RedactedNarrative: Operator 1 was operating Vessel 1 travelling E/B off the S/W corner of Tecumseh Island. Due to improper loading there was a dangerous reduction in freeboard in the starboard stern allowing water to enter Vessel 1 through the vent and over the gunwhale impacting the balance of the vessel. When Vessel 1 executed a turn (N/B), Operator 1 was thrown out of the vessel. Vessel 1 then struck the south side of Tecumseh island and swamped.