RedactedNarrative: O1 had just unloaded V1 at the dock at Waldo Lake Access Area on Lake Traverse. O1 proceeded to travel away from the dock and increase speed.  As O1 increased speed of V1, the transom of V1 sank downward into the water from the thrust of the propeller. The skeg and propeller of V1 struck a submerged object which broke the skeg, bent the propeller shaft and 2 blades on the propeller.  O1 was the only occupant on board and was not wearing a PFD.