71
7.6.1.1 Flowmeter
In the event of failure of the discharge flow metering system, the flow rate should be estimated by
the best means available and entered into the MCU manually as described above.
The flowrate can be estimated by:
cargo pump characteristic curves, a copy of which should be included in this manual;
in the case of reciprocating pumps, the flow rate can be calculated by multiplying the number
of strokes per minute x the number of cylinders x the volume per cylinder;
alternatively, the flow rate can be calculated by taking ullage readings from the tank being
discharged at various intervals and using the ullage tables to calculate the flow rate.
7.6.1.2 Ship’s speed indicator
In the event of failure of the ship’s speed indicating device, the speed should be estimated by the
best means available and entered into the MCU manually as described in section 7.6.1.
The speed can be estimated by:
the ship’s speed log;
the main engine rpm.;
from the charted ship’s positions.
7.6.1.3 Oilcon
®
Oil Discharge Monitoring and Control System
In the unlikely event of failure of measuring cell, the oil content should be estimated by the best
means available and entered into the MCU manually as described in section 7.6.1.
The oil content in ppm cannot be estimated accurately other than with sophisticated test equipment.
However, the following, if all used together, would give a rough indication of oil content.
visual observation of the surface of the water around the ship;
the use of an interface detector in the tank being discharged;
the use of a part flow system where fitted.
7.6.1.4 Main Control Unit (MCU)
In the event of failure of the MCU, the following should be carried out:
1. discharge rate calculated by the following formula:
1000
v
QC
R
Where:
R = Discharge rate in litres per nautical mile
C = Oil content in ppm
Q = Flow rate in m³ per hour
v = Ship’s speed in knots
2. discharge total can be calculated by the following formula:
tvROD
Where:
OD = Oil discharged in litres
R = Discharge rate in litres per nautical mile
v = Ship’s speed in knots
t = Discharge time in hours
3. discharge control can be carried out by manual operation of valves and pumps. This can
also be done in the event of failure of the discharge valve actuating circuits or cargo pump
trips.
4. manual recording of all data, calculations, times and operations in the Oil Records Book.
To Next Page
Loading...