Some speculation about the stability seams to be a bit off the mark.
The ship will have to have been designed and built to meet requirements. I can’t recall exactly what they all are.
As a general rule most passenger ships tend to have smaller GM intentionally so they are a bit tender making them roll slowly and gently and be a bit more comfortable. large GMs tend to be avoided due to a stiff ship having a fast uncomfortable roll.
Modern Cruise Ships have a great deal of machinery spread over several compartments down low the center of Gravity of this machinery or g contributes to a Low overall Center of Gravity G. In addition to the machinery there are lots of tanks for ballast, FW Grey water, Fuel which tend to be very low often in double bottoms again low g contributing to a low G. This being countered by the high decks furniture and even passengers. I believe the allowance per passenger has been increased.
One of the reasons the ship may have had to slow down might have been to avoid excessive pounding or panting. Modern cruise ships tend to have very wide flared bows. Hitting big seas at significant speeds could cause a lot of damage. The shock from hitting such seas could be a lot more alarming than rolling. In addition to pounding Screws could be coming out the water causing engines to over-sped all adding to discomfort but not necessarily the ship being in actual peril.
Of course if you are a farmer from Iowa who has never seen the ocean before. All this about stability might not be very reassuring.
The old ocean liners could handle much more. not so much because they were more stable. But because they were built to go across the N Atlantic year round. Much heavier steel plating, Framing and finer lines to cut through waves. And furniture fastened down.
The New Queens have much finer lines than most cruise ships. Boats are higher, plating thicker, framing ect.
If you ever get the chance or can somehow wangle the chance to go to MARIN for a seakeeping test, do it.
Top shelf institute, and lots of resources if you want to learn more about the topics - particularly ship design and sea keeping response. Sounds boring, but you can really understand it, just from sea going experience.
Seeing the tests proving the anticipated results is really a joy, and almost edumactional for the susceptible to ler’nin types.
They have done lots of research on passenger comfort.
One thing we learned is to consider the roll period you are designing to, compared to the prevalent wave period in the intended operating area.
Get it wrong and the pax ain’t gonna be likin it … stabilizers or not.
The test tanks they have for testing TLP / anchoring systems and another for propellers are unbelieveable as well.
You want to talk about an investment becoming an economic engine …
MARIN Institute is the best example I think one can find for the positive effects guv’vermint spending.
[QUOTE=catherder;178783]That Cruiselaw site tends to play into the ignorance of the general public. The guy who runs it is a lawyer. I do enjoy some of his posts, but he plays up the hyperbole. He tends to blame the cruise lines for every single thing that happens to passengers, especially norovirus outbreaks and pax who fall overboard. Have you ever walked around on a cruise ship? It’s hard as hell to fall overboard unless you’re trying. Or shit faced. Of course, he makes his money from lawsuit winnings so there’s his motivation.[/QUOTE]
Yeah, over on FB, he chastised my comment about passengers expecting a hotel like stay while at sea, saying that it is the onus of the Cruise Line to provide a calm experience. . . off of the Graveyard of the Atlantic? Passengers are the last people who should be giving descriptions of what it was like. . . 30 degrees? Really? Thought they were going to die? Oh, but lookie, free minibar and football is on. . . . they ought to try that trip in the middle of a norther in a 160 foot tugboat towing an SL-7. . . . .THEN they would find out what the life jacket is REALLY used for. Except they don’t have bunks in those cabins. . . .
“The Coast Guard says it will also be participating in an investigation that will help determine if there are any contributing causal factors or lessons learned after the Anthem of the Seas, with more than 6,000 people on board, sailed directly into a forecasted storm over the weekend.”
The causal factor was no one had the brains or the sack to say don’t go into that shit. The lesson should have been learned hundreds of years ago. You go into (known) shitty weather and you get your ass kicked. Bounty? El Faro?
How many more is it going to take to get the picture?
I listened to the captain’s talk posted above from beginning to end.
If a ship spends a lot of time working in areas where the weather doesn’t change much from day and when it does change its a tropical cyclone, a mindset develops that if there is a weather system that requires attention the information will be in the form of a very strong “signal”. It’s really difficult to avoid news of systems forming in the tropics so the mindset of the crew is that they don’t have to put much effort into seeking out weather information.
I see this myself as the ship moves from having spend a long time in areas of the trades to areas where frontal systems and low pressure dominate the weather. When the ship moves into an area of bad weather the operational situation changes, the mates as well as the captain have to change their mindset, shift their attention and have a process of constantly evaluating weather information.
Actually to be effective the process of evaluating weather information on a continuous basis has to have been in place before the ship’s situation changes and only needs to be rebooted to reflect the change in the ship’s status with regards to the weather.
Alaskan mariners, who have been discussed here more then once, will not understand this as they are in “it’s not if but when” mode all the time.
[QUOTE=Kennebec Captain;178938]I listened to the captain’s talk posted above from beginning to end.
