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

[Andy_Ross]

3.2.6. JAIC Report

The 'scuppers' in this case are not holes, they are drain pipes, they are tiny, the same size as a drain pipe for your guttering, they are not direct holes in the side of the ship.

The ship travelling almost westwards was almost head-on with the southwesterly waves. These waves were rising up and hitting the bow and its forepeak deck head on as the ships sped along at 15 knots.

Think about it. The bow falls off. The ship lists severely enough to cut out the engines. The water on the car deck is to the aft and to the starboard.

Consequently when it turns or drifts into the opposite direction, it is the stern which is now being lifted up by the waves. The bow is on the down wave and no more water is pouring into the car deck (as the car deck and accommodation decks are over two metres above sea level and are not part of the hull) as the waves are no long in that direction. On the downward motion, all the water on the car deck now simply pours off, just as it does on the promenade and weather decks and there are no waves smashing in. All the wave action is now at the stern end.

You haven't a clue, the ship is still pitching in to the waves, the bows are still burying themselves in the sea, the ship is still moving forwards. After power was lost the ship was broadside, listing and low in the water as it sank.

 

[erwinl]

Even the JAIC concur the gap in the car ramp was about one metre at most, thus only the very highest of waves were ingressing.

IMV there is zero evidence the car deck was ever significantly flooded.

The JAIC had to admit that even if the entire car deck up to the roof was flooded, there still need to be significantly more ingress of water for it to capsize and sink.

Vessels of that size were generally designed to be able to withstand the flooding of two watertight bulkhead compartments. The Estonia had 15 watertight bulkhead compartments in the hull (Deck 0). The only accessible areas were the Engine Control Room, the swimming pool, public toilets and the sauna, all of which had tight waterproofed doors with gaskets for persons coming in or out.

4"scuppers.
How wide were these scuppers?
If they were only 4"wide (this being square or circular), there is no way, they could provide the needed area to counter even a one meter gap in the bow. Let alone greater.

 

[Andy_Ross]

3.2.6 Car deck arrangement

Twelve closable 4" scuppers were installed along each side of the deck. The scuppers were normally left open.

JAIC Report

There are also 'sides' to the cafeteria, shop, pub, accommodation.

The 'scupper' in this case are drains in the deck the size of a drainpipe for your house gutters. They are tiny, they are not designed to remove tons of water.

As you know the size of the drains you can work out the flow rate for them.

 

[zooterkin]

The car deck is flat, is it not?

It is not cup-shaped.

If you have ever tried washing a baking tray with 1mm sides by hand then you would know that water washes straight off it.

3.2.6 Car deck arrangement

Twelve closable 4" scuppers were installed along each side of the deck. The scuppers were normally left open.

JAIC Report

There are also 'sides' to the cafeteria, shop, pub, accommodation.

You're comparing 12 closable scuppers on each side (4ft total length, length of ferry, >500 ft, so less than 1%) to a baking tray with 1mm sides and saying they would drain the same way?

 

[Steve]

Even the JAIC concur the gap in the car ramp was about one metre at most, thus only the very highest of waves were ingressing.

IMV there is zero evidence the car deck was ever significantly flooded.
The JAIC had to admit that even if the entire car deck up to the roof was flooded, there still need to be significantly more ingress of water for it to capsize and sink.

Vessels of that size were generally designed to be able to withstand the flooding of two watertight bulkhead compartments. The Estonia had 15 watertight bulkhead compartments in the hull (Deck 0). The only accessible areas were the Engine Control Room, the swimming pool, public toilets and the sauna, all of which had tight waterproofed doors with gaskets for persons coming in or out.

The car deck is currently completely flooded, and has been for many years.

 

[Vixen]

What is, in your opinion, the effect on stability, if the centre of Gravity is not a fixed point, but moving all over the place?

In my humble opinion, once the point of stability was negative (unstable as of circa 40° - 45°) without drastic righting action by the crew, it should have capsized and turned over almost immediately, pulled over by gravity, and then as the righting arm in the opposite direction now came into play, once toppled (think of a capsized rowing boat).

Enter new hypothesis. 'Ah. Excess water must have come in via the windows of Decks 4 and 5 whilst it was leaning to starboard which is why it took so long to sink, whilst it filled up.'

Yet a VINNOVA state sponsored study showed the ship would need to be flooded by 83% of it superstructure and with at least double the amount of ingressed water than the 4,500 tonnes the JAIC calculated.

There were 720 cabins. If each of those inner dividers needed to be breached, there should surely have been time to evacuate the passengers in the interim.

 

[erwinl]

In my humble opinion, once the point of stability was negative (unstable as of circa 40° - 45°) without drastic righting action by the crew, it should have capsized and turned over almost immediately, pulled over by gravity, and then as the righting arm in the opposite direction now came into play, once toppled (think of a capsized rowing boat).

