Sure. The point is that this isn't a particularly significant "first" (as the original headline claimed), it's an incremental advance in tunnelling technology. If James Brindley had been able to build Harecastle to Mersey Flat dimensions, he would have done. But tunnels have steadily got broader, deeper, longer and air-draft-ier since Harecastle and Malpas. There was no sudden moment when someone invented and built the ship tunnel.

(Incidentally, the "general definition" you cite is one used by the US Naval Institute, but not universally recognised. As the former editor of a monthly news-stand boating magazine it's certainly not one I've ever used. In the UK, for example, you can legally define your small boat as a ship by signing up to the Small Ships Register.)