Figure 9-29.Vessel constrained by her draft.
Navigation lights must be exhibited from sunrise
Except when it has been determined that a risk of
collision does not exist, every vessel that hears
apparently forward of the beam the fog signal of another
vessel must reduce her speed to the minimum that she
can be kept on course; take all way off if necessary; or
navigate with extreme caution until the risk of collision
In restricted visibility, lookouts are placed as far
forward and as low to the water as possible. There
must be two at each station, one to serve as the lookout
and the other as the phone talker. They report
everything they see or hear.
All vessels are give-way vessels in restricted
visibility. They are required to maneuver to avoid each
other and to avoid turning towards any fog signals
heard. Only the required fog signals will be sounded
unless vessels sight each other, in which case the
normal steering and sailing whistle signals will be
Each power-driven vessel must have a whistle, a
bell mounted in the forward part of the vessel, and for
a vessel 100 meters or more in length, a gong in the
after part of the vessel. Vessels less than 12 meters are
not required to have the whistle, bell, and gong, but
they must have the means to make an efficient signal.
Types of Sound Signals
A prolonged blast is one of from 4 to 6 seconds in
duration; a short blast is about 1 second in duration.
As can be seen in figure 9-30, fog signals are sounded
at 2-minute intervals unless otherwise noted.
A power-driven vessel making way through the
water in a fog or thick weather of any kind is required
by the International and Inland Rules to sound a
prolonged blast at intervals of not more than 2
minutes. Under both sets of rules, a power-driven
vessel under way but stopped, and having no way on
sounds two prolonged blasts, with about 2 seconds
between them, at intervals of not more than 2 minutes.