Collision Avoidance

A freighter can be on you from the horizon in less than 10 minutes. You may be invisible from its deck – or it may not have its radar on. At night, its watch may be half asleep, or in the head. Most collisions take place at night. For large ships, generally do not try to pass ahead. Change course or speed so that it passes ahead of you.

On Enchantress we have a number of pieces of equipment to assist in collision avoidance;


  1. The person on watch does a 360 degree lookout no less frequently than every 10 minutes. Use a timer if drowsy.
  2. Know when you are in a shipping lane–mark them on the charts, and be aware that they only show at certain definitions on the electronic charts.
  3. Check the AIS/Chart Plotter regularly and adjust the definition to ensure nothing is missed.
  4. As soon as another vessel is spotted, note the time and also its compass bearing. Sight it over a stanchion or winch
  5. Check to see if the vessel shows on AIS
  6. Consider calling up the vessel on VHF if there is doubt on it's intentions
  7. Use binoculars to assess the aspect of a vessel, and at night, to identify its lights (range lights and red/green navigation lights)
  8. Turn engine on if needed to maintain or increase speed
  9. As a general rule, for the first few minutes after spotting another vessel, maintain course and speed and watch carefully to see if the vessel's bearing changes. If in doubt, or the bearing does not change, alert the Skipper and assume a collision course.
  10. If the vessel is directly ahead or on a constant bearing, contact the vessel on the VHF (channel 16 or 13) to determine its intentions, use the details from the AIS.
  11. If you do not reach it on the VHF, slow down or stop the boat to gain time. Watch carefully what happens to the bearing and the boat's aspect to find out which side you will pass on. Altering course too soon could put you closer to the vessel rather than further away. Turn on the engine. Once it is clear which side you will pass on, turn hard in that direction and pick up speed--assuming the other vessel does not change course.
  12. Action taken to avoid another vessel should be taken early and should be obvious
  13. To call on the VHF (16 or 13) use the information on AIS, if there is none say "Vessel heading (direction from compass) near (whole degrees of Lat/Long)". "This is the sailboat on your...(relative position--eg starboard bow). What are your intentions?"
  14. To get attention of another boat and the VHF doesn't work, shine a spotlight on your sails, or set off a white flare. Also, blow the air horn (repeats of 5 short blasts) or use the spotlight (repeats of 5 short flashes).
  15. At night, green to your green or red to your red is probably OK so long as they stay that way
  16. At night, If you see both red and green the other vessel is coming straight at you. Alert the skipper, and if immediately necessary turn hard to starboard.
  17. At night, red on your starboard side means you give way. Turn to starboard to pass astern of the other vessel. [In theory, if you are sailing and it is powering, it gives way but don't count on this. Better make a turn obvious and early and put your red to its red]
  18. At night, green on your port side means you should stand on and the other vessel should turn right to pass behind you. Alert the captain. It may not have its radar on, or the watch may be asleep.
  19. Remember what light combinations mean:
    • Red over white – fishing at night
    • Green over white - trawling at night
    • 2 or 3 vertical white lights - a tugboat towing another vessel < or > 600' astern.
    • If you see yellow over white, turn round. You are approaching the stern of a tugboat which is towing another vessel behind it.
    • Yellow/orange light underneath 2 range lights - submarine
    • Blue light underneath single masthead light - law enforcement vessel
  20. If, after everything, it appears that collision is unavoidable, turn head on to take the impact on the bow (the strongest point of the boat) and put the engine in reverse to reduce speed.



  1. Everyone puts on a Life Jacket and does everything possible to get clear of the other vessel.
  2. Helmsman writes down the time and GPS position on a piece of paper and puts it in his/her pocket.
  3. If Enchantress is leaking or sinking, attend to leaks and/or abandon ship
  4. Stand off the other vessel and get in radio contact (VHF 16 or 13)
  5. Get the name of the other vessel, tonnage, homeport, where bound, and last port.
  6. Write it down.
  7. Give the same information for Enchantress.
  8. Make quick assessment of damage, and trade damage reports.
  9. Offer assistance as appropriate.
  10. As soon as possible contact the Coast Guard and describe the incident.
  11. Attend to the damage.
  12. Notify the insurance company as soon as possible


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This page was last modified on: January 31, 2013

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