Don't sand it as the dust can get into your lungs even with an N95 mask. Instead wear a good mask but use a wire brush in an electric drill to remove loose paint. Then undercoat it and paint it. It's inside so weather-shielded right?
"Rupturing fibres" is an irrelevance as any fibres you pick up would have been loose anyway and the paint will lock them down as it dries.
You could of course remove loose paint and stick cheap carpet over the hull thus removing at one stroke a cold interface creating condensation oplus adding insulation and improving the appearance.
Wire brush for sure but I would go with a cup brush in an angle grinder as much easier to use than a drill (it helps that I have a choice of grinders to hand), the twisted wire cup brushes last much longer and don't throw so many wires at your eyeballs but do wear safety glases with spinning brushes. How about a coat of flowcoat instead of paint so any loose fibres are properly bonded back in, then carpet over with a bathroom type carpet as they are better with moisture and easier to clean, you would need to wash over flowcoat before glueing as it has wax added to help it cure properly, it's what I used in the engine bay of my RLM31 when I replaced the engine bearers.
If it's up in the bow look out for some numbers in permanent marker, I believe it's how they were marked from the factory and should give a clue to the age of the boat and worth noting down before covering over, I only found this out after covering over in my second norman so never seen it for myself.