If a ship spends a lot of time working in areas where the weather doesn’t change much from day and when it does change its a tropical cyclone, a mindset develops that if there is a weather system that requires attention the information will be in the form of a very strong “signal”. It’s really difficult to avoid news of systems forming in the tropics so the mindset of the crew is that they don’t have to put much effort into seeking out weather information.
I see this myself as the ship moves from having spend a long time in areas of the trades to areas where frontal systems and low pressure dominate the weather. When the ship moves into an area of bad weather the operational situation changes, the mates as well as the captain have to change their mindset, shift their attention and have a process of constantly evaluating weather information.
Actually to be effective the process of evaluating weather information on a continuous basis has to have been in place before the ship’s situation changes and only needs to be rebooted to reflect the change in the ship’s status with regards to the weather.
Alaskan mariners, who have been discussed here more then once, will not understand this as they are in “it’s not if but when” mode all the time.[/QUOTE]
How many hundreds of hours have we all sat in the conference room at the training center staring at Power Point discussing “situational awareness”?
[QUOTE=highseasharry;178941]How many hundreds of hours have we all sat in the conference room at the training center staring at Power Point discussing “situational awareness”?[/QUOTE]
When we go through Gulf of Aden pirate country where the weather is all about the monsoon we focus on more on security and less on weather.
Ship’s crew’s today are under high workload. If we focus on one task inevitably we have to give something else less attention. It wouldn’t make sense to pay equal attention to pirates and weather regardless of where the ship is.
EDIT: This incident may have been simple lack of situational awareness. But situation awareness has to be within some kind of framework of what’s expected. What we pay attention to and what we expect is based on our experience. If this captain’s experience was all in areas of good weather, which is where most cruises are he may have had a high level of situation awareness but based on the wrong expectations.
Understanding how people typically interact with and make sense of their environment is an important element of situation awareness. The book “Managing he Unexpected” is a good one
I’ve always hated the way how people call cruise ships top-heavy and say things like "if it looks (doesn’t look) right, it is (isn’t) right.” I mean, I can understand how sailing boats say upright with their heavily ballasted keels, but the way how full-rigged “shipshape” ships sailed across storms decades is just some kind of dark magic.
Also, I don’t believe in sails in general. There must be something else propelling these vessels. Some kind of conspiracy.
[QUOTE=Tups;179015]I’ve always hated the way how people call cruise ships top-heavy and say things like "if it looks (doesn’t look) right, it is (isn’t) right.” I mean, I can understand how sailing boats say upright with their heavily ballasted keels, but the way how full-rigged “shipshape” ships sailed across storms decades is just some kind of dark magic.
Also, I don’t believe in sails in general. There must be something else propelling these vessels. Some kind of conspiracy.[/QUOTE]
Judging where the center of gravity is by eye is a “common sense” approach. The problem is that people writing about this, like our friend at Cruise Law, do not recognize that they are outside their area of expertise.
When handlilng a ship like this in bad weather one major factor, and one I haven’t seen given much attention, is the windage. I’ve seen lots of different wind speeds given, there is a screen shot showing 90 kts. If someone was to compute how many tons force that is on the side and how much power is available for turning I think we would see why the captain was having difficulties. Another important consideration is that a roll angle that most of us would consider acceptable is going to make many passengers believe that are about to die.
Given that the early forecasts suggested storm force conditions with the heaviest weather developing overnight Sunday into early Monday, perhaps the voyage plan might have taken the vessel clear of this area before the onset of the worse conditions.
RCL wants the public to believe that this vessel is built to withstand even more incredible forces? Come-on, I think this vessel was put to the limit and it’s a miracle that it didn’t break in half and sink taking 4,000+ lives with it - question authority! Someone said that the captain should be commended for his heroic seamanship - I think he was a fool! This seems to be a situation of corporate profit overriding passenger safety
[QUOTE=Kennebec Captain;179126]Here is a comment left at Cruse Law.[/QUOTE]
Just because Titanic broke in half in that freaking movie, it doesn’t mean that modern cruise ships with load-bearing superstructures have issues with longitudinal strength and snap in two that easily. I mean, I’m not a naval architect, but…
Of course I definitely agree that the master made the wrong decision when he sailed to the storm with passengers on board.
[I]When handlilng a ship like this in bad weather one major factor, and one I haven’t seen given much attention, is the windage. I’ve seen lots of different wind speeds given, there is a screen shot showing 90 kts. If someone was to compute how many tons force that is on the side and how much power is available for turning I think we would see why the captain was having difficulties. Another important consideration is that a roll angle that most of us would consider acceptable is going to make many passengers believe that are about to die.[/QUOTE][/I]
The wind indicators on large cruise ships are highly prone to read higher than the actual wind speed. This is due to the updrafts created when the wind is forced up and over the superstructure. It is true that the windage on this type of vessel is very significant, especially at slow speeds. They are lucky they didn’t lose propulsion, as well as not anywhere near a lee shore.
what is amazing to me is that not so long after the EL FARO’s horrible loss we have another vessel putting to sea into what was obviously a strong and potentially dangerous weather condition with plenty of warning of its severity. Once again we see commercial pressure being dumped onto a master’s shoulders to try to make the best of with who I am sure was NOT given an option to wait for it to pass. The powers of the MONEY are too STRONG and masters are too weak to stand up to it.
