The resistance offered by a ship to movement
through water may be resolved into two principal
components: frictional resistance and residual
resistance. The frictional resistance arises from
frictional forces set up by the flow of water along
the surface of the hull, and is consequently influenced
by fouling and the coatings of paint used
for its prevention. The residual resistance is due
to pressures developed in pushing the water aside,
and arises from the form of the hull.