1. INTERNATIONAL RULES FOR PREVENTING COLLISIONS AT SEA - PART C RULES 20 - 31
2008

2. General
Instruction in the various navigation light layouts that may be experienced.
In all examples define what action you would take if the grey mast indicates your vessel’s bow, and the other vessel is on a steady bearing.

3. Rule 20 - Application

4. Rule 20 - Application
Lights shall exhibited from sunset to sunrise, and no other lights shall be exhibited that may be confused with the defined lights.
Navigation lights shall also be exhibited during periods of restricted visibility

5. Rule 21 - Definitions

6. Navigation Lights
1. Masthead light
2. Port side light
3. Starboard side light
4. Stern light
5. Towing light

7. Rule 22 - Visibility of Lights

8. Rule 22 - Visibility of Lights

9. Rule 23 - Power-driven Vessels Underway

10. Power driven vessel, less than 50m in length, underway and making way, seen from starboard

11. Power driven vessel probably greater than 50 metres in length, seen from ahead.

12. Power driven vessel probably greater than 50 metres in length, starboard side open

13. Power driven vessel maybe more than 50 metres in length, port side open

14. Power driven vessel maybe more than 50 metres in length, port side open

15. Submarine, underway and making way, seen from starboard (Yellow all round light 90 flashes per minute)

16. Submarine underway and making way, port side open (Yellow all round light 90 flashes per minute)

17. Non displacement vessel making way, port side open (Yellow all round light 120 flashes per minute)

18. Non displacement vessel possibly greater than 50 m in length, underway and making way, port side open (120 flashes per minute)

19. Rule 24 - Towing and Pushing

20. Towing vessel 50m or less, with length of tow 200m or less, seen from ahead. Tow too small to be seen from this aspect.

21. Tug with tow less than 200m, starboard side open

22. Vessel less than 50 metres in length engaged in towing, with length of tow less than 200 metres seen from port

23. Vessel less than 50 metres in length engaged in towing, with length of tow less than 200 metres seen from port

24. Vessel engaged in towing less than 50m in length, with length of tow greater than 200m, starboard side open

25. Vessel engaged in towing possibly greater than 50m in length, with length of tow less than 200m, starboard side open

26. Tug with tow less than 200m, port side open

27. Vessel engaged in towing, with tow, seen from aft

28. Vessel engaged in towing, with tow, seen from aft

29. Tug with tow less than 200m, starboard side open, pushing but not composite unit

30. Tug with tow exceeding 200 metres, starboard side open, towing a log boom

31. Vessel engaged in towing, probably a log boom, seen from astern

32. Vessel engaged in towing possibly greater than 50m in length, with length of tow greater than 200m, starboard side open

33. Vessel engaged in towing, seen from astern, and the tow seen from starboard

34. You could be in risk of collision, and in grave danger

35. Rule 25 – Sailing Vessels Underway and Vessels Under Oars

36. Sailing vessel, port side open, showing optional lights

37. Sailing vessel seen from ahead

38. Sailing vessel less than 20 metres in length seen from ahead, with combined lantern at masthead

39. Sailing Vessel from astern

40. Sailing vessel with mast head lantern, seen from starboard

41. Rule 26 - Fishing Vessels

42. Fishing vessel engaged in fishing under 50 metres in length, starboard side open

43. Fishing vessel engaged in trawling, underway less than 50 metres in length, port side open

44. Fishing vessel less than 50m in length, engaged in fishing, seen from starboard

45. Fishing vessel engaged in fishing under 50 metres in length, port side open

46. Vessel engaged in trawling, underway maybe 50 metres or more than in length, seen from ahead

47. Vessel engaged in trawling, underway maybe 50 metres or more in length, port side open

48. Fishing vessel engaged in trawling, underway less than 50 metres in length, seen from ahead

49. Fishing vessel engaged in trawling, underway possibly greater than 50 metres in length, seen from ahead

50. Fishing vessel engaged in trawling, less than 50 metres in length, with outlying gear, starboard side open

51. Vessel engaged in trawling, underway less than 50 metres in length, port side open, with gear out towards white light

52. Two fishing vessels engaged in fishing, one with outlying gear, seen from starboard side

53. Rule 27 - Vessels Not Under Command or Restricted in Their Ability to Manoeuvre

54. Vessel not under command, underway

55. Vessel, not under command, underway and making way, seen from ahead

56. Vessel not under command, underway and making way, starboard side open

57. Vessel underway and making way, not under command, port side open.

58. Vessel probably over 50 metres in length, restricted in ability to manoeuvre, starboard side open

59. Vessel engaged in towing, under 50 metres in length, restricted in ability to manoeuvre, starboard side open, probably a log boom

60. Vessel engaged in towing less than 50m in length, with length of tow greater than 200m, restricted her ability to manoeuvre starboard side open

61. Vessel restricted in her ability to manoeuvre, head on, with obstructions on her starboard side

62. Vessel restricted in her ability to manoeuvre, head on, with obstructions on her starboard side and clear on her port side

63. Vessel restricted in her ability to manoeuvre, seen from astern, underway or at anchor, with obstruction on her port side

64. Minesweeping vessel, probably 50 metres or more in length, port side open

65. Two power driven vessels, probably greater than 50 metres in length, underway and making way, restricted in their ability to manoeuvre, seen from starboard - probably replenishing at sea

66. Rule 28 - Vessels Constrained by Their Draft

67. Power driven vessel maybe more than 50 metres in length, underway and making way, starboard side open, constrained by her draft

68. Power driven vessel maybe more than 50 metres in length, port side open, constrained by her draft

69. Power driven vessel, seen from astern, constrained by her draft

70. Rule 29 - Pilot Vessels

71. Vessel on pilotage duty, seen from ahead

72. Vessel on pilotage duty, underway, starboard side open

73. Vessel on pilotage duty underway, and making way, seen from astern

74. Pilot vessel, port side open, alongside power driven vessel possibly greater than 50 metres in length, both underway and making way

75. Rule 30 - Anchored Vessels and Vessels Aground

76. Vessel at anchor possibly greater than 50 metres in length, starboard side

77. Vessel at anchor, with decklights, or power driven vessel underway and making way, showing improper decklights

78. Vessel aground, seen from either end It could also be a vessel not under command seen from astern

79. Vessel aground, starboard side open

80. Vessel aground, port side

81. Rule 31 - Seaplanes

82. Seaplane, seen head on

83. Others

84. Power driven or sailing vessel underway from astern
Vessel less than 6 metres underway
Any masthead light just above horizon
Vessel being towed from astern (look for the tow)
Vessel at anchor 50 metres or less

85. Vessel in distress