Other factories were added in Royton and Heywood, and the business expanded into manufacturing windows and windscreens for both Norman Boats and other customers under the name of North West Windows Ltd at the Heywood factory.
Norman Cruisers were in the top three largest pleasure boat builders in the UK, Westerley Yachts being the biggest.
Principal markets (in order of volume) were the Netherlands, Germany, Norway, France and Sweden.
Boats in the Netherlands were imported by Internaut of Rotterdam and were sold under the name of "Inter", hence the 20 was the Inter620.
Some moulds were re-built and when the business finally ceased, these were sold and marketed under other names, such as the Atlanta 24.