Is that ship still stuck?

Re:Is that ship still stuck? by Gustomaximus on Friday March 26, 2021 @12:35AM (#26588786)

This was my though, winchers/dozers etc pulling back the angle it went in on a high tide. Of all the solutions suggested this seems the simplest and easiest materials.

For anchor points they could easily weld additional steel plates/rings at numerous points on the hull for a many lines spread out.

Maybe place some cables under the front section attached to airbags. It would not lift it off the sand but may help with downward pressure on the pull back + the excavator work.

Also cant you vibrate/aerate sand to make it have a liquid effect? Might help pressure but no idea how that could be done at scale required... winches and cable seems easy to access fast.

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Re:Is that ship still stuck? by azalemeth on Friday March 26, 2021 @08:17AM (#26591155)

Just an order of magnitude viz-a-viz a winch:

-- the Ever Given has a mass of ~220,000 tons (2.2e8 kg)

-- let us very conservatively assume that it is a homogeneous block, 1/3rd of which is on sand, 2/3rds of which is on water

-- the Coulomb coefficient of friction for steel on sand is a very complex function of sand composition and size, but roughly it's about µ=0.5 and F=µR [1]

-- For the 2/3rds of the ship that are in the water assume that it moves frictionlessly in an inviscid liquid (not true at all else ships wouldn't have huge engines!)

-- You therefore need to apply a net tension of ≥0.3 x 0.5 x 2.2e8 ≈ 33 MN to a wire to have a remote chance in hell of accelerating the ship backwards

-- This is about twice the thrust of a Space Shuttle solid rocket booster at liftoff.

[1] https://www.jstage.jst.go.jp/article/sandf1972/26/4/26_4_139...

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Re:Is that ship still stuck? by wildthought on Saturday March 27, 2021 @05:33AM (#26601111)

The weight on sand equals the weight of the portion of the ship that has been raised above sea level by the collision. The bow appears to have been raised, but not the stern. The lift is by about 10% of the ships height (or less), so 5% on the average of the ships length. That cuts the above estimate by a factor of 6. The remaining required force could be provided by a number of winches of a pull of 1000 tons each operating from the opposite bank of the canal and pulling in the direction opposite to the ship. Tugs would then have to turn the ship straight as soon as it starts getting afloat.

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