Heavier than I thought!
The last time I was in Vancouver, the fellow sitting next to me at the marina pub was a logger. This subject came up and we did the calculations for an average length, average diameter, almost saturated log. I don't remember the figures, but I remember it was far heavier than I had ever imagined. If the prop turns without any new vibrations and the rudder turns freely and the bilge pump is not running extra cycles you survived. The up side is that at four knots you did not put as much energy into the battering ram as you would have at 6 knots. I know in a situation like this everything becomes a little surreal as you wait for the next impact, but how solid did it sound/feel?