If hyperbolic metaphors were true…

Today I thought I’d examine a couple of hyperbolic metaphors on the basis of their being literally true and see where that got me, scientifically. I mean, what is a hyperbolic metaphor worth if science can’t say something about it, really? Check this out.

‘Enough food to sink a battleship’

How much food would sink a battleship? We have to suppose it means enough food to overload the vessel until it sinks, but that doesn’t define a figure because battleships have been built to all sorts of displacements, from the 10,000-ton British jobs of the late nineteenth century through to the 70,000-ton Japanese monsters of the Second World War. Obviously the weight needed to sink one will vary.

HMS Camperdown, a British battleship of about 10,000 tons launched in 1885. Picture via Shipbucket, by DarthPanda, CC Attribution Non-Commercial 4.0 license.

What’s less obvious is that even if we defined a standard displacement – let’s say 35,000 tons, which was a figure agreed by treaty during the inter-war period. Even then you can’t say, because ships sink in two main ways: loss of reserve buoyancy, or loss of stability (typically, capsizing, or more rarely sinking by the head or stern, which leads to loss of reserve buoyancy). Reserve buoyancy is the amount of extra buoyancy designed into a ship beyond what it needs to stay afloat when loaded. It varies depending on the load and can be lost if the ship floods. Sinking by bow or stern involves loss of stability, which takes less off-centre weight. Capsizing requires even less off-centre weight, which is why captains are always concerned when their ship takes on a list.

Prince of Wales a few minutes before sinking, taken from HMS Express. Sadly, over 300 lives were lost when she went down. Public domain, via Wikipedia.

We’re still talking thousands of tons here. HMS Prince of Wales, for instance, a British battleship sunk off the Malayan coast by air attack in December 1941, sank by a combination of lost reserve buoyancy and lost reserve stability, eventually coupled with free-surface effects (slopping in large compartments). The amount of water on board when she sank was estimated at 18,000 tons, which was a significant figure when you consider that the ship was designed to a standard displacement of about 35,500. How much food is 18,000 tons? I believe it’s less than is needed for a typical kids’ birthday party, but might be enough for a standard First World family Christmas dinner. It could also feed the hungry people of a small Third World nation for a week.

‘Not enough room to swing a cat’

The problem here would be getting the cat to sit on a swing in the first place, and again the answer depends because the scale of the swing isn’t defined. Or maybe the phrase refers to picking a cat up and swinging it around, which really isn’t advisable because (a) it’s cruel to the cat, and (b) the cat would likely decide to shred the arm of its disobedient servant who was swinging it. But assuming you were so mean as to do so, there’s still no actual answer because the nature of the swinging isn’t defined. Does it mean extending the cat at arm’s length and doing a 360 degree pirouette? If so, given the average human spine to fingertip distance of perhaps a metre, plus the cat’s dimensions of (say) 0.25 metres, the phrase refers to a space less than 2.5 metres across. But who can really say? And, just for the record, don’t try.

‘Raining cats and dogs’

This is an extremely unlikely proposal because it assumes that cats and dogs are somehow falling from clouds in the sky. It’s certainly possible for objects, even significantly heavy ones, to be lifted up by wind and thrown some distances – the energies developed by really strong winds are very high by everyday human measure, and this happens all the time in tornadoes. There are records of waterspouts lifting fish from the sea and depositing them a short distance away. I’ve seen at least four documentaries suggesting that this tornado-lift problem keeps happening to whole swarms of sharks. Well, I think they were documentaries anyway.

But to assume that cats and dogs might do the same is a stretch because you first have to assume a concentrated supply point for the waterspout or tornado to pick them up from. But supposing that a tornado ripped through the local SPCA and lifted the contents, it is technically possible that it might rain cats and dogs nearby. And, of course, also vets, bits of building, and so forth. So I think the phrase needs adjusting to be ‘Raining cats, dogs, cement blocks, wood, roofing tiles, furniture, vets, veterinary equipment, and other stuff’.

So there you have it. And who says hyperbole can’t be scientific?

Copyright © Matthew Wright 2019