Actually that marking is due to the damage caused by the ships anchor as it is housed in the hawse pipe. Most of it is mud which has been washed down the hawsepipe as the focs'le head gang wash down the cable and anchor as it comes up from the bottom.
yeah let's add that texture to it, makes more alive more of a working class vessel, i mean how come every ship that i see in real life has something like that but the ships over here stay "perfect" not even a scratch, thats what i like about a ship all those stains, thats what makes simulation enjoyable for me, it's getting boring seeing the ships perfect after awhile, but rust me i can't get enough of ships when they contain rust marks around the hull in various places muddy thing at the anchor like Sherpa, thats real ship simulating man