3.27 FINISHING THE LOADING
The completion of loading requires close attention at a time when
the chief officer and many of his crew are likely to be fatigued. The
stress of the loading operation, bad weather, mechanical problems, shore
terminal delays, taking on and stowing stores, assisting surveyors and
inspectors and the social diversions of the port may leave the deck
watch less than fully alert.
To avoid errors due to fatigue, cargo officers should take advantage
of any opportunities to rest while off watch, particularly if they are
scheduled to be on watch to complete loading.
The master should be aware of the hours his chief officer and watch
officers have worked. Watch officers who have put in long and hard hours
of cargo operations just before undocking, should not be permitted to
stand a navigation watch immediately after departure.
3.27.1 Giving shore notice
As the end of the loading operation approaches, the cargo watch officer
should re-check the loading plan and chief officer's night orders to
verify when the chief officer wishes to be called, the advance notice
required by the shore and the ship stop gauge required for any line
displacement. A final check of the loading temperature should be made
to ensure that the indicated temperature is being maintained. If the
temperature is lower then promised, the final tank ullage(s) may need
to be increased to allow for more cargo expansion en route.
The shore notice required is the minimum notice. If possible
more notice should be given. The notice to standby should be given in
a clear form; simply saying 'standby' is not sufficient. Notice should
be given in full detail, such as:
'Neverspill cargo control to berth 3; standby to stop loading
fuel oil in twenty minutes.'
The terminal operator must acknowledge the call. If no acknowledgement
is received in thirty seconds, repeat the call. If no acknowledgement
is received to the second call, try the alternate means of communication,
meanwhile directing the deck watch to stand by the emergency shore stop
button (if provided).
It is desirable to provide a ten-minute reminder to the terminal operator
and another reminder five minutes before finish loading.
Final shore stop is given one or two centimetres before reaching the
desired ullage in the final trim tank.
3.27.2 Shore line displacements
If the loading plan includes a shore final line displacement onto the
ship, the manifold valve and all tank valves should be left open after
stopping cargo. The terminal operator will advise the ship when the
displacement has been started. Nevertheless the cargo watch officer
should keep a close watch on the ullage in the final trim tank in case
the shore displacement is started without notice.
The shore should be closely advised of the volume remaining to load
as the displacement nears completion and the ship should advise when
the displacement has been completed according to ship gauges. If the
final tank is slack, it is of little concern if the shore exceeds the
planned displacement quantity by some small amount. This may be desirable
to ensure that the shore line is properly cleared. But if the ship's
final tank is to be full at the end of the displacement, then the cargo
watch officer must call a loading stop when the desired ullage is reached.
If the ship is inadvertently overloaded by a small amount due to a slow
shore shutdown, then the chief engineer can be asked to discharge some
fresh water before departing.
3.27.3 Blowing down/draining loading lines
After the flow of cargo has stopped and the shore valve is closed, the
hoses or arms must be cleared of cargo before disconnecting them. It
is still the practice in some terminals to clear the loading hoses with
compressed air. The process is made more effective if the ship's manifold
valve is closed while air pressure is built up on the shore end, then
the manifold valve is opened and the rush of compressed air clears the
hose into the ship's tank through the ship's lines and tank suction
valve. If compressed air is forced as far as the tank, it rises through
the cargo as an expanding gas bubble, displacing cargo until it reaches
the surface. If there is insufficient spare ullage at the top of the
tank, oil may be forced out of the vents, causing a spill. To prevent
this from happening the hose should be cleared into a tank with adequate
ullage space and the tank valve should be closed 2/3 to reduce the rate
of flow into the tank.
If loading arms were used, the shore personnel will operate the top
vent on the arm, permitting the arm to drain into the ship's tanks and
back to the shore containment. It will then be free of liquid and properly
balanced for disconnecting.
After hoses/arms are drained, the ship's manifold valve can be closed.
3.27.4 Draining deck lines
After the manifold valve is closed, the ship's deck lines should be
drained into the final cargo tanks loaded. Open the vent line at the
manifold, (if there is no vent line, a sample line inboard of the manifold
valve will suffice) and observe that air is being drawn into the vent.
Leave the vent open until draining is complete but do not forget to
close it! If deck lines are not drained, the cargo may expand when heated
by the sun, damaging the cargo lines or valves. If lines are closed
off containing heated cargo, it may contract in the lines, creating
a vacuum which will damage the dresser coupling seals.
In non-inerted ships, when deck lines have been drained, the P/V valve
to the last tank may be closed. Verify that all other P/V valves have
also been returned to the automatic position.
3.27.5 Closing valves and clearing pumproom lines
When the deck lines have been drained, all cargo valves should be closed.
This includes all block valves on deck and in the pumproom. If high
pour oil has been loaded through the pumproom, the pumproom risers must
be either displaced to the cargo tank with lighter product, or pumped
down immediately after loading, transfering the contents to a suitable
cargo tank or to the slop tank. Failure to strip all high-pour oil from
the pumproom lines may result in blocked lines at the discharge port.