Page 121 - Collision Avoidance Rules Guide

A vessel which is constrained by her draught is permitted to exhibit
the lights or shapes prescribed in Rule 28 to indicate her limited
manceuvrability but is not relieved of her obligation to comply with
the other Rules of this Section as a power-driven vessel (see page
121). A vessel constrained by her draught is, therefore, expected to
keep out of the way of a power-driven vessel which is crossing from
her starboard side so as to involve risk of collision. Other vessels
should take full account of the limited manceuvrability of a vessel
constrained by her draught in considering whether to take early action
to allow sufficient sea room for safe passage in accordance with Rule
8(f) (see page 58) or when to take action in accordance with Rule 17
(see pages 1067).

Avoid crossing ahead
The requirement to avoid crossing ahead only applies in a crossing
situation in which there is risk of collision. It does not apply at long
ranges, before risk of collision begins to apply, or to cases in which
the bearing is appreciably changing. If there is a possibility of risk of
collision the give-way vessel must avoid crossing ahead.

King Stephen-Ashton
The only way in which the defendants can escape from liability, if these
Rules apply, is by showing that the vessels were not crossing so as to involve
risk of collision. . . . The question I have to consider is whether it can be said
that at the outset there was no risk of collision. The ground upon which the
defendants put it must be that having regard to their speed, and the other
vessel approaching them at a slower speed on their starboard side, there
really was no risk of collision. That is a view that neither I nor the Elder
Brethren can accept, because, although it is said that the vessel broadened,
she broadened very slightly. . . . The defendants were within those Rules,
and their vessel ought not to have attempted to cross ahead of the other ship.
(Sir Gore11 Barnes, 1905)
In a crossing situation a power-driven vessel is required to avoid
crossing ahead of a power-driven vessel on her own starboard side, if
there is risk of collision, but is not directed to cross astern. An altera-
tion of course to starboard will usually be the best method of keeping
out of the way of a vessel which is on the starboard bow, but a reduc-
tion of speed or a substantial alteration of course to port would be
preferable in order to avoid collision with a vessel approaching from
near the starboard beam (see page 52).
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