Enter new hypothesis. 'Ah. Excess water must have come in via the windows of Decks 4 and 5 whilst it was leaning to starboard which is why it took so long to sink, whilst it filled up.'

Yet a VINNOVA state sponsored study showed the ship would need to be flooded by 83% of it superstructure and with at least double the amount of ingressed water than the 4,500 tonnes the JAIC calculated.

There were 720 cabins. If each of those inner dividers needed to be breached, there should surely have been time to evacuate the passengers in the interim.

Aside from the fact that a point can't be negative, you're only looking at the shifting in starboard and port directions.
What if the centre of gravity not only moves from left to right, but also fore, and more importantly, aft?

 

[Vixen]

Now, this, I'd like to see a source from you.
That this is exactly what they said and not how you interpreted it.

12.6.1 Floating conditions and stability during flooding

Even though the list developed rapidly; the water on the car deck would not alone be sufficient to make the ship capsize and lose its survivability As long as the hull was intact and watertight below and above the car deck, the residual stability with water on the car deck would not have been significantly changed at large heel angles. The capsize could only have been completed through water entering other areas of the vessel.

ibid

JAIC Report.

 

[erwinl]

12.6.1 Floating conditions and stability during flooding


ibid

JAIC Report.

Thanks.
Based on this text I found it.
It does say something about what would happen with only 2000 tons of water on the cardeck, though.

 

[Vixen]

Aside from the fact that a point can't be negative, you're only looking at the shifting in starborad and port directions.
What is the centre of gravity not only moves from left to right, but also fore, and more importantly, aft?

In the case of a ship in water, you would be looking at the metacentric height, the centre of bouyancy and the centre of gravity to calculate the Gz value. This changes depending on how low in the water a vessel is, the angle of list and the deadweight, together with other salient factors. A boat is designed to rock from side to side to flow with wave action, so a list to one side is self-corrected by a self-righting imaginary 'arm', based on the aforesaid parameters.

So if a boat lists to the excess of the Gz formula it is now unstable, It will momentarily stabilise as it reaches the critical point, before toppling over and now the righting arm comes back into play again. Some vessels are designed to bob straight back up again once capsized. Broadly speaking, boats and ships and designed to not sink just as aeroplanes are designed not to drop from the sky.

The simple answer as to why the Estonia sank and sank rapidly, is because it suffered a breach in its starboard side, together with a likely explosive device that weakened the locks, nuts and bolts of the car ramp and bow visor sufficiently enough to detach them.

The big questions are, why, how and by whom or what.

These, the JAIC steered well clear of!

 

[erwinl]

In the case of a ship in water, you would be looking at the metacentric height, the centre of bouyancy and the centre of gravity to calculate the Gz value. This changes depending on how low in the water a vessel is, the angle of list and the deadweight, together with other salient factors. A boat is designed to rock from side to side to flow with wave action, so a list to one side is self-corrected by a self-righting imaginary 'arm', based on the aforesaid parameters.

So if a boat lists to the excess of the Gz formula it is now unstable, It will momentarily stabilise as it reaches the critical point, before toppling over and now the righting arm comes back into play again. Some vessels are designed to bob straight back up again once capsized. Broadly speaking, boats and ships and designed to not sink just as aeroplanes are designed not to drop from the sky.

The simple answer as to why the Estonia sank and sank rapidly, is because it suffered a breach in its starboard side, together with a likely explosive device that weakened the locks, nuts and bolts of the car ramp and bow visor sufficiently enough to detach them.

The big questions are, why, how and by whom or what.

These, the JAIC steered well clear of!

No. I'm looking at the centre of gravity.
Under ordinary circumstances this would be a fixed point somewhere in the ship (we're ignoring changes in fuel usage or balast in this one). (and yes, I'm sure Captain Swoop is about to sweep upon me, for saying nonsense)
.
During normal operations the centre of bouyancy does indeed change and both of these tend to work together to right the ship again (under normal circumstances).

But what if that centre (or is it center?) of gravity changes its position?
What would be the effect of that?

 

[Mojo]

The simple answer as to why the Estonia sank and sank rapidly, is because it suffered a breach in its starboard side, together with a likely explosive device that weakened the locks, nuts and bolts of the car ramp and bow visor sufficiently enough to detach them.

The big questions are, why, how and by whom or what.

These, the JAIC steered well clear of!

Reset ahoy!

 

[Vixen]

No. I'm looking at the centre of gravity.
Under ordinary circumstances this would be a fixed point somewhere in the ship (we're ignoring changes in fuel usage or balast in this one). (and yes, I'm sure Captain Swoop is about to sweep upon me, for saying nonsense)
.
During normal operations the centre of bouyancy does indeed change and both of these tend to work together to right the ship again (under normal circumstances).

But what if that centre (or is it center?) of gravity changes its position?
What would be the effect of that?

Traditionally it is transverse midships but is also longships, depending on why you need to know what it is.

