How to Plan an Ocean Passage


  1. Find the cruising speed fuel consumption of your vessel (and daily water usage)
  2. Calculate the bunker capacity of your vessel and determine the days/distance between bunker ports. You now have the range to which 3 days or 20% should be subtracted as a safety margin.
  3. Find the port of destination, from Ocean Passages of the World (NP136) and determine the departure and arrival waypoint for the ocean leg.
  4. Measure the distance from berth to waypoint and add to ocean leg distance.
  5. Determine if you can do the passage
  6. Consider intermediate bunker port.


  1. Identify the ocean passage on a gnomonic chart and take off the latitude for each 10o of longitude. These will be general waypoints. (These can also be obtained from ECDIS GPS)
  2. Plot waypoints across the ocean on the relevant monthly routeing chart eg NP5124(1) for North Atlantic in January. Your route may be on the body of the chart as a green line with distances between waypoints from ocean passages of the world given and named e.g., ‘Halifax 2934 Bishop Rock’
  3. Ascertain the loadline zone shown on the chart. Does this limit the amount of bunkers you can load? (Not if you have an all seasons loadline)
  4. Observe Iceberg areas ^^^^^, or pack ice areas [ , and plan to avoid these where practicable.
  5. Now ascertain the average wind strength on your passage for that month. Compare the wind strength with the ‘Ships Performance Curves’ which you may have got from either the architect or an external weather routeing agency.
  6. Obtain ocean current information and tidal stream information for your passage.
  7. What is the likelihood of TRS at that time and can they be avoided by general routeing.
  8. Using the above recalculate the time on passage and fuel consumption.
  9. Determine how positions will be obtained for each part of the passage and what MSI will be available to you.
  10. What port of refuge is available and what is the available SAR facility.
  11. Consider shore based ocean routeing support. This costs approximately £400 for an ocean passage and can save money on fuel and damage reduction.


  1. Ensure that the planned passage is agreed by the bridge team and that expected weather conditions are known. Refer to NP100 Mariners Handbook for Ice, Cloud, Sea State.
  2. Liaise with ocean routeing company every 12hours with current position and your own weather observations. Prepare mandatory reports where appropriate as per Solas V Reg 31.


  1. Confirm weather forecast against your own observations and highlight any differences.
  2. Observe for signs of TRS, frontal depression, unexpected current.
  3. Check that vessels progress is as expected and keep DPA informed of progress.