Page 158 - Collision Avoidance Rules Guide

no rule, and there could be no rule, that the vessel which receives such an
indication, and thereby has good reason for changing her course should not
do so. (Lord Morris, 1890)

Sedgepool-Parth ia
In the particular conditions and the particular locality where this collision
happened, it would be impossible to say that either vessel was wrong for
altering course to starboard, even though the other vessel was not in sight.
This was a collision which, upon my findings, occurred in a narrow channel,
and in those circumstances, I should be very slow to blame a ship which on
hearing a fog signal from another vessel, apparently approaching in the
opposite direction in the same channel, altered her course to starboard in an
attempt to get more over to her proper side. (Mr Justice Willmer, 1956)
If an alteration of course is made for another vessel which has
not been sighted visually, the signals prescribed in Rule 34 must not
be used.

Maneuvring to get clear

When two power-driven vessels approach one another in fog so that
each hears the fog signal of the other forward of the beam, without
having ascertained that there is no risk of collision, it would seem to
be a minimum requirement that each should stop her engines and run
off her way. Of course it has not been suggested that both vessels
should remain stopped until the fog clears. The best plan would
probably be for one vessel to remain stopped, allowing the other to
manceuvre. However, if one vessel hears the other make a signal of
two prolonged blasts she must not assume that the other vessel will
remain stopped.
In the Achille Lauro-Cornelis B., previously referred to,
Mr Justice Willmer said:
As has been pointed out in more than one of the cases cited to me this morn-
ing, it is wrong to interpret a signal of two long blasts as an invitation. It is
not an invitation to come on past. It is no more than a means of advertising
to other shipping the fact that the vessel is stopped.

If necessary take all way off
The courts have held that vessels navigating without radar should
have reversed their engines after hearing a fog signal forward of the
beam in the following instances:
139