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Comment by learningwebdev | Hacker News Reader

> The breakthrough in the rescue attempt came after diggers removed 27,000 cubic meters of sand, going deep into the banks of the canal.

Impressive. That's around 55,000 metric tons of wet sand, or a bit more than the mass of the Titanic.

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And given the sand density, much larger volume.

Boats don't have a high density. It has to be lower than water or they won't float.

The Titanic does not float.

Fair cop.

I was trying to hint at the fact that "boat density" is not a very well defined concept.

Hehe, but still, it is a very funny remark and it points to a large assumption in the gggp: that all boats will float. They do, right up until you smash them into icebergs and such.

On a technicality such an event changes their density considerably, assuming we take that to mean 'everything inside the volume circumscribed by the hull', after all, whether you insert all that water through a hole in the front or in the top doesn't really matter, as long as the air gets displaced that will do the job nicely.

Yup, that's what I meant although it is not exactly "volume of the hull". The boat density should be something like "density as you would calculate it for any solid object" plus "all air below the water line". So solid parts always count and air only counts if its below the water line.

This way Titanic counts as just a heap of steel (and doesn't float) and Ever Given counts as steel-air mix (and floats).

How to tell if your ship has sunk: the waterline is above your superstructure.

Is this due to U.S. military involvement? I remember reading they were sending dredging experts.

Even in normal operations the canal is being dredged continually, since it's basically a channel dug into sand that's continually dissolving in the water. Check out the cross sections here: it's much wider and more shallow (gradient up to 4:1) than you might think.

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

They have a fleet of ~13 dredgers of different types:

https://www.dredgepoint.org/dredging-database/owners/suez-ca...

The Dutch company Smit (part of Boskalis) was hired for this job.

This isn’t a Hollywood movie. Another country is actually considered to be the expert in such matters.

Why a snarky response to a harmless question? The person asking the question didn’t say anything about US expertise or Egyptian expertise.

It’s considered condescending to send help in dire situations?

Damn, everyone is on the edge these days.

really... negative 4 votes for a legit question... hmm.

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