Where to advertise (UK Boats Only)

You could try advertsing in the following places:-

Don't forget to add your own boatsell/yourboatname.html URL.

Free or nominal commision based on a sale only

Towpath Talk (Good for Narrow Boats and free for a month)
Facebook Market Place (Quote narrowboat as one word)

For a fee

Boats and Outboards (Not really for narrow boats)

Worth Considering but will charge

Waterways World (Good for Narrow Boats)
Canal Boat (Good For Narrow Boats)