As with the previous war, there was a shortage of boatmen as the younger ones left for the armed services, though canals were, to some extent, a reserved occupation. In the First WW they created a Canal Transport Battalion, with other battalions set up to help at docks and other transport bottlenecks. In the Second WW canal companies tried to get Irish labour. Although initially successful, many of the Irish soon left for better paid work. Quite significant tonnages were carried by canals, and they were useful in getting imports away from docks where they were more likely to be bombed. In Liverpool, a new warehouse was built at Gorsey Lane, Netherton, for goods brought out of the docks by lorry for onward distribution by canal - you can still see the concrete wharf edge. If you are interested, I wrote an article on the subject for the Boat Museum Society's Waterways Journal No 5, which is still available from them, and I have some text at http://www.mikeclarke.myzen.co.uk/Wartimecanals.htm