: I was considering adding graphite powder to the resin on the hull of a
: schooner am building. It seems, graphite makes the hull slide against
: other things. It will not help you go through the water better...
: according to those I have talked to.

It does seem reasonable, but I don't think it is neccessarily true. Graphite is a good lubricant because the graphic molecules slide easily against each other. In order for this to work in water, the water would have to be stripping off the outer layer of the boat as you paddle so that the water is lubricated by a layer of graphite moving against the layer still attached to the boat. Hopefully your boat will not be losing much material do to moving through the water.

: It is good where parts need to slide: like center board trunks

In this case the centerboard would probably covered with graphite as well so the board and the trunk can easily move against each other.