Cont: The Sinking of MS Estonia: Case Reopened Part V

[JayUtah]

However, the JAIC says on the day of departure it was seaworthy and there were no issues.

Asked and answered a hundred times. That phrase doesn't mean what you insist it means. It simply says that the ship was in a regulatory state of compliance.

However, it doesn't follow that because the bow visor had metal fatigue and corrosion, that ipso facto that must be the reason for the accident. There was zero time to even begin to evacuate the passengers, which tells you it was not a gradual scenario of one bit falling off after another, as with an old banger, but something cataclysmic and sudden.

No, that's not how to properly evaluate the root cause of an accident. For the love of Pete, please stop trying to be a forensic engineer. You have no talent for it whatsoever.

 

[The Man]

Welcome to my world. We all agree the vessel was in an unsatisfactory state.

However, the JAIC says on the day of departure it was seaworthy and there were no issues.

However, it doesn't follow that because the bow visor had metal fatigue and corrosion, that ipso facto that must be the reason for the accident. There was zero time to even begin to evacuate the passengers, which tells you it was not a gradual scenario of one bit falling off after another, as with an old banger, but something cataclysmic and sudden.

Of course it does follow both as cataclysmic and sudden and as one bit falling off. Particularly when the one bit that falls off is the whole bow of the ship.

 

[Vixen]

For example here is the Ventusky app for a location in the North Sea, chosen pretty much at random

https://www.ventusky.com/?p=53.75;4.68;6&l=wave

Showing the significant wave height, and showing the wind waves and swell waves directions.

You can clearly see that these two types of wave can be travelling in different directions at the same time

Of course, wave motion is complex, as is wind. Gusts are often circular. Waves lap, go forward, up against a wall, it hits it with spray in the air and a push back, etc., etc. There is no question that simply knowing windspeed and direction is a simplified rule of thumb, rather than an exhaustive analysis of wave behaviour.

Having said that and acknowledged that rarely are things as simple as a 'rule of thumb' it doesn't mean wind parameters are not a useful measure when out at sea.

 

[JayUtah]

Having said that and acknowledged that rarely are things as simple as a 'rule of thumb' it doesn't mean wind parameters are not a useful measure when out at sea.

"Wind parameters" do not by themselves dictate the behavior of sea waves. You're trying to argue that they do. Specifically you're claiming that one "wind parameter" -- the wind speed -- allows window designers to spec out windows to withstand the impact of waves occurring when the wind is blowing that hard.

That's simply made up. No such connection exists. No such design parameter or method exists.

 

[Mojo]

In the UK the Prime Minister is delegated the power to command the armed forces by the Queen. Chief of the Defence Staff (CDS) is the professional head of the British Armed Forces and is appointed by the Prime Minister. Currently he is Admiral Sir Tony Radakin.

He can be replaced or removed by the PM.

Sure, in theory, the monarchy can be got rid of by an Act of Parliament but it is hardly going to happen, with the 'men in grey' éminence grise in place.

Did you actually read the post you were replying to there?

 

[GlennB]

Did you actually read the post you were replying to there?

That would be an unexpected novelty.

 

[JesseCuster]

And WHAT force drove the waves to smash the windows in the first place?

The wind.

The point is that you repeatedly claimed that wind couldn't have broken the windows and that the windows were designed to withstand 41 metres per second wind speed, despite the fact that you were repeatedly told that it wasn't wind that broke the windows.

Now that you can no longer ignore being corrected about what caused the windows to break, you're stubbornly sticking to the idea that it's all about wind, hence your waffling about wind speeds and pointless waffle about how wind can knock down trees and power lines and other irrelevant guff, because you cant just admit your were wrong about what caused the windows to break so you must cling to the idea that it's all about wind.

 

[Andy_Ross]

For waves to smash the Deck 4 and 5 windows, the JAIC had to claim the waves would have jumped up at a weird angle (bearing in mind the list is 50° to 70° for twenty minutes before sinking when it should have capsized within seconds at that angle [assuming no breach in the hull]) and in disconnecting the bow visor, they somehow had the power to change direction to back and up, having just bashed the nose forward and aft. From knowing the windspeed that night we are able to estimate wave height as being between 4m - 6m.



