Since you are still in welding phase (pre basting) on the inside the most important action you can take right now is to make sure that no water can ever pool anywhere inside your
boat.
Combine this with a totally watertight
deck and it is technically possible that blasting and painting the inside is not totally necessary.
I would really love to have a
bilge lined with
stainless steel sheet. This place is practically impossible to get to after the
engine is in place.
Of course we live in a real world so I'd recommend considering the following:-
1) Any place that water can possibly pool (and it's probably not practicable to get them all) fill with thickened
epoxy resin after blasting.
2) The are several brands of high build epoxy paints used industrially. Check with the companies that make them as to their suitability for inside the boat. You'll be needing quite a bit so they should be very friendly.
3) You may be able to use the same paint inside and outside. Again check with the manufacturer as to whether their paint "blushes" and the best way to manage it. I try to use an alkaline wash (cloudy ammonia!) every time I'm top coating cured epoxy.
4) I'm not a big fan of two pack hull finishes. One scratch and it's never going to be the same again. If you can find a good
single pack enamel then future
repairs are going to be that much easier, and they are much safer to use.
4) If you can prime while the epoxy paint is "cheesy" (highly technical term) so much the better. Otherwise check with the manufacturer.
5) Below the water line I'd check what aluminium filled vinyl primers (Primocon is a common brand) are available. Again apply while the epoxy undercoat is "cheesy" and the antifoul may be able to wait till just before you go in the water.
6) Others may have different experience but I've found that Propspeed on the
propeller give a slight increase in
rpm and
hull speed. It could be my imagination but the stuff also seems to reduce the rate at which my anodes "evaporate".
This is also a good time to put in
electrical and
plumbing conduits. I'd suggest considering running most
electrical wiring (don't forget
antenna wiring -
radar,
VHF, AM/FM,
SSB,
AIS etc!). I'm seeing bundles of wiring an inch in diameter so some really generous sized conduit is going to make life much easier. I've run my
plumbing under the floor but even a few 1" water pipes mount up. Having big holes and even channels (to hold pipe) in place is going to make life much easier later.
And again in this unfortunate real world some decent sized holding
tanks are very useful. If you want to stay more than a couple of weeks in a sensitive area a couple of 200 litre polyethylene
tanks (one under the sole, one just under the
deck, connect with a
diaphragm pump) is going to help keep officialdom happier.
Don't forget a couple of decent sized water tanks either.
My experience has been that what totally stuffs paint under the waterline is electrolytic action. Drags big patches right off. On Boracay bitter experience has two huge anodes ether side of the bottom of the
keel, two smaller ones halfway up, two on the prop shaft, and two on the skeg and two on the
rudder. The ones on the skeg/rudder seem to vanish before my eyes but I don't like to go too big on control surfaces.
I've heard anecdotal evidence of skeg failure on
steel skeg/rudder
boats and in my opinion these always need to have anode protection.
I've started using
survey rated plastic through hulls after an unfortunate experience with a
stainless steel one. I've heard some
builder use thick stainless pipe welded the the hull with the other end threaded to accept a ball valve but your
designer would be the best person to ask about this.