Heeling error is defined as the change of deviation occurring when the vessel heels. When the vessel changes the latitude the heeling error also changes. The electronic magnetic compass was designed to compensate for heeling error using the Poisson's coefficients. This paper shows experimental results of this electronic magnetic compass set up on board training vessel UMITAKA MARU of Tokyo University of Fisheries during her 49th voyage. The compass system consists of three axis magnetic sensor and two axis clinometer. The magnetic sensor was fixed on the compass deck and the clinometer was set up near the ship's center of gravity. Compensation of deviation was satisfactory and the residual deviation was less than 1°. When the ship changed magnetic latitude by about 20°, residual deviation was less than 3°. In the experiment, the ship was manually steered and ship's maximum rolling angle and pitching angle were about 15°and 5°respectively. Under this condition, after compensating the heeling error, this compass shows 5°difference with the gyro compass. Although this compass does not damp, software damping makes the heading value of this compass equal to the gyro compass.
