Marine compasses are usually mounted in a protective housing like a wood box or a wood or brass dome called a binnacle. The first reference to gimbals on compasses for marine navigation was in 1537. The azimuth compass is a large marine compass used at sea to sight on the sun at sunup or at noon in order to determine magnetic deviation from true north. This application requires knowing the date and latitude, enabling the crew to calibrate the ship’s navigational compass to true north. The card of a mariner’s compass has 32 divisions called rhumb-lines instead of 360 degrees. Rhumb lines simplify navigational headings and tracking especially in high winds and rough waves.