See unitsPollution prevention on ships: oil record book, garbage plan, SOPEP, ballast water and emission control areas
The oil record book and the oil discharge limits
1The lesson in plain words
Record oil operations fully and without delay. Discharge only when all MARPOL conditions are met, through approved equipment while en route.
Who needs it
MARPOL Annex I covers oil. Gross tonnage (GT) measures enclosed volume, not weight. Every oil tanker of 150 GT or more and every other ship of 400 GT or more carries an oil record book (ORB) Part I for machinery-space operations. Oil tankers of 150 GT or more also carry Part II for cargo and ballast operations.
Part I codes
Each entry starts with a code letter. A ballasting or cleaning of fuel oil tanks. B discharge of dirty ballast or cleaning water from those tanks. C collection, transfer and disposal of oil residues (sludge). D non-automatic discharge or disposal of bilge water. E automatic discharge of bilge water. F condition of the oil filtering equipment. G accidental or other exceptional discharges. H bunkering (taking on fuel) or receiving bulk lube oil. I other operations and remarks.
Part II
Part II records cargo and ballast work on a tanker: loading, internal transfer and unloading of cargo, crude oil washing, ballasting of cargo tanks, tank cleaning, discharge of dirty ballast and of water from slop tanks, and the condition of the oil discharge monitoring and control system (ODMCS), the equipment that measures and limits oil discharged from the cargo area.
Signing and keeping
Record each operation fully and without delay. The officer or officers in charge sign each entry, and the master signs each completed page. Keep the book on board, readily available for inspection, for 3 years after the last entry. Since 1 October 2020 an electronic record book approved by the flag may replace the paper book. Port state officers may inspect it and take certified copies.
Machinery-space discharges
Discharge only while en route (proceeding on passage), through approved filtering equipment, at 15 ppm (parts per million) or less without dilution. Tanker bilges must not come from cargo pump rooms or contain cargo residues. Ships of 10,000 GT or more need a 15 ppm alarm and automatic stopping device; in special areas, so do ships of 400 GT or more. No oily discharge is allowed in Antarctic waters or, for ships subject to the Polar Code, Arctic waters. Otherwise retain the water and land it ashore.
Tanker cargo-area discharges
Outside special areas, discharge only while en route, more than 50 nautical miles (NM) from the nearest land, with the ODMCS operating and slop tanks (tanks for oily cargo mixtures) in use. The instantaneous rate of oil, not the whole mixture, must not exceed 30 litres per nautical mile. Total oil discharged must not exceed 1/30 000 of the cargo from which the residue came. Example: 90,000 t of cargo ÷ 30,000 = 3 t of oil in total.
2Key data
- ORB Part I
- Oil tankers ≥150 GT; other ships ≥400 GT
- ORB Part II
- Oil tankers ≥150 GT (cargo and ballast operations)
- Kept
- 3 years after last entry; approved electronic books since 1 Oct 2020
- Machinery-space limit
- ≤15 ppm; en route; filter/alarm/stops as required; polar bans
- Tanker cargo area
- Outside special areas: >50 NM; en route; oil ≤30 L/NM, ≤cargo/30 000
- Worked example
- 90,000 t cargo ÷ 30,000 = 3 t oil ceiling, if other conditions met
3Key points
- 1
Part I for machinery spaces; Part II for tanker cargo and ballast.
- 2
Officer signs each entry; the master signs each completed page.
- 3
Keep the ORB 3 years; approved electronic books allowed since 2020.
- 4
Bilge: ≤15 ppm, en route, approved filter; required alarm/stop. No oil discharge in Antarctic or covered Arctic waters.
- 5
Outside special areas: >50 NM, en route; ≤30 L oil/NM, total oil ≤1/30 000 of the cargo; ODMCS operating.
4Frequent mistakes
Wrong: Record the sludge transfers at the end of the week, all together.
Right: Record each operation without delay, with its code, and have the officer in charge sign it.
Wrong: Bilge water at 15 ppm may be pumped out while the ship is at anchor.
Right: The ship must be en route. At anchor or alongside, keep it on board or land it.
Wrong: The 1/30 000 limit applies to each separate discharge.
Right: It limits the total oil discharged, compared with the cargo the residue came from; all other discharge conditions still apply.
5Practice case & exam keys
On passage, the oil filtering equipment's 15 ppm alarm sounds and the three-way valve recirculates. The second engineer suggests bypassing the alarm so the bilge tank can be emptied before arrival. What do you do?
Show the answer
Refuse the bypass. Stop discharge, retain the bilge water and investigate the alarm. Tell the chief engineer and master. Record what actually happened under the applicable bilge-operation code, D or E; use F for any confirmed equipment failure and G for any accidental or exceptional discharge. Make truthful entries and arrange disposal ashore if needed.
Exam keys
- ORB Part I: oil tankers ≥150 GT, other ships ≥400 GT; Part II: oil tankers ≥150 GT.
- Codes A–I in Part I; officer signs each entry, master each page; kept 3 years.
- Machinery spaces: ≤15 ppm, en route, approved filter; required alarm and automatic stop. No oil discharge in Antarctic waters or, for Polar Code ships, Arctic waters.
- Outside special areas: >50 NM, en route, ≤30 L oil/NM, total oil ≤1/30 000 of the cargo, ODMCS operating.
Finish this unit
When you've read it, answer three questions. Get all three right to finish the unit; opening the page alone doesn't count.
My notes for this unit
No notes