Watch BRM's (British Railway Modelling) Phil Parker demonstrate how to model a canal boat that's perfect for your model railway layout. www.world-of-railways.co.uk
There good little kits but if your after an accurate looking narrowboat there's only really the Skytrex steam natrowboat, it's easy to convert to a diesel or a liveaboard instead of a work boat using the likes of balsa or styrene
Good explanation and a neat model. Could I suggest adding a chimney for the cabin stove - usually near one of the forward corners of the cabin, a boarding brow (plank) and barge pole which are normally stored on the roof when not in use, a few roof ventilators, a stern guard rail (it’s a cruiser-stern boat) and fixed fenders fore and aft.