Narrowboat
A narrowboat or narrow boat is a boat of a distinctive design, made to fit the narrow canals of the United Kingdom.
In the context of British Inland Waterways, "narrow boat" refers to the original working boats built in the 18th, 19th, and 20th centuries for carrying goods on the narrow canals (where locks and bridge holes would have a minimum width of 7 feet (2.1 m); some locks on the Shropshire Union are even smaller). The term is extended to modern "narrowboats" used for recreation and more and more as homes, whose design and dimensions are an interpretation of the old boats for modern purposes and modern materials.
Terminology
Purists tend to write the term with a space (narrow boat) when referring to an original (working) boat or a replica, omitting the space when referring to modern canal boats of around 7' beam and used for leisure including residence. The single word 'narrowboat' has been adopted by authorities such as the Canal and River Trust, Scottish Canals and the magazine Waterways World to refer to all boats built in the style and tradition of the narrow canal locks.