|The article describing the magnetic condition of the steel dragger Cap’n Bill III* is of the very greatest value to anyone who is interested in the magnetic compass and its use. The figures obtained show clearly how the magnetism of the vessel changed during the first few weeks of service and then settled down. An early change of this nature is sometimes so marked that, where the swinging ground is immediately adjacent to the building yard, 1 have sometimes found it nrrcssary to turn the ship about for a while with the engines running at high speed and with full helm before it has been possible to start adjusting at all. Although, as in the case of the Cap’n Bill III, the magnetic field may stabilise itself in the roursc of a few weeks, where the compass position is badly designed magnetically, tranquility of this field may be upset again at a later date by some untoward occurrence. There is a classic case of a British vessel with an all-steel wheelhouse which cnrountered exceptionally heavy seas and the blow from one particularly large wave so demagnetiscd the forward side of the structure that thr deviation of the compass was increased by nearly 30° in a flash and as a result the ship was very nearly lost.
|NAVIGATION: Journal of the Institute of Navigation, Volume 7, Number 1
|70 - 74
|Cite this article:
|-,, "NOTES AND COMMENT", NAVIGATION: Journal of The Institute of Navigation, Vol. 7, No. 1, Spring 1960, pp. 70-74.
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