at the time of design. It could handle full deflection in one direction at maneuvering speed but not abrupt reversals, which is what the co-pilot did. In short - he broke it off by mashing the pedals.

 

[Sac Arrow]

Again, no. The design loads were consistent with the design loads of similar aircraft at the time of design. It could handle full deflection in one direction at maneuvering speed but not abrupt reversals, which is what the co-pilot did. In short - he broke it off by mashing the pedals.

Well alright then.

 

[Clark1961]

Again, no. The design loads were consistent with the design loads of similar aircraft at the time of design. It could handle full deflection in one direction at maneuvering speed but not abrupt reversals, which is what the co-pilot did. In short - he broke it off by mashing the pedals.

None of which precludes the conclusion that it was a point of design weakness. It met the specification but it was still not resistant to the loads which actually occurred.

 

[docmirror]

None of which precludes the conclusion that it was a point of design weakness. It met the specification but it was still not resistant to the loads which actually occurred.

Well, that sounds pretty nice; 'loads which actually occurred'. Like the loads fell out of the sky, and smote this vert stabilizer. The loads were the result of a person deflecting the rudder pedals. If the pilot would have put his feet flat on the floor, and kept the wings level with the yoke, the plane would have been just fine. But - he didn't, and it wasn't.

Every system is a compromise. The vert stabilizer could have been designed to accept repeated, abrupt opposite full deflection at maneuvering speeds. Of course, it would have weighed double, the CG would be completely different, and the plane would have other less robust systems as a result of beefing up the stabilizer, but sure - we could design it so that any ham-footed crap-flinger can sit in the cockpit and stomp out a Snoop-Dog rap song on the pedals. No prob.

 

[Fearless Tower]

Are you allowed to kick alternating full left and right rudder in a air-carrier aircraft at maneuvering speed ?

IF you go hard rudder and immediately shift it, not much will happen in a carrier. Newton stuff. Lot of mass to move and the ship takes a little while to respond to the rudder. It is actually a material check that is required for INSURV (congressionally mandated ship inspection done roughly every 5 years).

If you hold hard rudder for more than a few seconds, then you will get a pretty good heel. With a CVN/LHD, or any ship with a flight deck, the big limit on using rudder is aircraft on deck. You don't want to use large rudder inputs with aircraft unsecured for fear of them hitting each other. When USS JOHN F KENNEDY collided with a dhow back in 2004, the turn they made trying to avoid the vessel resulted in at least one F-14 sliding sideways into another aircraft.

 

[Fearless Tower]

I haven't a clue but I'd be surprised if you couldn't do so at cruising speed. I watched a documentary on the commissioning of the Ronald Reagan and they did just that.

All depends on how well the bird farm secures the birds.

 

[Fearless Tower]

I wasn't objecting to them in general. I was just unaware that steering rate could be a limitation in ships.

Of all the ships I have sailed on in both the merchant marine and Navy, the only steering/rudder limits I have ever seen were a function of other issues like aircraft or wardroom china. They were not related to the safety of the ship itself.

 

[Clark1961]

Well, that sounds pretty nice; 'loads which actually occurred'. Like the loads fell out of the sky, and smote this vert stabilizer. The loads were the result of a person deflecting the rudder pedals. If the pilot would have put his feet flat on the floor, and kept the wings level with the yoke, the plane would have been just fine. But - he didn't, and it wasn't.

Every system is a compromise. The vert stabilizer could have been designed to accept repeated, abrupt opposite full deflection at maneuvering speeds. Of course, it would have weighed double, the CG would be completely different, and the plane would have other less robust systems as a result of beefing up the stabilizer, but sure - we could design it so that any ham-footed crap-flinger can sit in the cockpit and stomp out a Snoop-Dog rap song on the pedals. No prob.

You exaggerate quite well. I commend you on your ability to launch into un-called-for hyperbole at a moments notice. Well done.

 

[Greg Bockelman]

You exaggerate quite well. I commend you on your ability to launch into un-called-for hyperbole at a moments notice. Well done.

Where was the exaggeration and what was the hyperbole?

 

[Clark1961]

Where was the exaggeration and what was the hyperbole?

"Of course, it would have weighed double, the CG would be completely different, and the plane would have other less robust systems as a result of beefing up the stabilizer, but sure - we could design it so that any ham-footed crap-flinger can sit in the cockpit and stomp out a Snoop-Dog rap song on the pedals. No prob."

 

[docmirror]

You exaggerate quite well. I commend you on your ability to launch into un-called-for hyperbole at a moments notice. Well done.

Thanks. Wondering if hyperbole is ever 'called for'?

When you said; "point of design weakness" it's one of those engineer-speak terms that non-engineers use to deflect blame from the operator, like the ham-footed pilot.

i.e. "I pitched this baseball at the plate glass window and it shattered. Therefore, the plate glass window exhibited a point of design weakness. Get Jerry to look into that."

 

[docmirror]

"Of course, it would have weighed double, pretty close, no sale the CG would be completely different, Oh heck yes, no saleand the plane would have other less robust systems as a result of beefing up the stabilizer, yes again, investigate 'weak link design' no salebut sure - we could design it so that any ham-footed crap-flinger can sit in the cockpit and stomp out a Snoop-Dog rap song on the pedals. hyperbole; check No prob."

Sorry.