What would be the point in picking random points? Maybe it becomes relevant when loading cargo.

I can't see what point you are trying to make. The centre of gravity being by definition the midpoint of a whole range of points.

 

[Andy_Ross]

Even in a storm?

They aren't holes in the side, they are drains in the deck that lead overboard.

 

[Andy_Ross]

In my humble opinion, once the point of stability was negative (unstable as of circa 40° - 45°) without drastic righting action by the crew, it should have capsized and turned over almost immediately, pulled over by gravity, and then as the righting arm in the opposite direction now came into play, once toppled (think of a capsized rowing boat).

Enter new hypothesis. 'Ah. Excess water must have come in via the windows of Decks 4 and 5 whilst it was leaning to starboard which is why it took so long to sink, whilst it filled up.'

Yet a VINNOVA state sponsored study showed the ship would need to be flooded by 83% of it superstructure and with at least double the amount of ingressed water than the 4,500 tonnes the JAIC calculated.

There were 720 cabins. If each of those inner dividers needed to be breached, there should surely have been time to evacuate the passengers in the interim.

A ship's superstructure is not watertight, cabin dividers and doors are not watertight. Breaking windows will have increased the rate of flooding but they aren't needed. What sank the Estonia was the hull flooding.

 

[Andy_Ross]

In the case of a ship in water, you would be looking at the metacentric height, the centre of bouyancy and the centre of gravity to calculate the Gz value. This changes depending on how low in the water a vessel is, the angle of list and the deadweight, together with other salient factors. A boat is designed to rock from side to side to flow with wave action, so a list to one side is self-corrected by a self-righting imaginary 'arm', based on the aforesaid parameters.

So if a boat lists to the excess of the Gz formula it is now unstable, It will momentarily stabilise as it reaches the critical point, before toppling over and now the righting arm comes back into play again. Some vessels are designed to bob straight back up again once capsized. Broadly speaking, boats and ships and designed to not sink just as aeroplanes are designed not to drop from the sky.

The simple answer as to why the Estonia sank and sank rapidly, is because it suffered a breach in its starboard side, together with a likely explosive device that weakened the locks, nuts and bolts of the car ramp and bow visor sufficiently enough to detach them.

The big questions are, why, how and by whom or what.

These, the JAIC steered well clear of!

Apart from the chapters that dealt with the stability of the ship you mean?

 

[Andy_Ross]

Traditionally it is transverse midships but is also longships, depending on why you need to know what it is.

What would be the point in picking random points? Maybe it becomes relevant when loading cargo.

I can't see what point you are trying to make. The centre of gravity being by definition the midpoint of a whole range of points.

How do you know? Your only knowledge of this is the random snippets you have found on google.

 

[Vixen]

News Update

Henrik Evertsson and Linus Andersson are to face trial again under the terms of allegedly breaking the Estonia Grave Site Treaty. They had been acquitted last year because it was adjudged the wreck is in international waters, so there was no jurisdiction. An Appeal Court has upheld the Swedish state prosecutor's appeal and it looks like the two men will now be tried again. I believe Evertsson lives in Norway and Andersson in Finland (AIUI from newspaper interviews), so it might not happen until they set foot on Swedish soil.

The two men were originally acquitted of violating Swedish law, as they had used a foreign German-flagged vessel to film the site.

But an appeal's court ruled on Tuesday that the Estonia Act should apply in their case and ordered for the documentary makers to face trial again.

"Since the district court has not tried all the objections raised by the defendants, the Court of Appeal has decided that the case should be tried again by the district court," the Gothenburg court said in a statement.

The two men were arrested while filming in September 2019 by the Finnish coast guard and face a fine or up to two years in prison if convicted.

ERR

 

[erwinl]

Traditionally it is transverse midships but is also longships, depending on why you need to know what it is.

What would be the point in picking random points? Maybe it becomes relevant when loading cargo.

That's one reason

I can't see what point you are trying to make. The centre of gravity being by definition the midpoint of a whole range of points.

It also ties in with this post of yours.

If the vessel was relentlessly pitching and ploughing against huge waves that permeated the [sealed] car deck (the waves lapping in, and lapping out on the downward motion), then as soon as it turned in the opposite direction to the oncoming waves, this time it is the stern lurching downwards and upwards, depositing said water from the [presumed] open bow as it does so, spilling it back out into the sea. The car deck is part of the superstructure, not the hull. It has scuppers at the side to additionally drain off excess water, as do the promenade decks.

What would be the effect on the Estonia if the centre of gravity changes its position uncontrolled?
Like for instance going aft?

 

[erwinl]

They aren't holes in the side, they are drains in the deck that lead overboard.

Thanks.

I had indeed holes (with some kind of closing flap) in the side of the hull in mind and could not understand why these would be open in a storm.

If they're drains I can imagine it better and see why that on itself would not be such a problem.