Chartwork and Fixing295.unknown A bold thick line. Course: Along the track. DR (Dead Reckoning): Allowing for direction steered at speed through the water only and for NO OTHER factors. Tidal Stream: Three arrow heads from a tidal diamond, show rate and effective time. Wind: allowing for wind, tidal stream, current etc. 1.2 B 060900 06 Darkness Change of Chart Visual bearing transferred be highlighted Clearing Bearings - Solid arrow Wheel over bearings (2) - show position and est time with open arrow head, show wheel if not standard Compass or Gyro bearing (3 or more) Transit (must be sensitive) Gruntproductions 2009 Gruntproductions 2009 Soundings Always use the largest scale chart appropriate to the purpose: Corrected first. More detail. Gruntproductions 2009 USING CHARTS Transfer position by range and bearing and Lat and Long. Check unit of depth. Only one chart on the table at any one time. Use soft pencil - Don’t dig. Don’t doodle !!!! Transfer position by range and bearing and Lat and Long. Note down position in Nav Record Book. Plot onto new chart. Gruntproductions 2009 The Fix Visual Fix : Radar Fix: 0926 0957 FIXING Cross cut of 2 position lines. 3 position lines are used as error check. Use Visual / radar conspicuous points. Are points charted ? Aim for a good angle of cut. Aim to fix at least every 6 minutes. Gruntproductions 2009 Freedom from Gyro repeats. Disadvantages Manpower intensive. Gruntproductions 2009 Possible Positions q° q° q° f° f° f° Duration of fix Reading Error: Compass Error: Gruntproductions 2009 Reduction of a cocked hat using Station Pointer. Gruntproductions 2009 Running Fix Elevation of charted objects given above the Datum of MHWS. Value of MHWS either given or obtained from Tidal Level Table on chart. Height of tide usually given. Beware of index error if given. Gruntproductions 2009 Nories Tables Distance by Vertical Angle (page 478) Calculator can be used if desired. Tan VSA = h/d where h is height of object and d is distance from object. Gruntproductions 2009 M97/1295-9-13 Take 3 bearings and shoot up a further mark Time fix to coincide with DR/EP Take bearings quickly (remember last 2 digits) Bow/Quarter first, beam last Charted and visible! Are they circular? 1000 1015 1030 190 8 8 Gruntproductions 2009 Fix 0900 30 Course and Speed Made Good Tidal Stream Vector Speed Made Good Course to Steer Tidal Stream Vector Course to Steer Speed Made Good This is a vector (relative velocity) triangle which can be constructed in any convenient position such as the Compass Rose Gruntproductions 2009 27 1415 1427 27 1415 1427 31 1410 1500 15 Direction (Course) and Distance to be steamed in the next 45 minutes Gruntproductions 2009 Gruntproductions 2009 Gruntproductions 2009 Any Questions?
