LIGHTS AND SHAPES
Rules for lights must be complied with in all
weather, from sunset to sunrise, as specified by both
International and Inland Rules of the Road.
Navigational lights and dayshapes of another
vessel convey information such as clues to the type
and size of vessel, its heading in relation to your
vessel, type of operation in which it may be engaged,
and other data that is helpful in determining right of
way and preventing a collision.
Various navigational light and dayshape displays
prescribed by the rules are discussed in the following
When the rules refer to a power-driven vessel,
they mean one propelled by any kind of machinery, as
distinct from a sailing ship under sail. A vessel under
way means a ship not at anchor, not made fast to the
shore, or not aground. The ship does not actually have
to be making headway.
Both rules state that the rules for lights must be
complied with in all weather from sunset to sunrise, and
should also be exhibited from sunrise to sunset in
restricted visibility. These lights may be exhibited in all
other circumstances when it is deemed necessary. Ships
usually are darkened during wartime conditions; but
even then, lights are kept ready for immediate display.
MASTHEAD LIGHT.You are aware that a
power-driven vessel underway carries a white light
(masthead light) placed over the fore and aft centerline
of the vessel, showing an unbroken light over an arc
of the horizon of 225° and so fixed as to show the light
from right ahead to 22.5° abaft the beam on either side
of the vessel. The light at the fore masthead, or some
other elevated point forward, is between 20 and 40 feet
above the deck. This light must be visible from 2 to 6
miles, depending on the length of the vessel. You
know, too, that under both rules, a power-driven vessel
over 50 meters in length shows another white light aft,
at least 15 feet higher than the fore masthead light. The
horizontal distance between these lights should not be
less than one-half the length of the vessel but need not
be more than 100 meters. The after light, called the aft
masthead light, is mandatory under both rules except
for vessels less than 50 meters in length. A
power-driven vessel less than 12 meters may show an
all-round white light in lieu of the masthead light.
SIDELIGHTS.Sidelights mean a green light
on the starboard side and a red light on the port side,
each showing an unbroken light over an arc of the
horizon of 112.5° and so fixed as to show the light
from right ahead to 22.5° abaft the beam on its
respective side. In a vessel of less than 20 meters, the
sidelights may be combined in one lantern carried on
the fore and aft centerline of the vessel.
Side lights must be visible from 1 to 3 miles,
depending on the size of the vessel. A sailing vessel or
a ship being towed displays side lights and a stern light
onlynever masthead lights. A vessel under oars or a
sailing vessel of less than 7 meters in length need carry
only a lantern showing a white light, which it must
exhibit in time to prevent collision. If practicable, a
sailing vessel of less than 7 meters must exhibit the lights
prescribed for a sailing vessel under way.
STERNLIGHT. A white light placed as nearly
as practicable at the stern, showing an unbroken light
over an arc of the horizon of 135° and so fixed as to
show the light 67.5° from right aft on each side of the
TOWING LIGHT.The towing light is a yellow
light having the same characteristics as a sternlight.
Lights, Pilot Vessels
An OOD or conning officer often is most anxious
to sight the pilot boat and signal it alongside without
being forced to lie to when conditions may be setting
the ship toward a lee shore. Signalmen should
recognize a pilot vessel the instant it is sighted.
Pilot vessels, when engaged on their stations on
pilotage duty, should not show the lights required for
other vessels. A pilot vessel should exhibit at or near
the masthead two all-round lights in a vertical line, the
upper being white and the lower red, and when under
way (fig. 9-22), in addition, sidelights and a sternlight.
When at anchor, in addition to those lights previously
described, the pilot vessel should show the anchor
light, lights, or shape prescribed for anchored vessels.
The daytime display for a pilot vessel is the display of
the HOTEL flag.
Pilot vessels, when not engaged on pilotage duty,
should exhibit the lights or shapes prescribed for
similar vessels of their length.
Vessel at Anchor
A vessel at anchor (fig. 9-23) should show, where
it can best be seen, an all-round white light or one ball
in the forepart of the vessel, and, at or near the stern,