When you glass the 'completed' object still retains the weave of the glass. This needs to be filled, usually with filled resin - you sadly then need to fair it.. It then needs filled again, because it contained air bubbles, so you need to sand again - you can do this as long as you like or until you are happy. Once you have it smooth, to your satisfaction, you then spray paint, with a 2 pack (or that is what I used).
Neat resin is terrible to sand - its exceptionally hard - but fill it and it becomes easier. Once you get near the final finish you are simply trying to fill any air holes (fillers entrap air quite easily) and produce a hard exterior surface (to withstand knocks and bumps) and I used a small domestic roller and neat resin, just very thin layers (as this means fairing (sanding) is minimised.
A lot of the sanding is mechanical, you can use any of a number of hand sanders. Its not difficult. Much depends on the quality of finish you want to achieve.
I've seen many home built catamarans, there is a whole industry here supporting them (Harken, I think, did a survey about 10-15 years ago and there were about 500 home builds in progress, from about 35' to 50'). Some home builds are fantastic, too many look awful. But a 40' cat is a big project. You need patience.
I mentioned earlier - speak to a foam supplier, go and see them. Its not difficult, you can produce amazing results and you can make exactly what you want (there are no restrictions caused by the materials).
Our Godpod is on the starboard side, so is asymetrical. It is open into the cockpit, steps up and into it but we have a 'lift out'door to exit to the deck.
Jonathan
