1) The document discusses Part C Rules 20-31 of the navigational light layouts that ships use at sea. 2) It provides examples of what various ship configurations would look like at night based on their navigation light positioning. 3) For each example, the reader is instructed to identify what action they would take if the ship in the example was on a steady bearing relative to their own ship, represented by the grey mast.

1. © Grunt Productions 2007
Navigational Lights
Part C Rules 20-31
A brief by Lance Grindley

2. © Grunt Productions 2007
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. © Grunt Productions 2007
Rule 20 - Application

4. © Grunt Productions 2007
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. © Grunt Productions 2007
Rule 21 - Definitions

6. © Grunt Productions 2007
Navigation Lights
1. Masthead light
2. Port side light
3. Starboard side light
4. Stern light
5. Towing light

7. © Grunt Productions 2007
Rule 22 - Visibility of Lights

8. © Grunt Productions 2007
Rule 22 - Visibility of Lights
Masthead
light
Sidelight Sternlight Towing light All round
red white,
green or
yellow light
Length 50
metres or
more
6 miles 3 miles 3 miles 3 miles 3 miles
Length less
than 50 but
12 metres
or more
5 miles 2 miles 2 miles 2 miles 2 miles
Length less
than 20 but
12 metres
or more
3 miles 1 mile 2 miles 2 miles 2 miles
Length less
than 12
metres
2 miles 1 mile 2 miles 2 miles 2 miles

9. © Grunt Productions 2007
Rule 23 - Power-driven Vessels
Underway

10. © Grunt Productions 2007
Power driven vessel, less than 50m in length,
underway and making way, seen from starboard

11. © Grunt Productions 2007
Power driven vessel probably greater than 50
meters in length, seen from ahead.

12. © Grunt Productions 2007
Power driven vessel probably greater than 50 meters
in length, starboard side open

13. © Grunt Productions 2007
Power driven vessel maybe more than 50 meters in
length, port side open

14. © Grunt Productions 2007
Power driven vessel maybe more than 50 meters
in length, port side open

15. © Grunt Productions 2007
Submarine, underway and making way, seen from
starboard
(Yellow all round light 90 flashes per minute)

16. © Grunt Productions 2007
Submarine underway and making way, port side
open
(Yellow all round light 90 flashes per minute)

17. © Grunt Productions 2007
Non displacement vessel making way, port side
open
(Yellow all round light 120 flashes per minute)

18. © Grunt Productions 2007
Non displacement vessel possibly greater than 50 m
in length, underway and making way, port side
open (120 flashes per minute)

19. © Grunt Productions 2007
Rule 24 - Towing and Pushing

20. © Grunt Productions 2007
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. © Grunt Productions 2007
Tug with tow less than 200m, starboard side open

22. © Grunt Productions 2007
Vessel less than 50 meters in length engaged in
towing, with length of tow less than 200 meters seen
from port

23. © Grunt Productions 2007
Vessel less than 50 meters in length engaged in
towing, with length of tow less than 200 meters
seen from port

24. © Grunt Productions 2007
Vessel engaged in towing less than 50m in length,
with length of tow greater than 200m, starboard side
open

25. © Grunt Productions 2007
Vessel engaged in towing possibly greater than 50m
in length, with length of tow less than 200m,
starboard side open

26. © Grunt Productions 2007
Tug with tow less than 200m, port side open

27. © Grunt Productions 2007
Vessel engaged in towing, with tow, seen from aft

28. © Grunt Productions 2007
Vessel engaged in towing, with tow, seen from aft

29. © Grunt Productions 2007
Tug with tow less than 200m, starboard side open,
pushing but not composite unit

30. © Grunt Productions 2007
Tug with tow exceeding 200 meters, starboard side
open, towing a log boom

31. © Grunt Productions 2007
Vessel engaged in towing, probably a log boom,
seen from astern

32. © Grunt Productions 2007
Vessel engaged in towing possibly greater than 50m
in length, with length of tow greater than 200m,
starboard side open

33. © Grunt Productions 2007
Vessel engaged in towing, seen from astern, and
the tow seen from starboard

34. © Grunt Productions 2007
You could be in risk of collision, and in grave
danger

35. © Grunt Productions 2007
Rule 25 - Sailing Vessels Underway
and Vessels Under Oars

36. © Grunt Productions 2007
Sailing vessel, port side open, showing optional
lights

37. © Grunt Productions 2007
Sailing vessel seen from ahead

38. © Grunt Productions 2007
Sailing vessel less than 20 meters in length seen
from ahead, with combined lantern at masthead

39. © Grunt Productions 2007
Sailing Vessel from
astern

40. © Grunt Productions 2007
Sailing vessel with mast head lantern, seen from
starboard

41. © Grunt Productions 2007
Rule 26 - Fishing Vessels

42. © Grunt Productions 2007
Fishing vessel engaged in fishing under 50 meters
in length, starboard side open

