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-   -   Suez canal blocked (https://www.pprune.org/jet-blast/639461-suez-canal-blocked.html)

DaveReidUK 26th Mar 2021 22:05


Originally Posted by Jonno_aus (Post 11016919)
Me either. Every news article I’ve read all report the same thing from authorities, and that there was a large sandstorm and it was hit by 50 km/h wind gusts that pushed it into the bank.

The BBC, who initially reported the power/steering failure, now saying that "initial investigations have ruled out any mechanical or engine failure as a cause of the grounding".

Low Level Pilot 26th Mar 2021 22:29

Posts 58 and 155 point to a strong possibility.
If the ship is off the centre line, but parallel to the bank, the water is flowing faster down the narrow side, causing a pressure difference between the two sides.
If the helmsman doesn't pick up on the problem straightaway then the pressure difference will suck the ship sideways.
The later you try to correct the problem, the bigger the problem becomes.
When you put on helm to turn the ship back to the centreline the stern moves closer to the bank.
You are now creating a wedge. The water is moving even faster down the narrow side, and you have made the gap between the stern and the bank less than at the
bow, so the water is now moving even faster at the stern than the bow, causing more suction which drags the stern towards the bank. Helm needs to be reduced to stop
an uncontrollable swing, possibly even opposite helm in order to create an ever worsening situation.
If the stern gets to close to the bank then the amount of water flowing down that side cannot escape and can even stop flowing. At this point the ship will shear off rapidly
towards the opposite bank. There is only one answer that I know of when this happens, full opposite helm and full ahead with fingers crossed you have caught the shear in time.
However in this instance, if this is what happened, the remedy probably wouldn't work because the engine on a ship this size would be too slow to react. So the inevitable occurs
and the bow is buried in the bank.
If you manage to catch the shear and the ship starts to swing in the opposite direction then its stop engine, full helm the opposite way, full ahead and get the second shear under control.
Percieved wisdom is that you have 3 attempts. If you not are back under control after go three then you have failed and the only remedy left is full astern and drop both anchors.
Again on a ship of this size going from ahead to astern will take longer than the time it takes to connect with the bank.
That is mostly for effect because it looks better on the report afterwards that the final engine movement was full astern.
Why not go full astern anyway you are probably asking? Going full astern results in transverse thrust kicking in. A ship with a fixed right handed propellor will veer off to
starboard, how quickly depends on the design of the ship. In any case by the time the engine is running astern it will be too late, which is why you try and rectify the situation as above.

This of course assumes there wasn't an engine failure! There are reports that the negine didn't fail.

The bank effect increases with draught and beam in relation to the width and depth of the waterway, the values of which determine the 'blockage factor'. On overbeam ship
will have a draught limitation less than the max for the waterway.
Due to ever increasing pressure of economics some of these ships are designed with a dead slow speed which is ridiculously high, I have heard of some as high as 8 knots.
Doesn't sound very much, but together with the displacement of these box boats thats a lot of inertia. I don't have any idea what the DS speed of the Evergiven is, but as already mentioned speed is
a major factor in bank effect.
Whilst a Suez Canal transit requires a pilot to be on board he wouldn't be steering. That is done by one of the ship's crew, the pilot oversees him and gives him the helm orders.




TURIN 26th Mar 2021 23:32

Low-level Pilot.
Very informative. Thankyou.

sycamore 26th Mar 2021 23:38

LLP,thank you for such a comprehensive explanation...however,looking at the pics ,it appears as if you can`t see the pointy bit at the front,not even a mast,so is it all controlled by the compass,GPS( Localised ground based) and radar,or men on the external wing bridges....?
It was mentioned that it has `bow thrusters`...are these used continuously during the transit...?I assume these are elecrtric and faster responding than main engine...?

chinaman1119 27th Mar 2021 01:00

This being Jet Blast and all, this just begs to be posted :)

On a side note to the big issue of the blockage ...
Anyone noted the reports that the Ever Given engaged in some crafty "art work" during their waiting time prior to entering the canal?

I appears that they drew a uhhhmm ... an ehhhh ... well, a male genital device including crown jewels and (this is open for interpretation) a pair of a$$ cheeks. Google is willing to present pics and links.

Loose rivets 27th Mar 2021 01:33

I don't think she can turn in little circles, especially for entertainment, and extra-especially as the boss would have the picture on his desk before the artwork was signed.

jolihokistix 27th Mar 2021 02:36

With reports of water ingress and possible structural 'sagging', what are the best and the worst case scenarios, or should we not ask the latter?

