ブロック式建造漁船の自差の変動について-I(日本航海学会第32回講演会)

抄録

A deviation of magnetic compass of the ships which were built by the block system varies by the change of ships sub-permanent magnetism for a short period. Measurements on this deviation of Oshoro-Maru were made about two years after she was built. As the retult of analyzing B by P & c, and C by Q & f, the resultant values of P and Q at Hakodate are as follows ; The effect of the sub-permanent magnetism at the compass after her building, showed an unsteady value for a period of about two years. (Fig.3) The F showed an unsteady direction. (Fig.3) where: P: Fore and aft component of the force at the compass due to permanent magnetism c: Constant relating to vertical soft iron in the fore and aft line Q: Athwartship component of the force at the compass due to permanent magnetism f: Constant relating to vertical soft iron in the athwartship line F: √<P^2+Q^2>