The wind has effect on the sailing ship, but so does the water.
One of these forces that the water has on the boat is drag. The boat must push through the water moving the water in front of it out of its way. "As the boat picks up speed, she creates waves, and these rather than the surface friction becomes the major part of the drag at higher speeds." (pg.7, Brewer) Sailing ships hull heel, an "athwartship inclination of the vessel" (pg. 208, Brewer),when they are moving faster, which increases drag on the ship. Most of the time the ship is also tipped slightly to the side instead of completely perpendicular to the water. This is due to the angle at which the boat is sailed into the wind ane the force the wind has on the ship. This difference in angle from the vertical also causes more drag on the ship.
Water has the another effect of determining the maximum speed of a ship. "When a boat which does not plane moves, it creates two waves which become further apart the faster the boat moves. At a certain speed, the distance between the wavecrests is close to the waterline length of the boat and the two crests are situated near the ends of the waterline shape of the boat." (pg. 327, Bond)