Aha !
Very good question . Now here’s how I solve that . The U.S.S.OZBOURN D.D.846 when arriving at Bremerton and the water drained from the drydock looked like someone sanded a lot of the red and some of the boot stripe off , or nearly so .
What most folks are NOT aware of is this .Salt water in it’s natural state i/e the Atlantic and Pacific and other oceans and seas is Extremely corrosive to a ship . It’s just like driving it through a Sahara made of water . So you get that abrasive reaction on those surfaces exposed most to it .
That’s why , If I do a full hull ship I mostly do Pristine Museum types . Once in a while I do the whole thing heavily weathered from Keel to Truck but it’s rare .
The best example I can give here is the famous sailing ship Cutty Sark .She looked , when new , like she had a copper bottom .When in fact when she went in for re-fit it was a tarnished bronzy color .Why ? She wasn’t sheathed in copper , rather Muntz Metal which is a whole different animal in salt water !