43. © Grunt Productions 2007
Fishing vessel engaged in trawling, underway less
than 50 meters in length, port side open

44. © Grunt Productions 2007
Fishing vessel less than 50m in length, engaged in
fishing, seen from starboard

45. © Grunt Productions 2007
Fishing vessel engaged in fishing under 50 meters in
length, port side open

46. © Grunt Productions 2007
Vessel engaged in trawling, underway maybe 50
meters or more than in length, seen from ahead

47. © Grunt Productions 2007
Vessel engaged in trawling, underway maybe 50
meters or more in length, port side open

48. © Grunt Productions 2007
Fishing vessel engaged in trawling, underway less
than 50 meters in length, seen from ahead

49. © Grunt Productions 2007
Fishing vessel engaged in trawling, underway
possibly greater than 50 meters in length, seen
from ahead

50. © Grunt Productions 2007
Fishing vessel engaged in trawling, less than 50
meters in length, with outlying gear, starboard side
open

51. © Grunt Productions 2007
Vessel engaged in trawling, underway less than 50
meters in length, port side open, with gear out
towards white light

52. © Grunt Productions 2007
Two fishing vessels engaged in fishing, one with
outlying gear, seen from starboard side

53. © Grunt Productions 2007
Rule 27 - Vessels Not Under
Command or Restricted in Their
Ability to Maneuver

54. © Grunt Productions 2007
Vessel not under command, underway

55. © Grunt Productions 2007
Vessel, not under command, underway and
making way, seen from ahead

56. © Grunt Productions 2007
Vessel not under command, underway and making
way, starboard side open

57. © Grunt Productions 2007
Vessel underway and making way, not under
command, port side open.

58. © Grunt Productions 2007
Vessel probably over 50 meters in length, restricted
in ability to maneuver, starboard side open

59. © Grunt Productions 2007
Vessel engaged in towing, under 50 meters in
length, restricted in ability to maneuver, starboard
side open, probably a log boom

60. © Grunt Productions 2007
Vessel engaged in towing less than 50m in length,
with length of tow greater than 200m, restricted her
ability to maneuver starboard side open

61. © Grunt Productions 2007
Vessel restricted in her ability to maneuver, head
on, with obstructions on her starboard side

62. © Grunt Productions 2007
Vessel restricted in her ability to maneuver, head
on, with obstructions on her starboard side and
clear on her port side

63. © Grunt Productions 2007
Vessel restricted in her ability to maneuver, seen
from astern, underway or at anchor, with
obstruction on her port side

64. © Grunt Productions 2007
Minesweeping vessel, probably 50 meters or more in
length, port side open

65. © Grunt Productions 2007
Two power driven vessels, probably greater than 50
meters in length, underway and making way, restricted in
their ability to maneuver, seen from starboard - probably
replenishing at sea

66. © Grunt Productions 2007
Rule 28 - Vessels Constrained by
Their Draft

67. © Grunt Productions 2007
Power driven vessel maybe more than 50 meters in
length, underway and making way, starboard side
open, constrained by her draft

68. © Grunt Productions 2007
Power driven vessel maybe more than 50 meters in
length, port side open, constrained by her draft

69. © Grunt Productions 2007
Power driven vessel, seen from astern, constrained
by her draft

70. © Grunt Productions 2007
Rule 29 - Pilot Vessels

71. © Grunt Productions 2007
Vessel on pilotage duty, seen from ahead

72. © Grunt Productions 2007
Vessel on pilotage duty, underway, starboard side
open

73. © Grunt Productions 2007
Vessel on pilotage duty underway, and making
way, seen from astern

74. © Grunt Productions 2007
Pilot vessel, port side open, alongside power driven
vessel possibly greater than 50 meters in length,
both underway and making way

75. © Grunt Productions 2007
Rule 30 - Anchored Vessels and
Vessels Aground

76. © Grunt Productions 2007
Vessel at anchor possibly greater than 50 meters in
length, starboard side

77. © Grunt Productions 2007
Vessel at anchor, with decklights, or power driven
vessel underway and making way, showing
improper decklights

78. © Grunt Productions 2007
Vessel aground, seen from either end
It could also be a vessel not under command seen
from astern

79. © Grunt Productions 2007
Vessel aground, starboard side open

80. © Grunt Productions 2007
Vessel aground, port side

81. © Grunt Productions 2007
Rule 31 - Seaplanes

82. © Grunt Productions 2007
Seaplane, seen head on

83. © Grunt Productions 2007
Others

84. © Grunt Productions 2007
Power driven or sailing
vessel underway from
astern
Vessel less than 6
meters underway
Any masthead light just
above horizon
Vessel being towed
from astern (look for the
tow)
Vessel at anchor 50
meters or less

85. © Grunt Productions 2007
Vessel in distress