Note: A tug pushing is considered a power driven vessel. Thus the Sail boat would have right of way. Now in a channel both vessels are to suppose to keep to the starboard side of the canal. But there have been times where I've seen vessels on the wrong side of the canal, far to many times.
For a tug to have restricted Manuverability, she would have to be towing astern and the construction of the tow would need to be taken into consideration, else wise she is a power driven vessel.
But until we have the facts on what really happened, we can't make a judgement call and learn from somebody else's mistakes. (the best way to learn) So we have to commiserate on the lost of a beautiful schooner and be thankful that no one was lost in this accident.