ISSN 0711 -5628 Edition No. 28, November, 1983 You need the best imaging Side-Scan is well known, but sonar available. This is it - the the 971 's high definition colour 971 . A colour imaging, multi­ display adds a completely new purpose miniature sonar. Best dimension. Surfaces are recog­ because it displays the widest nized by their signal strength, as range of signal levels. Because shown by their colour. And targets each of its 128 distinct colours which you miss with a regular so­ represents a precise sound level. nar's limited on-screen range show Because it has the highest defini­ clearly on the 971. tion - X million pixels- to show This much performance would the finest details. And because normally require a rack full of the colours and high definition equipment. Not so with the 971. produce breathtaking images. Perspective Mode: For Pilotage The on-board processor is com- spective Mode for Pilotage and a sound image of the outside world is presented with stunning realism. You 'fly' into the scene guided by the perspective grid. Switch to the Polar Scan Mode for General Surveillance. If a job calls for monitoring and control­ ling traffic at an oil rig, this mode will guide divers and vehicles dir­ ectly to a rendezvous or work sta­ tion. Constant monitoring can be achieved with an NTSC or PAL converter and a standard video recorder. And playback utility is enhanced by the on-screen data, Sector Mode: For Obstacle Avoidance which lets you record date, time, Side Scan Mode: For Large Area Surveys . depth ... As shown here, the colours re­ pact, the Sonar Head is small and present about one tenth of the Polar Mode: For General Surveillance . yet light enough to fit any ROV. actual brilliance of the monitor Or to pass through drill strings, screen. The sonar also displays a casings and sea chests. dynamic sequence of images, en­ Performance, versatility, size, hancing your interpretation. value. Now you know. With the 971, you can 'see' as No other sonar comes close. far as 100 metres. Compare that to a few metres with your eye or TV. Add the feature of five opera­ ting modes/ display formats and you have an unrivalled versatility. For instance, the narrow sonar beam of the Sector Scan will de­ SYSTEMS LTD tect even the smallest hazards and 2830 Huntington Place the display will reveal them. Per­ Port Coquitlam, B.C., Canada V3C 4T3 fectly. Switch to the unique Per- Tel (604) 464-8144 Telex 04-353637 EDITION NO. 28 LIGHTHOUSE NOVEMBER, 1983 JOURNAL OF THE CANADIAN HYDROGRAPHERS' ASSOCIATION National President . A.D. O'Connor Secretary-Treasurer . R. Chapeskie Vice-President, Atlantic Branch ..... ... .. .. ... ........ R. Mehlman Vice-President, Ottawa Branch ............ .... ... .... .... J. Bruce Vice-President, Central Branch . • . B. Richards Vice-President, Pacific Branch . D. Popejoy Vice-President, Quebec Branch . P. Bellemare Editorial Staff Contents Page Editor . A.J. Kerr Assistant Editors ... ........ .. ...... ... .. ... R.M. Eaton R. W. Sandilands Editorial ............ .......... .. ......... ... .... Social News Editor . C. M. Schipilow Message from the President Industrial News Editor . J . Goodyear Advertising Manager .... .... ....... .... ... J.G. Stead Bubble Memory . 4 Graphics . ...... ... .... .. ... ....... .. .... J.G. Stead Gavin McLintock and George Macdonald Financial Manager .. .. ....... ......... .... R.C. Lewis Dolphin: On Trail . 9 K. Malone LIGHTHOUSE is published twice yearly by the Canadian Contours & Contouring in Hydrography . 10 Hydrographers' Association and is distributed free to its members. D. Monahan and M. J. Casey Yearly subscription rates for non members who reside in Canada Airborne GPS Trials ................................ 19 are $10. For all others $ 15, payable by cheque or money order to M. J. Casey, N. Beck, R. J. MacDougall and R. A. O'Neil the Canadian Hydrographers Association. Annual Report ........ .. ................ ....... 22 All correspondence should be sent to the editor of LIGHT­ A. D. O'Connor HOUSE, c/o Canadian Hydrographers' Association, P.O. Box Loran-e Calibration of Large ..... .. ... .. .... .... ...... ... 23 1006, Dartmouth, Nova Scotia, B2Y 4A2. Scale Charts M. J . Gourley and J. Turpin The Microfix 100C ............. .. : . 26 P.R. Milner New Bathymetry for the . 35 LIGHTHOUSE Queen Elizabeth Islands Advertising Rates Per Issue John Warren Oh Say can you see? . 36 Outside Back Cover ....... ... ... ......... $ 180.00 CAN. John Cookson Inside Cover, Page ........... ....... .. ........ $170.00 Half Page ...... ..... .... .... .. ..... ... $115.00 Recovering Datum Reference . 39 Richard Palmer Body, Full Page ........ ... .. .. ..... .. ....... $155.00 Reminiscences of a Retired Hydrographer . .... ..... 41 Half Page . .. .. .. .. $100.00 N.S. Gray Quarter Page ......... .. .. ... .. .. .. ... $80.00 Gazetteer of Undersea Feature Names 1983 ........ ... .. ... 47 Department of Fisheries and Oceans Professional Card ... ..... .. ..... .. ... ..... $45.00 Single-Page Insert . .......... ... ...... ... .. $ 155.00 Using The Digial Data Base . • . 49 to See Between the Lines Color rates available on request Peter Kielland All Rates Net To Publisher Errata . 55 The Canadian Hydrographic Service (Atlantic) Sweep Program Closing Dates: April Issue - I March CHA!CHS News .. ....................................... 56 November Issue- I October News from Industry ... .... .. ... .. .. .. ...... 60 For a rate card and mechanical specificarions conracr: Editor, LIGHTHOUSE Canadian Hydrographers' Association P.O. Box 1006 VieH'S expressed in articles appearing in rhis publication Dartmouth, Nova Scotia are those o{ rhe aurhors and not necessarily rhose of rhe B2Y 4A2 Phone (902) 426-3497 Association. 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Members, professional bodies and societies; from over fifty countries, represent engineering consultants; post and all areas of hydrography, ocean­ telecommunications organisations; ography, geophysics and civil acoustic and electromagnetic engineering at all levels of instrumentation manufacturers; expertise. Organisations repres­ oceanographic and land survey ented include contract survey instrument manufacturers; companies; port authorities; dredging and salvage contract- government, military and ors, and surveyors in all fields of private practice. The~................. __ __. ....... Hydrographic Society SERVICES The Hydrographic Journal MEMBERSHIP Information Bulletin Individual: International Symposia £2 joining fee + £18 p.a. * General & Regional Meetings Students & Retired Members £12 p.a. * Technical Workshops Corporate: £20 joining fee + £80 p.a. * Exhibitions Branch Corporate: Special Publications no joining fee £40 p.a. * Employment Advice •or equivalent in US$ or Guilders where applicable. THE HYDROGRAPHIC SOCIETY NORTH EAST LONDON POLYTECHNIC FOREST ROAD LONDON E17 4JB ENGLAND Telephone: 01-590 7722 Netherlands National Branch USA National Branch Rijkswaterstaat, directie Noordzee NOAA/NOS (OA/C 35 x 3) Koopmansstraat 1, 2280 HV Rijkswijk 6001 Executive Boulevard, Rockville Postbus 5807 Tel: 070-94-9500 Maryland 20852 Tel: (301) 443-8232 EDITORIAL The question so often asked in these days of tight financial res­ repetitious surveying and charting. And so, there is perhaps no traint is "When will the charting be completed?" To this I use three end to the task of the hydrographer whether he be in government replies. One, hydrography is not like land surveying. Hydro­ or industry and on that note we may all wish to rest contented. But, graphers cannot photographically see all the area they must mea­ if we compare hydrography with other ocean sciences, it must be sure. "Air photography" of the seafloor in the form of acoustic considered to have reached middle age and some of the thrill has imagery is still very crude, and