Are you seriously suggesting that my wife and I, despite being sensible and wearing life-jackets when on rivers, despite having an anchor ready at all times, and despite my having undertaken a VHF radio course, should not have navigated in recent years the following, in our very well-maintained 1992 boat, with its 40 hp Lister engine?
The Ribble Link, involving the tidal River Douglas and the equally tidal Ribble
The tidal Trent - many times
The tidal Thames - once from Teddington to Brentford and once from Teddington to Brentford, Regents canal to Limehouse, and tidal Thames back to Teddington
The Bristol Channel from Portishead Marina to Sharpness - with a pilot, who insisted upon Force 3 or less winds for our safety
.Narrowboats may have been designed for canals, but they are more than capable of cruising further afield, with the right precautions - for goodness sake, narrowboats have crossed the English Channel!
Oh, and I forgot the River Soar!