Olav,
I painted the rough grey fibreglass areas an off-white colour. The
underside of the main cabin top is very smooth white fibreglass and
mine did not need attention. I scrubbed the area to be painted with a
T.S.P. solution and an abrasive Scotch Brite pad.
Painting the lighter colour brightened up both cabins a lot. I used a
house paint that covers extremely well and has a mold and mildew
inhibitor in it to discourage mildew growth.
I used this paint on my other boat last year and it is proving to be
very tough.
Here's the URL for the paint:
Zinsser - A trusted brand known for professional-quality primers, sealers and other coatings for nearly every surface. Wall primer, shellac, stain blocking technology.
www.zinsser.com
and a picture of the painted interior:
Hope this helps.
Peter
#1331 'Sin Tacha'