Collision and Collision Avoidance

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          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.


  1. The person on watch does a 360 degree lookout no less frequently than every 8 minutes. Use a timer if drowsy.
  2. Know when you are in a shipping lane–mark them on the charts
  3. Turn on the radar at dark or during the day if in doubt
  4. As soon as another vessel is spotted, note the time and also its compass bearing. Sight it over a stanchion or winch
  5. If it's dark, mark the first-sight spot on the radar screen (get out the Radar Plotting Checklist)
  6. Use binoculars to assess the aspect of a vessel, or at night, to identify its lights (range lights and red/green navigation lights)
  7. Turn engine on if needed to maintain or increase speed
  8. At night, green to your green or red to your red is OK so long as they stay that way
  9. At night, If you see both red and green the other vessel is coming straight at you. Alert the captain, and if immediately necessary turn hard to starboard.
  10. 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]
  11. 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.
  12. Remember what light combinations mean:
  13. 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 Captain and assume a collision course.
  14. On possible collision course, turn on the Radar and start tracking the target on it.
  15. 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.
  16. 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.
  17. Action taken to avoid another vessel should be taken early and should be obvious
  18. To call on the VHF (16 or 13) 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?"
  19. 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).
  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 PFD 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 your vessel 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 your vessel.
  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 your insurance company as soon as possible



©2004 The Trouser Rollers. All rights reserved.
This page was last modified on:
August 9, 2009