Passage Planning

Passage Planning

Planning a passage can be a daunting for many people. What information do you require, how much detail do you need?  This worksheet aims to help those planning to complete their RYA Day Skipper or for RYA Day Skipper’s who are looking for a way to refresh their passage planning skills.

For a lot of people the first time they plan a passage is during their RYA Day Skipper course.  Largely your instructor will have worked out that the passage is possible and suitable for your crew and boat.  When you come to plan a passage on your own you will have to decide where to go and if it is suitable given the wind, tide, crew and boat.  This is often the hardest part and once a decision has been made then you can start planning your passage.  A weekend of day sailing in the Solent can often be more difficult than a coastal passage along the South Coast, or cross-Channel.

How Far?
This is one of the most important questions that you need to answer.  How long would you like to spend sailing?  You will need to know the average cruising speed of your boat; most boats can sail between 5-6 knots per hour but if it is a smaller boat, the cruising speed may be less.  If you are sailing with an experienced crew used to longer passages, then a 6-8 hour sail should be suitable.  If you are sailing with an inexperienced or young crew then you may only want to consider a 3-4 hour sail.
If you have a clear destination in mind then you will need to know how far it is from your starting point, this will tell you how long the passage should take.

Weather Forecast
What is the weather forecast and is it suitable for the boat and crew to manage during the passage?  What is the forecast for the return trip, if applicable?  The direction of the wind is very important, if you have to sail into the wind then you may wish to add 1/3 of the total distance to allow for the extra distance you will need to sail- it may also be a more uncomfortable passage. Consider reefing in harbour before you leave and ensuring you have plenty of snacks and drinks to hand. If the wind is directly behind the boat, then it will be a more comfortable sail, but boat speed will be reduced if the winds are light.  Could the crew handle flying a downwind sail like a spinnaker or cruising chute?  What if the weather changes?  Do you have enough fuel to motor if the wind dies and have you considered alternative closer ports as a safe haven if you encounter a problem? Is your safe haven accessible at all states of tide?

Constraints
If you sail in a non-tidal area then you don’t need to worry about tides, but if you sail in a tidal area then you will need to take the tidal streams and heights into consideration.  Are there any tidal restriction leaving your home berth? If so then you will have to work out when you can leave.  This will give you a departure time. If there are any tidal restrictions at your home berth you will need to know the tidal heights. If there are no tidal restrictions then you may not need to know the tidal heights.  Are there any tidal restrictions at the destination?  If so then you will need to work out when you can arrive.  This will give you an arrival time which in turn will allow you to work out a departure time.  You will need the tidal heights for the destination.  A positive tide will increase your cruising speed; a negative tide will decrease your cruising speed.  Consider the wind direction in relation to the tide; wind with tide will give a smoother passage than wind against tide.

Departure Time
You may have a departure time based on a tidal height restriction, but often you will want to plan your departure to take advantage of the tidal streams.  Work out when the tides are in your favour, consider how long it will take to leave you berth.  When the tide is turning the flow is generally at its weakest so consider leaving before the tide turns if you are making a longer passage.  Sailing against a weak tide for the first hour will allow you to take advantage of the full tide.  Or sail in the shallows where there is often a back eddy before the tide turns.

Navigation
You will need to prepare a pilotage plan for your departure and your destination, if there is a possibility of a night departure or entry ensure you include lights.  Look at the pilotage for any alternative ports you have considered- if you are experiencing a problem the last thing you will want to do is work out how to enter the port.  It is useful to know the height of tide for your alternative port as this will give you a minimum depth of water that you can sail in.

While planning your passage ensure you note any hazards en route, take care of tidal races and plan your passage to avoid them.  Watch out for common errors. A classic mistake is to plan a longer passage than necessary. Mark up your waypoints and remember that a waypoint doesn’t have to be on a buoy. Make sure you know the distance and bearing between your waypoints as this will allow you to double check that you have entered them into the GPS correctly.  Knowing the tidal height during the passage will make decisions easier, consider listing the depth of tide hour by hour, this way you will know how close to shore you can sail at all times.

Good passage planning will make your passage more enjoyable. The more information you have to hand while planning your passage will make your decisions easier while on passage.

Remember not to leave everything to the last minute so you can enjoy the passage.

 Passage plan to-do list:

  • Check how far your destination is
  • Check the weather forecast to see if it is suitable for your passage and crew
  • Check for tidal constraints, this will give you a departure time
  • Plan to make best use of any tidal streams
  • Check for hazards on route, plan to avoid them
  • Consider ports of refuge in case the weather changes if you have a problem
  • Plan your port entry and exit
  • List bearings and distance to waypoints to ensure you don’t make a mistake when entering them into your GPS.

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