painting a 40ft motor yacht

The topsides ARE the sides of a boat. The bit between the waterline and the gunwhale.
The top of the boat is the deck and superstructure.
Sounds like n.herring is confusing what the topsides are too.
Worth getting the name of you boat parts right if asking for quotes or you may be disappointed.
No wasnt confused just covering all angles as my quote included bathing platform and not sure if that would be in topsides. I did mention super structure as a separate item!
 
Yes it was a colour change

Worth noting that after a colour change, the slightest chipping of the outer painted surface will expose the white gelcoat underneath.
Even the best polyurethane paint is a very thin layer, and for example you choose a dark colour, damaged/worn areas will show up dramatically.
White on white isn’t a bad option, or like Mr Googler says, wet sand and a good cut and polish by a skilful operator.
 
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