To weather, or not to weather, that is the question..in my case, usually the former!
My latest purchase was a rather well build Our Lass II. The previous owner told me about his weathering technique, I thanked him for the primer coat! I am a bad person, but at least up front about it
Following a repaint from Southampton red and white, to Pompey blue and white ( honestly!!), it hit the water in a pristine condition. About a month into its use, it was weathering time.
Potted advice follows..don't use Humbrol Rust (113), it is not rust coloured..use 62 Sand, 63 Leather and 98 Chocolate, job done. Try to avoid dry brushing where possible, it usually looks like dry brushing! I usually use washes, or better still, a fine application with a pointy brush followed by brushing it out with a broad brush damp with thinners.
Sometimes dry brushing works.
Don't forget, dirt doesn't stop at the waterline..( I did the below waterline muck on Boll Weevil II using humbrol brown wash, slapped on with a half inch brush, in about a minute. This was then chased in a downward direction with a soft brush, damp with thinners over about another three minutes! ).
Mucky decks, a fairly clean vessel will still have mucky decks, including modern warships.
If you can see how the weathering was done, brush marks, splatter with a toothbrush etc, do it again, and do it better!
Rust mostly travels in a downward direction, not aft, at a 'go faster' angle, U-Boat boys!!
Not all dirty vessels are dirty. I have struggled to find a scruffy, big trawler in Portsmouth, since I started my weathering, however, the smaller boats in port are total rust buckets, good for reference....
Have good reference, don't just guess where the muck goes.
Practice makes perfect, don't be afraid to copy ( and of course improve greatly...) on other peoples work.
If you make a proper dogs dinner of a job, try weathering back over your mess with the original base colours, sometimes the best effects can come out of a total disaster.
Have a go, or don't, both camps certainly have there merits, it took me a while to decide to weather this model, instead of leaving it as was..