NutLoose 27th Mar 2021 03:59

Dig a lay-by and park it ;)

clark y 27th Mar 2021 04:18

The ship seems really dug in when you consider the difference from bow to stern in the images.

L'aviateur 27th Mar 2021 04:34


Originally Posted by lomapaseo (Post 11017035)
Does anybody have a hint about the results of estimating wind velocity vs ship area( including visible load) vs ship mass to resolve expected side slip vs time against normal power and manueverability,. In other words what reaction time does the crew have in avoiding beaching in a narrow canal?

That way we can tell if it was response critical but doable or they were doomed by a loss of maneuverability

Windage, lee way and swept path can all be calculated. This kind of information isn't usually considered on a case by case basis, but should have been studied in depth during simulations by the Canal Authority when approving a class/size of ships for transit. As for whether the Suez Pilot is properly trained and equipped for threat and error management? I suspect not to the level that we are in countries like Australia.

L'aviateur 27th Mar 2021 04:35


Originally Posted by clark y (Post 11017126)
The ship seems really dug in when you consider the difference from bow to stern in the images.

That could be deceptive due to how the ship is 'trimmed'.

L'aviateur 27th Mar 2021 04:39


Originally Posted by jolihokistix (Post 11017111)
With reports of water ingress and possible structural 'sagging', what are the best and the worst case scenarios, or should we not ask the latter?

Worst case is it having to be cut up in situ and taken away in sections, although I suspect that the salvage company will be doing there utmost to avoid that. The best case is for it to be refloated and able to proceed with assistance to the nearest suitable container terminal (Port Said?) to discharge cargo and then proceed to drydock for repairs.

L'aviateur 27th Mar 2021 04:48


Originally Posted by sycamore (Post 11017075)
LLP,thank you for such a comprehensive explanation...however,looking at the pics ,it appears as if you can`t see the pointy bit at the front,not even a mast,so is it all controlled by the compass,GPS( Localised ground based) and radar,or men on the external wing bridges....?
It was mentioned that it has `bow thrusters`...are these used continuously during the transit...?I assume these are elecrtric and faster responding than main engine...?

Bow Thrusters installed, but largely ineffective once the forward speed exceeds 3 knots (average transit speed is 6-8 knots). Primary Navigation is visual (even without full visibility of the bow) using gyro compass, radar and GNSS navigation aids. (A little bit here about how they train https://www.wartsila.com/insights/ar...the-suez-canal )

clark y 27th Mar 2021 05:05

L'aviateur, fair point.

jolihokistix 27th Mar 2021 05:35

L’aviateur, many thanks re post#212 above.

sycamore 27th Mar 2021 11:11

Laviateur, Merci M. ...

SpringHeeledJack 27th Mar 2021 12:19


Worst case is it having to be cut up in situ and taken away in sections, although I suspect that the salvage company will be doing there utmost to avoid that. The best case is for it to be refloated and able to proceed with assistance to the nearest suitable container terminal (Port Said?) to discharge cargo and then proceed to drydock for repairs.
Due to the size of this monster probably only Dubai, France or Greece would be able to accommodate it in dry dock. Either that or schlep back to Korea.

Low Level Pilot 27th Mar 2021 13:29

You don't actually need to see the pointy bit, although it helps. You tend to look into the mid distance and use the foremast. More important is knowing ere the stern is. In a narrow waterway the pivot point tends to move aft and you want to keep the body of the ship some 3/4 of the length from the bow on the centreline. That's why on a bend we put the bow into the outside of the bend before turning. we then use the bank effect to push the bow round and control the rate of turn accordingly. Quite normal to go round a bend with opposite helm on. if you turn to soon and end close to the inside of the bend you will end up 'stuck' to it.
Conventional ships with the bridge aft are much easier to keep in position as you can see were the pivot point is.
I don't know why she took a shear, there are many factors to be ascertained. Wind , visibility, helmsmans experience, was there an unknown sandbank caused by wind blowing sand into the canal?

Stockportcounty 27th Mar 2021 14:00

Could this be a new Watergate ?

Cpt_Pugwash 27th Mar 2021 14:57

In other news ..
https://cimg6.ibsrv.net/gimg/pprune....af1f59d293.jpg

BREAKING NEWS : Yorkshire holds it breath as main shipping route of pork pies is blocked !!
Fred Slathwaite , Captain of the vessel, said “ One minute we were fine , then a gust of wind caught us !!”
“Yorkshire is expected to loose as much as £3.45 a day until the carnage can be cleared , which could potentially take weeks to clear “ a spokesman said .


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