The underhanded throwing theory has been derived from the rotation of large rocks that have been observed, a forward rolling motion like a bowling ball was noted by some eyewitnesses. That would not rule out an alternative overhanded toss, but chimps have a similar underhanded way of throwing...it is certainly something of interest. Stories of basketball sized rocks arcing only slightly indicate a powerful force to be able to launch such weight on such a trajectory, generally the rocks are not that large and demonstrate a preciseness defying chance. Occasionally an individual is struck and injured by such an object, generally considered to be a miss throw. So as with the greatest pitchers in MLB, while trying to force you off the plate they can just plain throw a wild one and hit you. My advice under such circumstances is to go back in the dugout till the game is over, but if your man enough lean out over the plate and take one on the shoulder...though taking first base will not be an option here...also not a great idea to try going out to the mound for a take down...just saying...
When I was in my 20s I made numerous fishing trips to Ontario's Lake of the Woods, we would be darting through the maze of islands in search of trophy Muskie, which we did catch exceeding 40 pounds! I know what a beaver tail sounds like slapping the water vs a large rock kerr-plunging. The large rock displaces water much like a splash dive, the result is a two toned kaa spush. I have memories of such splashes near us at certain times, the guide had hinted about bigfoot at other times, I wonder if his travels brought him into contact from time to time. He loved to fish a dusk into the night, and took us as well. We saw black bear exploring islands, so I am guessing the Squatch in that area do the same. We were also dropped off at some portage lakes, and I seem to remember an odd splash there as well. Funny thing is how you write such things off in your mind, but you know it was not a normal sounding beaver slap, and there was no beaver in the area. This was the central part of LOW, very suitable habitat....I would say perfect....