She either just completed or is getting ready to bunker. See the fuel bags hanging under some of the vents? There are no spill trays on the invader class tugs, so the bags are placed on the vents of the tanks that are being filled. The problem is, by the time you see that a bag is filling, you won't have time to stop the bunkering before you have a spill.

Good picture, nice tug too. Does Crowley often work in Philadelphia?