OBQ and ROB

ON BOARD QUANTITY (OBQ): All the oil, water, sludge and sediment in the cargo and associated lines and pumps on a ship before loading a cargo commence. (this term may not apply to product movement).

QUANTITY REMAINING ON BOARD (ROB): All the oil, water, sludge and sediment in the cargo tanks and associated lines and pumps on a ship after discharging a cargo has been completed, excluding vapour but including clingage. (this term may not apply to product movements)

Determine the OBQ/ROB for Liquids as follows:

(1)    By measurement determine the depth of liquid in each tank. Measure-ments should be taken at as many points as possible to ascertain if the liquid covers the tank bottom.

(2)    Where there is a sufficient depth of liquid determine its temperature. If not assume the material to be at standard temperature.

(3)    Calculate and record corrected volumes using where appropriate :

(a)    Special dip tables or the wedge formula if the liquid does not cover the bottom of the tank.

(b)   Trim/list corrections if the liquid covers the bottom of the tank.

Note: When applicable, estimate the volumes of oil residues adhering to the surfaces of the tank walls and structure. Add this volume to the quantities determined above.

(4)    Where possible obtain a sample of the OBQ/ROB.

Note:

Slops which are to be loaded on top should be included in the OBQ/ROB report. Record on the report from the nature of the materiel and the method used to determine the volume in each compartment. Material in compartments not receiving cargo should also be measured and reported on an OBQ/ROB report from.

This report should be signed by the interested parties. If the vessels officer signed under protest a note shall be made as to whether the vessel chose to have a survey made by another company on its behalf .It is strongly recommended that Dry Tank Certificates are not signed by inspectors. Refer to specific instructions issued by interested parties concerning Dry Tank Certificates.

If there is an unresolved dispute between the vessels personnel and the inspector or other interested parties as to the quantity and character (liquid or non-liquid) of the ROB this shall be reported immediately by telephone or telex to all the parties concerned and noted on the OBQ/ROB report.

Posted in: Chemical Engineering Processing

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