When you are approaching a sailboat, you should allow the sailboat the right of way. The only exception is when the non-powered vessel is overtaking you. Otherwise, the powerboat should always give the right of way to the sailboats. If you change your course and seed when the sailboat is approaching or overtaking, you risk causing an accident. You should only change speed if you are on a collision course with the craft. That is when you can go against the navigation rules.