Rule 15 - Crossing situation

When two power-driven vessels are crossing so as to involve

risk of collision, the vessel which has the other on her own
starboard side shall keep out of the way and shall, if the
circumstances of the case admit, avoid crossing ahead of
the other vessel.

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 Rule 15 - Crossing situation
Rule 15 is part of Section II ‘’Conduct of Vessels in Sight of
One Another
When not in sight of one another (in restricted
visibility), Rule 19 applies

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 Rule 15 - Crossing situation
Application
Rule 15 Only applies to two power-driven
vessels crossing.
Rule 15 does not apply to:
−  Two sailing vessels
−  A sailing vessel and a power-driven vessel
−  A power-driven vessel and a hampered vessel such as:
•  a vessel not under command
•  a vessel restricted in her ability to manoeuvre
•  a vessel constrained by her draught
•  a vessel engaged in fishing
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Rule 15 - Crossing situation

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 Rule 15 - Crossing situation

Crossing situation
§  Vessels are near one another so that there
is risk of collision
§  Vessel is between half a compass point
ahead to two compass points abaft the beam
§  Vessel’s courses cross one another.

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 Rule 15 - Crossing situation
Crossing sector
The crossing sector is
nearly equal to the sector
of the starboard sidelight.

Crossing sector From half a compass point

ahead to two compass
points abaft the beam

Your vessel is the give way-

vessel.
Any vessel in sight in that
sector and crossing is a stand-
on vessel 6
 Rule 15 - Crossing situation
Action to be taken

Rule 15 does not say which action

should be taken by the give-way vessel

It only says that the give-way vessel

should keep out of the way and
recommends not to cross ahead of the
stand-on vessel Stand-on vessel

Give-way vessel 7
 Rule 15 - Crossing situation
Recommended action

Give way vessel should alter

course to starboard to pass
behind stand-on vessel Stand-on vessel should
keep her course and speed
Give one short blast on whistle

(Abt.) sector
Danger Stand-on vessel
of abt. 112,5°

Give-way vessel 8
 Rule 15 - Crossing situation
Recommended action

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 Rule 15 - Crossing situation
Recommended action

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 Rule 15 - Crossing situation
Recommended action

As seen from the bridge

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 Rule 15 - Crossing situation
Recommended action

Own vessel alters course to

starboard to pass astern of other
vessel

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 Rule 15 - Crossing situation
Recommended action

Other vessel is now on port side

and clear

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 Rule 15 - Crossing situation
Recommended action

MESSINA STRAIT

The ferry is altering to starboard

to pass astern of the containership

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 Rule 15 - Crossing situation
Alternative action

Avoid
§  Crossing ahead of the other vessel
§  Apply a course alteration to port only for a
vessel approaching from near the starboard
beam.
§  Apply a course alteration to starboard for a
vessel approaching ahead of the starboard
beam

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 Rule 15 - Crossing situation
Alternative action

If passing astern is impossible

− Reduce speed, possibly stop and reverse

engines (sound three short blasts) OR
− Alter course to port to follow a parallel course

OR
− Make a complete turning circle to port

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Rule 15 - Crossing situation

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 Rule 15 - Crossing situation
Alternative action
Avoid crossing ahead of the other vessel

In a crossing situation, it is •  alter to Sb: not enough room

not an obligation to alter
•  reduce speed: not easy if
the course to starboard
engine on «engine control»
•  turn to port:
interesting if speed of B
Ship A must giveway: much bigger than speed
of A
− alter course to Sb?
Not advised
− reduce speed
− alter to port untill B is
passed and clear B
A 18
Rule 15 - Crossing situation

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 Rule 15 - Crossing situation
Alternative action
«…avoid crossing ahead of the other vessel»

Ship A must giveway:

another possibility is to
make a 360° turn to port
EMERGENCY

A
B 20
 Rule 15 - Crossing situation
Alternative action

Give-way vessel had to

make a 360° turn to port

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 Rule 15 - Crossing situation
Safe distance

This is a good distance at which to keep out

of the way when there is risk of collision

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© travelpod.com
 Rule 15 - Crossing situation
Safe distance

On the open sea, this is definitely NOT a safe passing distance

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© green.autoblog.com
 Rule 15 - Crossing situation
Safe distance

Passing too close or taking action too

late will inevitably lead to a collision

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© cclausen.netship.com
 Rule 15 - Crossing situation
Safe distance

No comments

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© gcaptain.com
 Rule 15 - Crossing situation
Special situations

In normal conditions this is not considered as a safe passing

distance

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 Rule 15 - Crossing situation
Special situations

1.  The hoovercraft is much faster than the power-driven

vessel proceeding at ‘’dead slow ahead’’
2.  This is a narrow channel where it is normal for ships to
pass closer to each other

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 Rule 15 - Crossing situation
Special situations

Again, the big difference of speed between the

hoovercraft and the power-driven vessel justifies the
manoeuvre

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 Rule 15 - Crossing situation
Special situations

Here, the distance between the two vessels is a safe distance

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 Rule 15 - Crossing situation
DANGEROUS SITUATION

The coaster is not complying with Rule 15

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 Rule 15 - Crossing situation
DANGEROUS SITUATION

Due to the closeness of the coaster and the presence of deck

cargo, the OOW hardly sees the vessel ahead

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 Rule 15 - Crossing situation
Other vessels

Rule 15 must also be complied between two vessels

engaged in fishing

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 Rule 15 - Crossing situation
Narrow channel
A vessel shall not cross a narrow channel or fairway if such crossing
impedes the passage of a vessel which can safely navigate only within
such channel or fairway

If a risk of collision develops between a crossing vessel coming from

starboard and a vessel navigating within the channel, the latter must
comply with rule 15 and give way. (The same applies to a TSS)
Rule 15 does not relieve the crossing vessel of her obligation
‘’not to impede’’
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 Rule 15 - Crossing situation
Remarks

−  When an alteration of course is made to avoid risk of collision, this

alteration should be substantial (especially for a vessel approaching
from abeam or near)
−  Large alterations of course (40° to 60° or more) are rapidly noticed
visually and on the radar
−  Avoid small alterations of courses (about 5°). These are usually
mistaken for the yawing of the vessel.
−  A change of speed is not a favorite manœuvre for many seamen
but can prove very useful in many situation
−  It is safer to pass another vessel too far than too close
−  It is usually safer to turn away from a vessel than going nearer to it
−  Do not hesitate to make the required sound signals
−  Use your AIS and make proper use of your VHF if necessary
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 Rule 15 - Crossing situation
A breach of the Rules

Vessel A is the give-way vessel and

should avoid crossing ahead of vessel B

A
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 Rule 15 - Crossing situation
A breach of the Rules

Vessel A choses to alter course to port

and increases her speed in order to
pass ahead of B

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 Rule 15 - Crossing situation
A breach of the Rules

The CPA between the two vessels 3

in situation 3 is about 0,5 mile

Is this a safe passing distance ?

It is certainly not a good avoiding action 37