[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.

[sitkack]

Nailed it.

This was a huge security screw up, you have to draw your security barrier and they left this huge asset on the wrong side of it. If only the followed Gauss's Law.

[gmueckl]

The ship hasn't been put into service yet. It's still with the shipbuilders, where I suspect that security is much weaker than on a navy base.

[M95D]

> 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.

Just heat it.