Pipster, you say the paint was on the boat for weeks but still it left marks whilst in the stand!
How bad are the marks? Do they look like scratches or do they look like something melted?
Scratches..... Have you been grinding near your stand?
Melted (for want of a better word) ... After a reasonable drying time this shouldn't happen which suggests a chemical reaction. Not between the stand but between paints. This reaction will allow the surface to appear dry but between layers it's still soft. Any weight applied then causes marks.
Are you using different makes of paint?
Are you mixing different types of paint.
Are you mixing one make/type of primer with another make/type of paint.
The reason I am asking is because when I painted my boat I used all the same kinds of acrylic rattle cans. All the same make. I sprayed gray primer onto the hull in the sunshine, left it 15 mins
and then painted the colour. I left it 24hours to harden then did the second colour, another 24hours and the final colour. After a further 24 hours I applied a same make clear lacquer. The result is a hard layer of smooth paint that doesn't mark in the stand. The stand is a wooden stand with foam pipe insulation. (See Lena my first boat build thread)
I feel the problem is A, an incorrect mix of paints or paint types or B, (less likely) a bad tin of paint. Good luck in finding out and sorting this annoying problem..... U2