磁気コンパスの傾船差と傾斜角度との関係について(日本航海学会第18回講演会)  [in Japanese] The Relation between the Heeling Error of Magnetic Compass and the Heeling Angle  [in Japanese]

The principal heeling errors are due to the induction by earth's field in soft iron rod e and k and to the vertical component of permanent magnetism in the ship R, where e is the athwartship component of soft iron passing through the compass and k the for and aft component. By the Poisson's equation, the heeling errors due to e and k vary as sin2i when the ship is heeled through an angle i, but that due to R varies as sini. By the schematic experiment, we confirmed that the above relation is hold. Usually the heeling error is represented to vary as i. So when i increases, the heeling errors are not accurately represented by the latter expression. We discussed about the errors by the latter expression, and find that if the heeling errors are precisely measured the perfect correction of the heeling error is possible.