What's the Difference Between a Barge and a Narrowboat?

There are no working barges on the Thames anymore, so it does seem quite weird. We do think that's a good thing that we stopped people learning how to barge and getting them to do maps instead these days. Well, it takes just two years of training now and six months of local knowledge training, which is... But then people just trashing barges into each other. It's ridiculous.