1 / 24

Lesson 15: Voyage Planning and Time

Lesson 15: Voyage Planning and Time. Lesson 15: Voyage Planning and Time. AGENDA: ETA/ETD Determining Zone Time Date-time Group (DTG) Format The Voyage Planning Process Optimum Track Ship Routing (OTSR) Applicable reading: Hobbs pg. 252-274. Terms and Definitions.

kittredge
Download Presentation

Lesson 15: Voyage Planning and Time

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lesson 15: Voyage Planning and Time

  2. Lesson 15: Voyage Planning and Time • AGENDA: • ETA/ETD • Determining Zone Time • Date-time Group (DTG) Format • The Voyage Planning Process • Optimum Track Ship Routing (OTSR) • Applicable reading: Hobbs pg. 252-274.

  3. Terms and Definitions • Estimated Time of Arrival (ETA): the time and date of arrival that must be achieved. Usually specified by higher authority. • Estimated Time of Departure (ETD): a computed estimate of the time and date of departure that will allow the ship to arrive on time.

  4. Terms and Definitions Speed of Advance (SOA) – The speed intended to be made good along the track. • The average speed in knots which must be maintained during a passage to arrive at a destination at an appointed time.

  5. Terms and Definitions PIM- • Planned track movement based on required SOA • USS Indianapolis • Indicated every 4 hours • Needed for ALL Voyage Plans • PIM symbol must be different from standard navigation symbols. Ex: 1200Z PIM

  6. The Mean Sun & Zone Time • The mean sun completes one circuit around the earth every 24 hours, or 15 degrees of longitude each hour. • Each 15 degrees of arc is a time zone. • Within each zone, time is reckoned according to the position of the mean sun in relation to the central meridian of the zone.

  7. Greenwich Mean Time (GMT) • Centered on prime meridian. • Extends 7.5o east and west of the prime meridian. • Referred to as “zulu” time, because the time zone is designated by “Z.” • Each additional time zone (as we move east or west) has a boundary every 15 degrees past 7.5o.

  8. The International Date Line • The 24th time zone is split in half, with each zone on either side of the 180th meridian being only 7.5o wide.

  9. Determining the Time Zone • To determine the time zone, simply divide the longitude of a location by 15. • If the remainder is < 7 1/2°, quotient is the zone • If the remainder is > 7 1/2°, shift to the next zone • For eastern longitudes, place a negative sign (-) in front of the number; for western longitudes, place a positive sign (+) in front of the number.

  10. Time Zone Example • The longitude of Norfolk, Virginia is 076o 18.0’ W. What time zone is this? • Answer: • 076° 18.0/15 = 5 w/remainder of 1°18’ • 1°18’ < 7°30’  Zone description = 5 • Since longitude is west, time zone is +5. • The time zone indicator letter for this zone is R, so the zone is completely described as +5R

  11. Daylight Savings Time • As an example, when Norfolk observes daylight savings time, it keeps +4Q instead of +5R time. • The time kept at any particular location and time of the year can be determined from either Coast Pilots or Sailing Directions.

  12. Time Conversions • During voyage planning, all times are normally expressed in Zulu (GMT) to avoid confusion. • As necessary, times are converted to the local time zone for ease of use. • The formula for all conversions is: Zone time + zone description = GMT

  13. Time Conversion Example • It’s 0800 (local zone time) in Naples, Italy. What is this time, expressed as GMT? • Answer: • Longitude of Naples is 014o 16’ E, so the time zone is -1A. • GMT= ZT + ZD = 0800 - 1 hour = 0700 Z

  14. Date Time Group (DTG) • Official Navy format for expressing time and date. Also in all naval message traffic. • An example: 171000RJUN89 translates to: 17 1000 R JUN 89 DAY 4-DIGIT TIME 3 LETTER LAST TWO OF TIME ZONE MONTH DIGITS OF YEAR MONTH INDICATOR

  15. Shipboard Time • During a transit, the ship’s clocks are set to the time zone in which the ship is located. • As the ship transits eastward, clocks are periodically advanced 1 hour to conform to the proper time zone, and vice versa for westward travel.

  16. Rhumbline Track on Mercator Chart • Rhumbline Sailing: • Appears As a More Direct Route on Mercator Projection • Maintains Constant True Direction and the Same Angle at All Longitude Meridians • For Short Distance Tracks: • Rhumbline Is Same As GC Track

  17. Track Development • Steps: • Select Great Circle and Mercator Charts • Depart and Destination Positions Plotted • Start at First 5° Long Meridian & Retrieve Latitude and Longitude every 5° Meridian thereafter  • Transfer Track Positions to Mercator Projection • Record Positions on PIM Sheet  

  18. The Voyage Planning Process • Obtain and update charts and pubs • Determine time of arrival and departure. • Plot the intended track • Plot a great circle on a gnomonic projection • Transfer rhumb lines to a mercator projection • Construct a track summary listing courses, distances, and times for each leg.

  19. Optimum Track Ship Routing (OTSR) OTSR Provides: • Preliminary planning • Route Recommendations • Route Surveillance • Divert Recommendations

  20. REVIEW • What is SOA? • What is OTSR? • ZULU time is also known as _______? • What time zone is Voyage Planning completed in?

More Related