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Kind: captions
Language: en

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Behind me is HMS Defender, one of the new
generation of Royal Navy ships. It is an incredible

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piece of engineering, capable of taking out
a small drone at 40km distance, capable of

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tracking 2,000 targets at once.

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'Cos it's a destroyer, and it is meant to
defend itself and the rest of the fleet by

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taking out incoming missiles before they even
come close. It is a masterpiece of modern

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warfare engineering.

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[MUSIC: Rule Britannia]

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But like all big ships, it has a design flaw
that you really can't get around -- as long

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as you're building something out of steel.

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If you take that much metal, and put it through
a big magnetic field -- like, say, the Earth's,

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as it sails around -- then it's going to start
picking up magnetism. It's going to start

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diverting compasses. It's going to start being
detected by magnetic mines, which were developed

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during World War 2 and afterwards to home
in on any big source of magnetic signals -- like,

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say, a ship that's been sailing for a while
-- and detonate next to them.

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We're talking sea mines here, by the way,
not land mines.

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So how do you defend against that? Well, nowadays
you use very complicated degaussing equipment

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on board a ship. But in the past, you used
to drag a 2,000 amp electrical cable down

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the side, or set up an enormous degaussing
coil that is bigger than the ship itself,

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and -- well, do the same thing that you used
to do to CRT monitors when you pushed a button

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and they went 'dong' and distorted for a while.

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But what if you want to get close to a mine?
What if your ship's job is to get rid of mines,

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and you need to get close enough to spot them
without setting them off?

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Docked just downriver from Tower Bridge is
this: HMS Middleton, a Hunt-class mine countermeasures

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vessel. It's a minesweeper, bascially, which
means it can tell how many mines are in adjacent

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grid squares -- no, I'm kidding. It seeks
out and destroys mines.

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But it's able to do that without the mines
detecting it and detonating it because this

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is not made of metal.

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This ship is made of glass-reinforced plastic.
It's able to find and destroy mines that are

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hunting for magnetic things because, well,
it's not made of anything magnetic. It's just

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a plastic boat.

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Sounds terrible when I put it like that, but
well: this class of vessel can do more damage

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to one specific threat
than anything else in the Royal Navy.

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