[jcgrillo]

> German police were investigating an incident at a Hamburg shipyard where several dozen kilograms of metal shavings were dumped into a corvette-class vessel's engine system.

Italics mine, and holy crap that's a lot of metal shavings.. like multiple 55gal trash cans' worth.

[froh]

that's not correct

several dozen is not several hundred

1 dozen = 12

55 us liquid gallons = 208,198 litres

the densities of metals are higher than that of

water ca 1 kg/l aluminum ca 2.7 kg/l steels and iron 7.5-8.5 kg/l brass 8.5-9 kg/l gold almost 20kg/l

several dozen kg is half a 55gal worth, maybe one...

EDIT for shavings:

https://www.mollet.de/info/schuettdichte-und-schuettgewicht....

iron and steel chips / shavings still are about 2 kg/l

aluminum is 200g / l

so one 55gal trash bin of aluminum shards is still about 40 something kg, four dozen.

thus for aluminum and aluminum only I stand corrected, it may be multiple trash bins.

[gmueckl]

You're mentioning the densities for solid bulk materials. I'd expect shavings to be quite loose and trap a lot of air. Depending on the exact type and shape of the shavings, I can imagine a huge volume increase compared to the bulk material.

[hx8]

You also have to imagine the size of the engine the shavings were deposited into. Assuming it's the new German corvette class (K130 Braunschweig), they are powered by two MTU 20V 1163 TB93 engines. Each one has about 240liters of displacement. This means each engine has about 4 55gal bags worth of cylinder volume, plus turbochargers, fuel pumps, etc. It's unlikely that ~1/5th-1/10th of the entire volume of the engine was consumed by shavings, mostly because 1/50th is probably enough to ensure major permanent damage.

Interestingly enough, the engine is produced by a company owned by the Rolls-Royce holding company, so in a meaningful way the British are helping the Germans produce warships. In the first half of the 20th century the British would have been prime suspects of the sabotage.

[jcgrillo]

1 shaving is enough to do catastrophic damage. Bigger engines don't have bigger clearances ;)

[hx8]

So why did they use kilograms if grams would have worked fine?

[jcgrillo]

Higher probability of success. With 1 shaving it could make it to an oil filter without lodging anywhere critical (like in a main bearing oil gallery or something). With a huge number of them the likelihood of clogging oil galleries and overwhelming the filtration system is very high. Also, the secondary point of the sabotage is to be detected. Even if the engine doesn't grenade itself through the hull of the ship, when they discover widespread contamination in the lubricating oil they'll have to remove and completely disassemble every single part of the engine and lubrication system. Effectively a total rebuild. So "no permanent damage" is really a very rose colored way to frame it. The cost is roughly the same.

EDIT: a super devious way to do it would be with very small magnetized filings. It would be incredibly difficult to rid the engine of those, even completely disassembled.

[jcgrillo]

A trash can of metal shavings is mostly filled with air.

[Towaway69]

> 55 us liquid gallons = 208,198 litres

I was also confused but could be German usage where comma and dots are swapped. The German 208,198 is the same as the English 208.198

Conversely the English 1,000,000 is 1.000.000 in German! Very confusing.

Remember Germany is still the place where you say four-and-twenty for twenty-four …

[lucumo]

> Conversely the English 1,000,000 is 1.000.000 in German! Very confusing.

Well, yes. But it's mostly the Anglosphere being weird again: https://commons.m.wikimedia.org/wiki/File:DecimalSeparator.s...

I personally like to use thin spaces or apostrophes as a thousands separator, precisely to avoid the language confusion. I also try to avoid three decimals going for 2 or 4 instead, but you can't always do that, because it changes the content.

> Remember Germany is still the place where you say four-and-twenty for twenty-four …

As someone from another language that does that: agreed. It gets even weirder with 124: one hundred four and twenty. Middle-endianness is silly.

[resist_futility]

It's pretty even on both sides of dot and comma

https://en.wikipedia.org/wiki/Decimal_separator#Conventions_...