From the windspeed, we can ascertain what the wave height is and from that, depending in the wind direction and speed of the vessel, the level of impact.

wiki


Just that one little measure tells you a whole story. What we are missing is information as to the level of resistance of the glass used as windows or the inner dividers on those decks. It is my understanding that these passenger ferries used glass designed to withstand a wind speed factor of 41 m/s, which obviously takes into account the likely power of a wave emanating from such a wind speed.

The waves smashed the windows as the ship had lost power and was listing to starboard bringing the windows within reach of the waves.
It turned broadside on to the waves when it lost power. Any ship that loses forward motion will turn broadside on to the wind or waves.

 

[Reformed Offlian]

The wind.

The point is that you repeatedly claimed that wind couldn't have broken the windows and that the windows were designed to withstand 41 metres per second wind speed, despite the fact that you were repeatedly told that it wasn't wind that broke the windows.

Now that you can no longer ignore being corrected about what caused the windows to break, you're stubbornly sticking to the idea that it's all about wind, hence your waffling about wind speeds and pointless waffle about how wind can knock down trees and power lines and other irrelevant guff, because you cant just admit your were wrong about what caused the windows to break so you must cling to the idea that it's all about wind.

I hope we aren't going to slide into discussing the obvious non sequitur that, if a window can withstand a certain-strength wind, it can therefore withstand impact from anything blown/carried by that wind.

 

[Andy_Ross]

So tell me, what came first, the list at >40° or the bow visor disconnecting?


It lost power because the four engines cut out. And that would have been because of the list.

So, which came first, the violent list, or the bow visor dropping?

It lost the bow visor and took on water, the water caused the list.
Engines cut when the list got past an angle where the oil in the engine sump could no longer be pumped.
When power was lost the ship turned broadside on to the waves.
With the woindows close to the surface of the water the waves were able to impact and smash them.

 

[Vixen]

"Wind parameters" do not by themselves dictate the behavior of sea waves. You're trying to argue that they do. Specifically you're claiming that one "wind parameter" -- the wind speed -- allows window designers to spec out windows to withstand the impact of waves occurring when the wind is blowing that hard.

That's simply made up. No such connection exists. No such design parameter or method exists.

I was claiming nothing of the sort. Shipbuilding specs are extremely complex and I wouldn't presume to claim otherwise.

Actually, jimbob's link was very interesting, because of course, one of the reasons the North Sea can be so tempestuous is because there is also the factor of currents. So you have currents coming up from the Atlantic, meeting currents from the North Sea. Combined with areas of different barometric pressures on top, the North Sea is not going to look like a calm gentle ride in the North Sea any time soon.

 

[Andy_Ross]

Welcome to my world. We all agree the vessel was in an unsatisfactory state.

However, the JAIC says on the day of departure it was seaworthy and there were no issues.

It does not say that at all. IF you read the report it says that according to it's certification it was fit to sail It then goes on to detail why the certification was inadequate and why the ship itself was not in compliance.

 

[Reformed Offlian]

It does not say that at all. IF you read the report it says that according to it's certification it was fit to sail It then goes on to detail why the certification was inadequate and why the ship itself was not in compliance.

It's a bit like saying my car has a current safety inspection sticker. Noting that is not equivalent to claiming that there is nothing wrong with my car.

 

[Vixen]

The wind.

The point is that you repeatedly claimed that wind couldn't have broken the windows and that the windows were designed to withstand 41 metres per second wind speed, despite the fact that you were repeatedly told that it wasn't wind that broke the windows.

Now that you can no longer ignore being corrected about what caused the windows to break, you're stubbornly sticking to the idea that it's all about wind, hence your waffling about wind speeds and pointless waffle about how wind can knock down trees and power lines and other irrelevant guff, because you cant just admit your were wrong about what caused the windows to break so you must cling to the idea that it's all about wind.

