Behind me is HMS Defender, one of the new generation of Royal Navy ships. It is an incredible
piece of engineering, capable of taking out a small drone at 40km distance, capable of
tracking 2,000 targets at once.
'Cos it's a destroyer, and it is meant to defend itself and the rest of the fleet by
taking out incoming missiles before they even come close. It is a masterpiece of modern
warfare engineering.
[MUSIC: Rule Britannia]
But like all big ships, it has a design flaw that you really can't get around -- as long
as you're building something out of steel.
If you take that much metal, and put it through a big magnetic field -- like, say, the Earth's,
as it sails around -- then it's going to start picking up magnetism. It's going to start
diverting compasses. It's going to start being detected by magnetic mines, which were developed
during World War 2 and afterwards to home in on any big source of magnetic signals -- like,
say, a ship that's been sailing for a while -- and detonate next to them.
We're talking sea mines here, by the way, not land mines.
So how do you defend against that? Well, nowadays you use very complicated degaussing equipment
on board a ship. But in the past, you used to drag a 2,000 amp electrical cable down
the side, or set up an enormous degaussing coil that is bigger than the ship itself,
and -- well, do the same thing that you used to do to CRT monitors when you pushed a button
and they went 'dong' and distorted for a while.
But what if you want to get close to a mine? What if your ship's job is to get rid of mines,
and you need to get close enough to spot them without setting them off?
Docked just downriver from Tower Bridge is this: HMS Middleton, a Hunt-class mine countermeasures
vessel. It's a minesweeper, bascially, which means it can tell how many mines are in adjacent
grid squares -- no, I'm kidding. It seeks out and destroys mines.
But it's able to do that without the mines detecting it and detonating it because this
is not made of metal.
This ship is made of glass-reinforced plastic. It's able to find and destroy mines that are
hunting for magnetic things because, well, it's not made of anything magnetic. It's just
a plastic boat.
Sounds terrible when I put it like that, but well: this class of vessel can do more damage
to one specific threat than anything else in the Royal Navy.
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