Narrowboats are all painted by hand using enamel paints, similar to coach paint. Good old fashioned stuff with plenty of volatile solvents.
The paint is brushed or rollered on, and then 'laying-off' with a dry brush. (brushing gently one direction then at right angles). The finish is near perfect with no brush marks.
Back in the early-1990s, I brush painted my Toledo with ICI Permobel Mimosa yellow together with "hammer-finish" black Hammerite. The ICI Permobel gave a reasonable finish, but I would have preferred an longer "wet-edge" time.
Nigel A. Skeet
Independent tutor of mathematics, physics, technology & engineering, for secondary, tertiary, further & higher education.
Upgraded 1974 Triumph Toledo 1300 (Toledo / Dolomite HL / Sprint hybrid)
Onetime member + magazine editor & technical editor of Volkswagen Type 2 Owners' Club