Aug-Sep-Oct, Nov-Dec 1971-Jan 1972 - Navy League of Australia

MrrCHELLU«MYp i v a l cereals with great flavourcanmake'emPace Four THE NAVY November-December-January, 1971/72HYDROGRAPHtRSCOURSE— the survey officers who areexpected to carry out oceanographictasks with little or nosupervision, and the surveyrecorders who initially assist theofficers and later, as seniorrecorders. shoulder moreresponsibility.The term oceanography covers amultitude of fields connected withthe ocean including its physicaldimensions and properties, itschemical composition, biology,meteorology and geologicalproperties.The detailed study of all thesesections, many of them scientificallynew. is beyond the scope of oneman. But the officer's course in 5months endeavours to cover asmany of these subjects as possibleso that students can select somefacet to study further.Additionally, as the HydrographicService of the R.A.N, is the primarycharting authority for the waters ofAustralia. New Guinea and southernareas of the Pacific Ocean, emphasisis placed on the teaching of hydrographicsurveying at the school.The final product of the hydrographicsurvey is the published chartwhich goes on sale to internationalship owners and to a public withinterests such as yachting, fishing,skin diving or quiet Sunday boating.The hydrographic surveyor mustbe capable of producing a contouredpicture of the sea bed. delineatingthe coast line, accurately fixing theposition of submerged rocks andreefs — especially those dangerousto navigation. He must recogniseand chart all topographic featureswhich may help a mariner determinehis position.He must also understand tidaltheory and be able to analyse andpredict heights, and the times ofhigh and low waters.He must record tidal stream andocean currents. The survey must beaccurately located on the earth'ssurface and the true meridian (northpoint) determined by astronomicalobservations of extreme precision.While a chart probably exists of anarea, it could be based on a surveyundertaken more than 100 years agoby surveyors undersail using aweight on a marked line todetermine the depth.For all their painstaking care andlong hours of work, surveyors ofbygone days could not survey aseffectively or as accurately as is nowpossible with electronic echosounders, radio fixing systems andmechanical propulsion.The survey recorder has beendefined as a man among men and asailor among sailors. He is expectedto work long hours in the field oftenunder difficult and trying conditions.He may be a member of asounding boat's crew detached fromthe parent ship for extended periods,or based in a shore camp on aremote coral island operatingmodern electronic position-fixingequipment so that the survey ship— possibly 200 miles away — canaccurately and continuouslydetermine her position.To "The Navy",SUBSCRIPTION FORMBox C178, Clarence Street Post Olflce,Sydney. N.S.W., 2M0. AustraliaAlternatively, heof that ship's sur ey telin the collection o informsto advance scienti c knowlj^j^This could laU a i H j "observations, the measurement otthe intensity of the earth's magneticfield, characteristics of sea water atvarious depths, cores and dredgesamples of the bottom of the sea andplankton hauls.It is the business of the HydrographicSchool to ensure that themen conducting these tasks do sowith the professionalism expectedby other world oceanographicauthorities.It may be said that the marinerplaces boundless confidence in thepublished chart and almostinvariably assumes that, where nodangers are shown, none in factexist.It is the surveyor's business to seethat this trust is not misplaced.I eadoie SI JO being '