Oil Record Book — Part I (Machinery Space Operations)
Prescribed ORB Part I operations: codes, weekly inventory, signatures and record retention.
Operational Explanation
The Oil Record Book (ORB) Part I records the machinery-space operations prescribed by regulation 17 and appendix III: ballasting and cleaning of fuel tanks, discharge of bilge water, condition of the oil filtering equipment, bunkering of fuel and bulk lubricating oil, collection and disposal of oil residues, and relevant transfers. Not every internal fuel or lubricating-oil transfer automatically requires an ORB entry: distinguish prescribed MARPOL entries from additional SMS records. The Oil Discharge Monitoring and Control System (ODMCS) belongs to cargo/ballast operations on oil tankers and is recorded in Part II, not here.
The ORB supports Port State Control verification of recorded operations and quantities. Consistency with tanks, equipment and disposal documents helps officers investigate discrepancies.
Regulatory Reference
MARPOL Annex I, Regulation 17 (Oil Record Book Part I) and Appendix III (standard format). Implementation guidance in MEPC.1/Circ.736/Rev.2 (2011) — "Guidance for the recording of operations in the Oil Record Book Part I". It is the applicable guidance for entries, and it remains so. The 2019-2020 framework did not introduce a new Appendix III form: it enabled the Electronic Record Book approved by the Administration. Res. MEPC.314(74) amends Annexes I, II and V to that effect, and Res. MEPC.312(74) carries the guidelines. Res. MEPC.316(74) amends Annex VI instead, and does not concern this book.
Scope of Application
Under MARPOL Annex I, Regulation 17.1, Part I is required on every oil tanker of 150 GT and above and on every ship of 400 GT and above other than an oil tanker. There is no applicability criterion based on the presence of an oily water separator: fitting one does not bring a ship below those thresholds within the requirement. Oil tankers of 150 GT and above additionally keep Part II (cargo/ballast operations).
Procedure / How to Complete It
- For ships holding an IOPP Certificate, make entries at least in English, French or Spanish (regulation 17.4). Italian examples on the companion page are training translations, not language templates for the record book.
- Select applicable A–I code and items: distinguish C inventory/collection/disposal, D and E non-automatic/automatic starting, F equipment condition and H bunkering.
- Record without delay after completion; no 24-hour grace period. Include date, code/item and all required particulars: m³ for relevant oily operations, MT for bulk fuel and lubricating-oil bunkering; no arbitrary volume for E.
- Complete the weekly C11 sludge-tank inventory, even without disposals.
- The officer in charge signs each operation; the Master signs each completed page or applicable electronic group. Electronic records require Administration approval.
- Retain each record book on board for at least three years after its last entry, including earlier books still within that period.
Weekly ORB C 11.1–11.3 inventory: for each sludge tank in the IOPP Supplement, identification, capacity in m³ and quantity retained in m³. Training example, no disposals: 07-SEP-2026, tank S1, capacity 10 m³, retained 2 m³; 14-SEP-2026, same tank and capacity, retained 2.8 m³. Each inventory signed by the officer in charge. This is not the SMS monthly balance and does not impose the same weekly inventory on bilge tanks. MEPC.1/Circ.736/Rev.2, examples 1–2; MEPC.187(59), C11.
Diagram: recording flow
Practical Example
Example of a code H — Bunkering entry:
| Date | Code | Item | Entry (summary) |
|---|---|---|---|
| 14-JUL-2026 | H | 26.1–26.3 | Genoa; start 08:00, stop 12:00 UTC. ISO 8217 RMG 380 HFO, 340 MT: 210 MT to FO1 (total 480 MT), 130 MT to FO2 (total 300 MT). Officer-in-charge signature. For bulk lubricating oil use separate 26.4, not 26.3. |
| 14-JUL-2026 | C | 11.1–11.4 | Operator-initiated manual collection example: pumping from separator drain tank to sludge tank S1. 11.1 S1; 11.2 capacity 10 m³; 11.3 retained 2.8 m³; 11.4 collected 0.8 m³, source identified. Officer-in-charge signature. Not automatic inflow or C12 disposal; do not record tank capacity for C12.x. |
The Item column takes the number printed in the list of items in the Oil Record Book itself: a single series running from 1 to 26 across codes A to I (code C: items 11 and 12; code F: items 19 to 21; code H: item 26 with sub-items 26.1–26.4). Notations such as "H1" or "C2", formed by combining the letter with a counter, do not exist in the IMO format: they make the book hard to read during an inspection and are best avoided. The date format is the one the guidance prescribes, dd-MONTH-yyyy: the circular states it expressly and gives its example with the month abbreviated in letters. It removes the day/month ambiguity without inventing a convention, and a month written in letters stays readable to inspectors of any nationality.
What Typically Goes Wrong
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Operation not signed by the officer in charge, or completed page not signed by the Master | PSC deficiency, possible detention | Regulation 17.4 asks for two different signatures: the officer signs each completed operation, the Master each completed page. Close-out check of each page before the end of the month or voyage |
| Entries recorded days late or in bulk | Suspicion of tampering, PSCO follow-up | Record immediately after every operation |
| Untracked erasures or corrections | Loss of the document's credibility, possible offence | Strike through the incorrect entry with a single line, keeping it legible; sign and date the correction, then enter the corrected entry immediately afterwards; never use correction fluid |
| Bilge volumes inconsistent with tank capacity/consumption | Investigation into illegal discharges | Periodic reconciliation between estimated production and recorded volumes |
What the PSCO Checks
Operational Tips
- Never leave the ORB «pending»: Regulation 17.4 requires each operation to be recorded without delay, not by the end of the day.
- Use the applicable code and item number, followed by every particular that Appendix III and the recording guidance require for that item: some of them are necessarily descriptive. The code does not replace the particulars, and an unstructured narrative does not replace a prescribed entry.
- Before a PSC inspection, verify that all recent pages are signed and consistent with the Bunker Delivery Note and the bilge log.
- For an electronic ORB, make sure it has been approved by the flag State Administration.
Preparation checklist
Educational checklist. This summary supports learning and preparation only. It does not replace the vessel’s approved procedures, manuals, statutory documents, company SMS, or applicable official requirements. Completing it demonstrates neither compliance nor readiness for an inspection: it shows that a list has been read, not that the ship is in order. Always verify the current documents carried on board.
- Operations recorded without delay, officer signatures and Master signatures on completed pages.
- Weekly C11 inventories for sludge tanks; units appropriate to each operation.
- Bunkers reconciled with BDN in matching units, without automatically equating m³ with MT.
- No untraceable corrections; each book available for three years after its last entry.
FAQ
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Last substantive revision of this page: 15 September 2026 · page fingerprint d2ff21c6f07a