I know this is maybe stupid but I'm watching Alien again and I'm at the end where Ripley activates the ships self destruct and it got me thinking. It seem's to be a recurring theme in Sci-fi films that huge spaceships have a self destruct function which when you think about it is pretty stupid as surely it could go wrong and just blow up at any time which would be annoying. So my obvious question is has any real military vessel ever had a self destruct capacity as surely blowing up something like an aircraft carrier would take quite a large explosion which would take up quite a large space for something that's only going to be used once for a split second. Again sorry if this is a silly question but as it's in so many fictional stories I thought I'd ask. I'm re-watching the Alien series in preperation for the new film.