: I say it is the volume of water you displace as the hull moves
: through the water. But we are talking molecules here so lets not
: hurt our heads. It is the reduction in friction that is
: significant.

Perhaps.. moving a greater mass takes effort, if the reduction in friction is less than that required to move that extra mass then the net effect is a loss of speed, not a gain.

What works on a 500 lb. sailboat with 500 lbs. of crew weight may well not transfer directly to a 30 lb. boat with a 150 lb. paddler.

Bill H.