Suez Canal blocked by container ship 36

[verymadmac]

It might not be an engineering issue that started it, but I bet is going to change a few specifications.
BBC piece here Link



It looks like the bow is hard aground, refloating will be an interesting exercise given the time pressure.



Canal profile is here

https://www.suezcanal.gov.eg/English/About/SuezCanal/Pages/CanalCharacteristics.aspx

 

[Tomfh]

This places a huge bending load on the hull.

What are the design loads for ships like this?

Do you design for the ship being supported by its bow?

 

[TugboatEng]

Absolutely not. Each ship has strict limits on shear and bending. To much weight in the middle or on the ends causes hogging or sagging. Balanced but concentrated weight causes shear.

Here you see an example of a ship that hogged to death.

Also, any buckling of the bottom plating caused either directly by contact during ground or excess stresses severely weaken the hull. The ship will have to be unloaded to reduce stresses before transportation on oceans.

 

[FacEngrPE]

You design a ship to be supported by water.

The design case is hogging or sagging.

https://en.wikipedia.org/wiki/Hogging_and_sagging

The design case is waves positioned for highest stress in both cases. Tugboat's example the wave height likely was significantly higher then the design case for long enough for fatigue to take control of the hull. Then you have a hull in pieces.

Grounding can easily create stresses not accounted in the design case. There is some risk of wrinkling the hull. Less risk of cracking the ship in half from a single event unless their are already undetected cracks.

 

[TugboatEng]

Note that groundings in the canal are common. A similar ship grounded just 4 months ago and it was hardly an event.

https://www.fleetmon.com/maritime-n...ontainer-ship-grounding-during-suez-canal-tr/

It's not normal for ships to end up perpendicular. I'd be curious to see what the rudder position is at this moment.

 

[FacEngrPE]

Introduction To Steel Shipbuilding by Baker, Elijah 1943 Page 229 explains that at the time the highest loads a ship incurred where when launching, first floating a ship, from an inclined shipway. No one does that with these very large ships, the launching loads would be too high.
Figure 91 , page 102 of this reference illustrates the wrinkling described by tugboat. Physics today is the same as 1943. We do not get to wave the rules due to inconvenience.
,

 

[dik]

Are the ships long enough and massive enough that Coriolis accelleration becomes an issue in their design?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[EdStainless]

I presume that they are also pumping out the forward tanks to lighten the bow.
Steering gear failures are not unheard of.
The BBC report said that 2 pilots were on board. My guess is that one was just in transit.
Yes, it will limp out of the canal and then be off loaded, there is repair and survey work to be done before it carries cargo again. Insurance companies are so picky.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[FacEngrPE]

One of the reports indicated that high capacity pumps are needed to pump out the forward void space. That implies there is a hole somewhere in the bulb bow embedded in the sand.

 

[CWB1]

Possibly had a 12-year old boy at the helm

https://www.huffpost.com/entry/suez-canal-blocked-...

This New York Post title states it clearly. . . . . . .

https://nypost.com/2021/03/24/cargo-ship-drew-peni...

As that perpetually immature, juvenile'ish guy that loves an overdone sex joke.....I find it amazing that multiple pages published such a dumb thought. I'm pretty sure I've seen more phallic drawings out of the preschoolers.

 

[dik]

Maybe one was the Egyptian, that I understand is required...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

What is the purpose of the 'bulb bow'?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[TugboatEng]

It creates destructive interference to counteract the transverse wake generated by the ship which saves fuel.

Here in San Francisco.Bay we require two pilots on ships this large. One is in the pilothouse and the other is on the bow of the ship.

 

[dik]

thanks...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

I knew I shouldn't have asked... I just had to look the answer up... thank again, tugboat...

https://wikiwaves.org/Ship_Kelvin_Wake

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[hokie66]

The Suez pilots like cruise ships, which are scarce at the moment. They come on for a free feed, so sometimes there are more than the required two. I think the main requirement for those pilots is agility for embarking and disembarking, so perhaps their seamanship is secondary.

 

[dik]

If they are responsible for piloting, then Egypt may be on the hook for some real damages.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[TugboatEng]

If the pilot is determined to be at fault. I still think this is a mechanical fault. The angle of incidence is too perpendicular unless there was a second ship involved.

Check out how an improperly executed overtaking maneuver can doom the ship being passed. Though at 13 knots it's unlikely.the Given was being overtaken.

https://youtu.be/dq8EQVl7GG0

Also see the correct method, it's quite complicated.

https://youtu.be/3NqN_yNrR8Y

Port Revel is in France and they train pilots from everywhere in the world. Their channel is fascinating and a good way to kill a weekend.

https://youtube.com/c/PortRevel

Also, one of my coworkers.who excelled at ship handling early and is now a pilot suggested this video explaining pivot point and how ships turn. This is important to understand how the Given ended up perpendicular.

https://youtu.be/RuhETd0hTyU

I have to do some thinking on this, I'm not a ship handling expert, but.i believe the hydrodynamic forces created by a ship running close to a bank would tend to push the bow away and draw the stern in which is the opposite of what we see.

 

[TugboatEng]

This graphic has been posted to show just how aground the ship is. The white is dredged channel, the blue is shallow water.

The pro mariners are still specultating about a loss of electrical power.

Positive news, the stern has been floated free. However, it seems the bow has been holed. More speculation is that cargo will need to be removed. Removing ballast to float the ship makes it dangerously unstable.

 

[hokie66]

There is no overtaking in the Suez Canal. It was bad luck that the grounding occurred in the single channel part of the canal. Further along, there are now northbound and southbound channels, which can be pressed into double duty.

 

[LittleInch]

Tug, that's a great find. I was wondering if the canal wasn't even sided as the stem seemed to sit lower and I saw a photo showing one ship behind it moored up against the bank.

But if the ship is billed that's a big blow for them. Haven't seen an update on the dredging work recently.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.