Denise, I've been on the DUCs, not the one in Philly but the same company. They're quite sufficient for the waters they operate in, quite enough freeboard, and there are active bilge pumps running in them. (Much better than the ones in our boats, yes.)
Nothing will survive a direct hit by a barge, so the seaworthiness of the DUCs isn't an issue here.
And everyone here SHOULD be aware that even if the commercial vessel is keeping a proper watch, any ship, any tug+barge, has a HUGE blind spot immediately in front of their bow. They may not be able to see anything for 1/4-1/2 mile directly under their bow, and that's one reason so many commercial captains get ballistically PO'd at racers who cut inside that dead spot, routinely, figuring there's plenty of seam room. THERE ISN'T, THE GUYS CAN"T SEE SQUAT UNDER THE BOW.
So given where the DUC was, you can expect a disaster. The only real questions are:
1-Was the tug keeping a proper bridge watch, that might have seen the DUC enter the danger zone? (Probably not, since the tug did't sound 5x on the horn.)
2-Was the tug keeping a proper radio watch, to receive the mayday calls from the DUC? If the DUC made them? Again, probably not.
3-Could either party have taken any action to avoid the collision? On the tug's side, probably not because of limited manueverability, UNLESS a proper watch would have had adequate time to respond.
On the DUCs side...There may be full liability. The DUC driver may have drifted into the channel by fast current, OR he may have been trying to cut ahead of the barge when he lost power. Two very different results.
But the range of options, the range of possible mistakes, is fairly small and I'd expect the court of inquiry is going to get ot the bottom of this one quickly. If the tug skipper takes and sticks to the fifth amendment...that will point to not keeping a proper watch, and that will damn him.
Give it six months, we'll see.