1. CELESTIAL NAVIGATION Section 22 Day’s Work at Sea Prepared by: John C. Hudson Saanich Peninsula Squadron, VISD Jan 2006 / Rev. Jan 2007

2. Day’s Work at Sea - uses most of navigational procedures learnt in this course - real world weather conditions often preclude sights being taken at normal times - regardless, navigator must maintain DR course at all times and EP’s when prudent

3. Responsibility of a Navigator - navigator required to know vessel’s position as accurately as possible at all times to ensure safety of vessel, passengers, crew and cargo - no universally accepted standards of navigation at sea; each navigator must develop a daily procedure

4. Responsibility of a Navigator daily procedure will depend on: - particular vessel - its location - prevailing weather - navigational equipment avail. - orders from captain/owner

5. Responsibility of a Navigator - recommended that navigator takes daily dawn and twilight star FIX as well as noon RFIX - supplement during day by sun and/ or moon sights as needed - if so equipped, navigator should obtain ship’s position by electronic means

6. Responsibility of a Navigator - for twilight FIXes, 3 body fix is desirable - run of 3 observations on each of 3 bodies, averaging times and “hs” is good practice to improve accuracy and eliminate bad sights - advanced planning and pre- calculation of expected positions is sign of efficient navigator

7. Navigator’s Notebook and Log - navigator expected to record and retain all data to substantiate plotted positions recorded in log and on chart - these records should be readily available for submission to authorities in event of an enquiry

8. Navigator’s Notebook and Log - no specified method of maintaining such data; record may be simply in form of continuous chronological account of: - navigational procedures followed - calculations made - positions determined

9. Navigator’s Notebook and Log another format may use separate records for: - course, speed, times and positions of course changes and celestial observations - log of position co-ordinates together with method of determination

10. Navigator’s Notebook and Log - example of deck log used in CPS courses See figure 16.12 on page 137 - deck log should contain complete account of voyage and is important reference document

11. Data to be submitted to Class Instructor - successful completion of Day’s Work at Sea is pre-requisite of CN course - class instructor must certify that this requirement has been completed - submission to include Plotting Sheet, Sight Reduction sheets, Work sheets showing all calculations and Deck Log

12. Data to be submitted to Class Instructor - all work should be arranged in chronological order - for Deck Log, use blank DL01 forms - remarks column should contain concise information relevant to navigational work (see Fig 16.12, page 137)

13. Data to be submitted to Class Instructor - courses, lines of position, FIXes, etc. should be plotted and labelled according to CPS standards as shown in section 16 - do not obscure lines with labels or other recordings - submit calculations separately on work sheets

14. Numerical Tolerances - report zone time to nearest minute - watch time to nearest second - position to nearest 0.1 minute - azimuth to nearest 0.1 degree - set of current to nearest degree - drift of current to nearest 0.1 knot - Great Circle distance to nearest mile

15. Accuracy Required - answers are given for “Sienne Cruise” on page 172 so work may be checked by student as it progresses - exact duplication of co-ordinate in plotted positions is not expected, but if exceeds 0.1’ in L or Lo, calculation and plot should be checked

16. Time of Completion of the Day’s Work at Sea - this exercise should be started as soon as relevant sections are covered in class - “Sienne Cruise” is very similar to Open Book portion of CN Course Examination, so important to fully understand and complete correctly - read section 22.6.1 carefully!

17. BEST WISHES for the SIENNE CRUISE and the EXAM The End