I AM BEGINNING TO CALL FOR EVERY SHIPMASTER TO DEMAND SAILING ORDERS IN WRITING WHEN AGAINST THEIR OWN OBJECTIONS! That is their legal right under the ISM Code and they must use it.
However, if this clown did not feel that the storm was a risk to sail into, then he needs to be cashiered forthwith and be frogmarched down the gangway! He risked a ship with thousands aboard needlessly!
There is no question the Anthem of the Seas should not have been where she was when she was. However it’s unlikely that it’s a simple matter of someone deciding to sail into 30 foot seas. More likely it was a case of insufficient safety margins in a changing situation.
In the video the captain said, based on the forecast, he expected 5 meter seas but he may not have taken into account possible changes in the track, timing or intensity of the system. Not to mention the lack of options stuck between the storm and the coast and the effects of the Gulf Stream.
Seems like the captain should have been geting some support on routing from ashore in this case.
Having grown up on the west coast of Norway and sailed in Alaska, he would be used to storms and should know how to handle the situation. But could this experienced Master have got “distracted” by the fact that he is command on one of the world’s biggest Cruise ships, with power and redundancy to handle “anything”??
The ship proved to stand up to it, with minor damages to furniture and fitting, but no structural damages.
Once he “hove to” and didn’t drive the ship hard into the seas the worst of the roll would have ceased. But obviously the pictures and media stories are about the heaviest rolls, probably when she was beam on and turning.
Sending the passengers and most of the crew to their cabins was a wise move. Having >6000 people milling around in the public areas, where things were flying around,could only lead to panic and more causalities.
In this case the ship was never in any danger of capsizing, nor did it suffer any serious damages, but if it had, how would they be able to evacuate that many people under those conditions??
[QUOTE=ombugge;179181]Having grown up on the west coast of Norway and sailed in Alaska, he would be used to storms and should know how to handle the situation.[/QUOTE]
It doesn’t matter where he’s from, complacency can happen to anyone. It has nothing to do with being used to or knowing how to handle storms. The issue is his weather routing ability which likely was compromised by years of operating in good weather areas.
The fact the tools like ECDIS change navigator’s perceptions has been discussed here and eleswhere. The tools used for ship routeing have chaged dramatically too.
When routeing around storms the ship usually skirts around the worse weather. But the relationship between level of risk, the nature of the wind/sea height field and the uncertainty in the forecast is sometimes not taken into account.
In cases where the wind/sea height gradient is not steep the route will have a built in safety margin as dangerous seas are far away. However in cases where the gradient is steep a small shift in the track, intensity or timing of the system may put the ship in unacceptable conditions.
I have seen the error of insufficient margin, that is too close to heavy weather, in routes provided by professional routeing services. The computer spits out a route that shows the ship within acceptable limits. It’s very difficult if not impossible for the ship’s crew to evaluate the level of risk in cases like this because informaton about uncertainty in the forecast is sometime not available or difficult to interpret.
[QUOTE=Kennebec Captain;179186]The fact the tools like ECDIS change navigator’s perceptions has been discussed here and eleswhere. The tools used for ship routeing have chaged dramatically too.
When routeing around storms the ship usually skirts around the worse weather. But the relationship between level of risk, the nature of the wind/sea height field and the uncertainty in the forecast is sometimes not taken into account.
In cases where the wind/sea height gradient is not steep the route will have a built in safety margin as dangerous seas are far away. However in cases where the gradient is steep a small shift in the track, intensity or timing of the system may put the ship in unacceptable conditions.
I have seen the error of insufficnt margin, that is too close to heavy weather, in routes provided by professional routeing services. The computer spits out a route that shows the ship within acceptable limits. It’s very difficult if not impossible for the ship’s crew to evaluate the level of risk in cases like this because informaton about uncertainty in the forecast is sometime not available or difficult to interpret.[/QUOTE]
All the wonderful tools that exist for route planning and weather routing from shore based sources obviously doesn’t absolve the Master from making his own decisions based on his experience and knowledge of that particular ship, it’s condition and seakeeping characteristics.
The decision should also change with the type cargo carried and other considerations that is not static.
When discussion routing for heavy lift vessels, especially if weather limitation is imposed, I frequently get met with the argument that “we got weather routing”.
I always tell them that weather forecast is just that. Forecast and weather routing is not always correct. You need to be prepared to divert from the planned route, alter course, reduce speed or “heave to” to reduce the motions to within the allowable limits.
