磁気コンパスボウルの動揺に伴うカードの動きについて

抄録

There are some causes of indication error on magnetic compasses when the ship rolls or pitches. These are considered which comes from so called heeling errors and the error caused by the direction of gimbal axis. However, observing the movement of a magnetic compass card in a small boat while sailing, we found that the card are deflected by the swing of the bowl. And it is obviously increased with the rolling and pitching. We simulated the bowl motion as that of which is brought like the real rolling and pitching, and the drifted angle was measured. An example is as follows. A drifted angle of 3.6° of the compass card was obtained in the case that an inclination of the up and down line of the bowl is 10° from the vertical line, and the axis of the direction turns around the vertical line through the compass pivot in a speed of one turn per 15 seconds where the horizontal magnetic flux density is 18μT.