Aiyo...how come my name came out here :lol:
Glad ur doing a sub there, CP....last time u racun me do figure, haha now ur turn do ship :D
Ill try to help..this how i normally do it, but of course there is much more expert ways by the sifus....so far mine work for me la...
This method is modification of that used for ship. Its more for a boat in wartime , cos peacetime will be spick and span. You might want to decide if u are presenting the boat at the beginning of a cruise, during or end. It will look neat after the refit, but very tired when it comes back.
Ship/sub have many different materials...wood, steel, aluminium, rubber...each one is different...so u need to do decide on strategy first. Also, close study of reference pics to see how weathering occurs on that particular type of boat.
1. Base coat (paint texture, chipping etc shud be adjusted here), future - I usually future the whole hull to give more protection for the wet wash later. Not critical if ur using acrylic/water colour
2. Any decals applied
3. Flat coat
4. Streaking can be done with airbrush...thinned black/grey/umber to give patchy effect to paintwork
5. Enamel/oils pin wash with burnt umber/sienna/black of deck detail, rivets, holes etc
6. Enamel/oils wet washed with lotsa turpentine/mineral spirit to blend. While wet, add in more "kau" mix of sienna and umber in certain places for rust marks. Important is need to study how the water flows over the hull and where it comes out eg drain hole.....some places more rusty than others eg railing, welding points, bolt head, anchor etc. Maybe some green for sea algae growth on waterline. Guns, instruments, radar etc should be well maintained, so not rusty. Also note that underwater part of hull should not be rusty (no air to rust), but I add some wash around seam lines to highlight them
*Step 4-5-6 can be interchanged/repeated depending on situation. Rust streaks can be airbrushed also, but I prefer wet wash style..more control
7. More stronger rust using pastel or pigment....orange for new rust, darker for older rust. Apply sparingly here and there only, again choosing the spots eg weld seam, railings
8. Weathering of non-steel parts incl wood, cables, prop, rubber etc with wash/pastel/oils
8. Some drybrush can be added here and there to suit your taste to bring out details
9. Final matt coat
Cos I use a "wet wash" method with lot of enamel thinner, might be danger to paint job. Make sure well protected with future/varnish, but generally its pretty safe for acrylic. Lacquer paint even more tough. Acrylic/water colour wash is least risk of course, but they dry too fast
Rust should be controlled....not overkill....risk of making it look like a rusty tube. At the end, this kind of effect is fine for my average level standard (my previous U boat built):
For sure, different people will have different taste and higher levels on the finishing...
Hope my 2cts helps, maybe the expert have more ideas....I find ship weathering far more interesting than aircraft/AFV...but thats me ;)