TIDE RECORDER

New Zealand Herald, Volume LXXIV, Issue 22685, 24 March 1937, Page 19

TIDE RECORDER

ELECTIiICAL DEVICE FIRST IN NEW ZEALAND INSTALLATION AT GREYMOUTH [BY TELEGRAPH —OWN CORRESPONDENT] G RKYM.OUTH, Tuesday Replacing a %stem which was both cumbersome and inaccurate, tho Greymouth Harbour Board has installed the most modern system of recording the tides, an Kvershcd electric distant tide recorder. Ihe equipment, which was imported from Kngland at a cost of approximately UJBS, is the first to be used for tide recording in New Zealand. The recorder works on tho-principle of the electric petrol gauge in motor-cars, only on a vastly bigger scale. It is operated from a float chamber installed at the lagoon dock. The movement of tho float as the tide rises and falls actuates a transmitter, which is connected to the electric-power circuit. Tho impulses from this transmitter are carried by land lino to the Harbour Board's office in Gresson Street, where they arc recorded on two big dials in the shapo of clocks, the indicator moving in a clockwise direction from zero to 16ft. The transmitter also activates a recorder in tho office, which records in the form of a graph the state of the tide througthout the 24 hours, giving a permanent record. The chart, on which the graph is automatically plotted, is kept moving at the rate «f a quarter of an inch an hour by a 30 days clock. The chart requires replacement about every four months. The Harbour Board officials, with the new equipment, which is not yet completely installed, will be ablo to tell the state of tho tide at any time of the day or night simply by consulting the dials, one of which is installed in the engineer's office, and the other in the wharf staff's room. There is no limit to the number of dials which may be connected to the transmitter, and ! thus it is possible to have any number ! of simultaneous tide readings at differ- | ent places. i The recorder will completely eliminate S tho existing cumbersome method em- | ployed by harbour officials to obtain tide readings, under which a telephone call was put in to the signalman at the Tip Head, and he in turn read the tide gauge three-quarters of a mile away by means of a telescope, and telephoned the reading to the office. Under this system, unless visibility was exceptionally good, it was impossible to determine the tide level accurately, but the human element will bo entirely eliminated by the electrical recorder.