Vessel #2 was being towed by Vessel #1 to an island.   Vessel #2 was loaded with a ditch witch loader, rolls of sod and a load of dirt.  One of the passengers on board went to check a bilge pump on Vessel #2.   When he did,  he had to move the loader, which caused a weight transfer, which allowed water to come over the edge.  The bilge pumps could not keep up, or did not work, allowing the vessel #2 to take on water and sink.
Oklahoma City                 