Good to know. Unexpected. Soot tends to be behind the direction of primary travel, but apparently there are exceptions.
Safe to say that no damage is being shown in any of those pictures, regardless.
I've never see soot come from a discharge port though. I think this is likely the ship. Interesting point too is the pneumatic fenders handing from the aft port side. The soot points to something happening below decks. I could have wiped out the heat exchanger for an emergency generator or even a main engine. Such a rupture in that case would most likely produce soot normally not seen. The account of the thud says likely dud or fragments from a near miss one of the two. Then again it may not be soot we are seeing but good old fashioned crud jarred loose from a near by explosion or the ship being jarred by a dud.
Keep in mind when I say heat exchanger I mean the salt water radiator for the engines. They use water cooled radiators which are referred to as heat exchangers. If this is the case the engines cooling systems may be capable of cross connecting and one exchanger serve both.