If wind speed conditions of 25 m/s had the effect of waves smashing the passenger ferry windows, it would be happening all the time. As the Captain of Silja Europa and On-Scene-Commander says:

Esa Mäkelä, the captain of Silja Europa who was appointed on-scene commander for the subsequent rescue effort, described the weather as "normally bad", or like a typical autumn storm in the Baltic Sea.

wiki


If the vessel was on its side, it doesn't prove that the reason for sinking was a smashing of windows, in order to fulfil the requirement of 4,500 tonnes of water.

Another similar vessel had a fault with the bow visor and it managed to sail for two and a half hours into port without capsizing despite the thing being open.

 

[Vixen]

The waves smashed the windows as the ship had lost power and was listing to starboard bringing the windows within reach of the waves.
It turned broadside on to the waves when it lost power. Any ship that loses forward motion will turn broadside on to the wind or waves.

IIRC the JAIC determined that the ship had been steered by a navigating officer to the west in order to try to correct the trim.

It wasn't just by accident, it was by design, apparently.

 

[Vixen]

It lost the bow visor and took on water, the water caused the list.
Engines cut when the list got past an angle where the oil in the engine sump could no longer be pumped.
When power was lost the ship turned broadside on to the waves.
With the woindows close to the surface of the water the waves were able to impact and smash them.

So, it lost the bow visor at 0115. But the initial list 40° - 50° happened at least fifteen minutes earlier.

 

[jimbob]

I was claiming nothing of the sort. Shipbuilding specs are extremely complex and I wouldn't presume to claim otherwise.

Actually, jimbob's link was very interesting, because of course, one of the reasons the North Sea can be so tempestuous is because there is also the factor of currents. So you have currents coming up from the Atlantic, meeting currents from the North Sea. Combined with areas of different barometric pressures on top, the North Sea is not going to look like a calm gentle ride in the North Sea any time soon.

It's rarely currents. It's mostly waves caused by the wind a long distance away.

And these waves are not caused by the local wind direction either

[imgw=450]https://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Ile_de_r%C3%A9.JPG/512px-Ile_de_r%C3%A9.JPG[/imgw]
Ile de ré
Michel Griffon, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

 

[MarkCorrigan]

Not a like-for-like situation.


You need to know how deep/shallow that water is and what it is acting on that wave to make it move. So, you could have a wind speed of 25 mph and also a wave at 25mph if you have some guy driving a speedboat through the water to cause a wave of that exact velocity. But what would be the point of such an exercise?

Hey, you answered my question! That might be a first.

So do you consider yourself well versed enough in fluid dynamics to be able to accurately determine the upper limits for the windows?

Do you consider yourself well versed enough on naval architecture to properly assess the JAIC report?

 

[Andy_Ross]

I was claiming nothing of the sort. Shipbuilding specs are extremely complex and I wouldn't presume to claim otherwise.

Actually, jimbob's link was very interesting, because of course, one of the reasons the North Sea can be so tempestuous is because there is also the factor of currents. So you have currents coming up from the Atlantic, meeting currents from the North Sea. Combined with areas of different barometric pressures on top, the North Sea is not going to look like a calm gentle ride in the North Sea any time soon.

At the moment forecast for Cromarty, Forth, Tyne, Dogger, Fisher, German Bight and Humber is Moderate or Rough.


Sea State in Dogger which is off my coast is a Sea of 2.6m, a Chop of 1.7m giving a Swell of 1.9m.
Wind at the moment is North Westerly 24kt with gusts of 31kt.

Wind backing to South Westerly overnight then back to NW.

Not Spinnaker weather but not too bad with a well reefed main.

 

[Steve]

I hope we aren't going to slide into discussing the obvious non sequitur that, if a window can withstand a certain-strength wind, it can therefore withstand impact from anything blown/carried by that wind.

Too late. We are already there. There are many, many paths in this garden. Some have still not been travelled. But Vixen will open the gates leading to them and they will be, oh they will be.