Needle Work

Alongside a dock hard by Britain's Royal Naval College in fogbound Dartmouth, the strangest ship in the world is being fitted out this week for a series of voyages that are to take her, within the next few years, to many an out-of-the-way corner of the seas. She is the Royal Research Ship Research, a trim 770-ton brigantine. Chief job of naval and civilian scientists, to be quartered in her midships, will be to chart magnetic variations, compare their readings with those taken by the Carnegie Institution's Carnegie before she blew up while taking on gasoline in Apia, Samoa, in 1929.

"True North" is the direction in which one points to the North Pole, but compass needles point in the direction of the magnetic pole, which is on the Boothia Peninsula in Northern Canada. Hence, only when a compass is roughly on a prolongation of the line from the geographical pole to the magnetic pole does it point true north. From other points in the world the needle, pointing to magnetic north, makes an angle with true north, and that angle mariners call variation. In the Pacific Ocean the needle points as much as 30DEG east of the geographical pole; in parts of the Atlantic and Indian Oceans as much as 45DEG west.

What has plagued navigators is that variation is not only different for different localities, but that from year to year the variation varies because the magnetic pole moves. No one knows why and no one knows precisely how much. Scientists do know that since famed Astronomer Edmund Halley first made his chart of variations, A.D. 1700, the variation in England has changed by more than 37DEG. Seaman-scientists of the Research are not sure they will discover the reason for the annual changes. But they will determine the amount of change by comparing their readings with those taken by the Carnegie more than ten years ago.

Mariners who correct their compasses for variation also have to correct them for deviation, a local error caused by magnetic metals (chiefly iron, steel) in their own craft. The Research is unique because she is nonmagnetic in every possible detail, will have infinitesimal local deviation errors. A throwback to the wooden-ship days, she has a hull of teak, bolts, girders and anchor chain of aluminum bronze. Her cooking utensils and tableware are aluminum; her four Diesels (three for auxiliary power, one for propulsion in calms) are of bronze and aluminum. Her only steel is in their crankshafts and cylinders and it is nonmagnetic. Before she shoves off on her voyages, the clothing of her crew will be carefully searched for metal buttons, nailed shoes which might throw off her compasses by a hair. Big problem for the crew: where to get razors which will shave whiskers, will not shave the accuracy of compass readings.

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