[Towaway69]

Thanks for that, I didn’t know it was that common. Would be interesting to know whether there was ever an attempt to find a globally consistent form.

If you look at the image, Antarctica has “data unavailable” - seems we still don’t know what the penguins use! /s

[card_zero]

For the thousands separator, the International Bureau of Weights and Measures (based in France) recommends the use of a space, and as a result this is used in France.

[Xixi]

Commas and dots being swapped is fairly common on continental Europe: I think it's the case at least in Germany, France, Spain and Italy. Probably other countries as well.

Since we're talking about numbers, in France we used to count by blocks of 20, and the usage somewhat persists to this day: so, for instance, 72 is read "sixty twelve" (60+12), 81 is read "four twenty one" (4x20+1), and 96 is read "four twenty sixteen" (4x20+16). Mind bending for the poor French learners...

[elric]

> Remember Germany is still the place where you say four-and-twenty for twenty-four …

That's a weird remark to make. Lots of languages do that. And if you want to talk weird numbers, try Japanese with their 10k grouping (e.g. 100k is 10 10k, juu man, 1M is 100 100k, hyaku man, etc).

[Towaway69]

Humans are truly creative when it comes to counting.

Regularly switching between four-and-twenty and twenty-four, I find it annoying and hence a slight frustration might have sipped through.

[dkga]

Laughs in Danish!

[sllabres]

this usage of the decimal separator is not a German thing only [1] and globally not very consistent.

One third of the world seems to use ".", the other third "," and the others decides with own rules or have own symbols. (Space, "'" and "·" and "_" in many variants).

[1] https://en.wikipedia.org/wiki/Decimal_separator#Conventions_...

[card_zero]

I like the idiosyncratic Indian digit grouping where you start with a group of three and group the rest of the number in pairs, it's very creative.

[jcgrillo]

Yeah I deleted that when I realized my misinterpretation. I was thrown by two different styles of notation in the same post.

[froh]

apologies for the cut n pasted confusion :-D

[jdietrich]

Also, the alleged incident happened at a shipyard - finding dumpsterloads of metal shavings there is like finding sand in the desert. It's plausibly an opportunistic attack by a spy who was already in the facility rather than a planned operation.

[cenamus]

Shavings are way less dense than solid blocks of metal.

[vm]

This analysis reminds me of this classic, albeit crude, joke from Silicon Valley…

https://youtu.be/Tx3wDTzqDTs?si=gybpX8Gha4nJ2Dve

[Sontho]

Still it's a lot.

[D13Fd]

> holy crap that’s a lot of metal shavings.. like multiple 55gal trash cans’ worth

I don’t think so. A 55gal Tran can full of metal shavings is probably several hundred lbs. 2 dozen kilograms is only about 53lbs.

[hx8]

It really depends on how corse the shavings are, if you do any work to compress the metal shavings, and the density of the alloy. However I think you're right, because 53lb of steel is only about 0.1ft^3.

[jcgrillo]

I assure you it isn't. I've lifted them many times. I'd say 75-100lbs is normal, depending on the distribution of metals (obviously steel is heavier than aluminum for example).

[lostlogin]

That sounds really unlikely. Is there some that is more dense?

[jcgrillo]

IME they're really not all that dense. When chips come off a lathe or mill cutter they are curled and have small serrations in them where the sharp edge cracked as it was curling. So they don't pack well. Each chip takes up a large amount of 3D space and they interlock really easily--they don't slide past each other.

[froh]

ah that's where you're coming from (see my other comment)

https://www.mollet.de/info/schuettdichte-und-schuettgewicht....

iron and steel chips still are about 2 kg/l

aluminum is 200g / l

so one 55gal trash bin is still about 40 something kg, four dozen.

so for aluminum and aluminum only it may be multiple trash bins

[lostlogin]

This still sounds hard to sneak into a warship’s oil system though.