We were transiting Charleston Harbor at the time and listened to this transpire over the VHF
Vessel reported it was outside the harbor near the channel. Reported hitting a submerged piling. Never called MAYDAY, merely reported they were taking on water
The power vessel Pay Dirt was within site and reacted quickly to help. On radio
they told Ryota that if they didn't change course they would hit the sea wall. Ryota responded they had no power. Pay Dirt transferred occupants and took line to tow the boat. They had to cut it free shortly before she sank. They reported seeing her go down by the stern.
USCG was in frequent contact but it was after vessel went down that we saw a Coastie but speeding in that direction.
The hole must have been major because it went so fast.