The effect of current on the course and speed of a sailing ship

Abstract

A feature of the movement of a sailing ship is that its speed depends not only on the strength of the wind, but also on the course of the ship in relation to the wind. This dependence is graphically reflected in its polar. A special feature of the movement of a sailing ship in a current is the influence of this current itself on the wind acting on the sails. The specifics of choosing the course of a sailing ship on a current, taking into account this influence, are considered. The accepted terminology is clarified and new terminology is proposed in the names of the winds involved in the creation of the apparent wind acting on the sails. The correct view of the speed triangle is shown to determine the true wind in the presence of wind drift of the vessel. A technique is proposed for determining the course and speed of a sailing ship in a current using its polar.