Operational Guide · Registers & Logbooks

# Oil Record Book — Part I (Machinery Space Operations)

The mandatory logbook documenting every oil-related operation in the machinery space: the first thing a PSCO asks to see on board.

MARPOL Annex I Oil Record Book ORB machinery space PSC

## Operational Explanation

The Oil Record Book (ORB) Part I records all operations involving fuel and lubricating oil carried out in the machinery space: ballasting and cleaning of fuel tanks, discharge of bilge water, condition of the discharge monitoring system (ODMCS/OWS), bunkering and internal transfers.

It is not a secondary administrative form: it is the single most scrutinised document during Port State Control inspections, and one of the main tools authorities use to detect illegal discharges (so-called "magic pipes").

## 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 — "Guidance for the recording of operations in the Oil Record Book Part I".

## Scope of Application

Mandatory for every ship of 400 GT and above, and for any ship fitted with an oily water separator (OWS), regardless of tonnage. Part I applies to all ship types; oil tankers of 150 GT and above also keep Part II (cargo/ballast operations).

## Procedure / How to Complete It

1. Identify the correct operation code among codes A-I (A: ballasting/cleaning of fuel tanks; B: discharge of dirty ballast water; C: collection and disposal of oily residues/sludge; D: non-automatic discharge of bilge water; E: automatic discharge of bilge water; F: condition of the discharge monitoring system; G: accidental or exceptional discharges; H: bunkering of fuel/lubricating oil; I: additional operational procedures).
2. Record the operation immediately after it is completed — never in advance and never with more than a few hours' delay.
3. State date, code/item, quantity (m³), position (for discharges) and every detail required by the IMO format.
4. The officer responsible for the operation signs the individual entry.
5. The Master signs each completed page, taking responsibility for it.
6. Keep the log on board for at least 3 years from the last entry, available for inspection at any time.

### Diagramma: flusso di registrazione

## Practical Example

Example of a code H — Bunkering entry:

Date | Code | Item | Entry (summary)
--- | --- | --- | ---
14.07.2026 | H | H1 | HFO bunker received: 380.5 m³ at Genoa, from barge "MT Esempio". BDN attached. Signed by 2nd Engineer.
14.07.2026 | C | C2 | Sludge transfer from purifier to sludge tank: 0.8 m³. Signed by 3rd Engineer.

## Real Cases

Numerous cases of detention and fines (some running into the tens of millions of dollars, in well-known USCG cases) have originated from an ORB with missing entries, absent signatures, or bilge volumes inconsistent with tank capacity — often linked to an illegal separator bypass ("magic pipe"). Falsifying the ORB is treated as a criminal offence, not a simple administrative deficiency.

## Common Mistakes Mistake Library

Mistake | Consequence | How to avoid it
--- | --- | ---
Entry not signed by the Master | PSC deficiency, possible detention | Close-out check of each page before the end of the month/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 with a single line, sign the correction, never use correction fluid
Bilge volumes inconsistent with tank capacity/consumption | Investigation into illegal discharges | Periodic reconciliation between estimated production and recorded volumes

## PSC Observations

Missing or unsigned Oil Record Book entries remain among the most frequent MARPOL deficiencies in Paris MOU and Tokyo MOU statistics. The PSCO systematically cross-checks declared volumes against tank soundings and voyage duration: a single error can lead to the ship being detained.

## Operational Tips

- Never leave the ORB «pending»: every operation is recorded the same day.
- Use standardised IMO language (the letter/number codes), not free-text descriptions.
- 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.

## Checklist

- All of this month's entries are signed by the officer responsible for the operation
- The Master has signed every completed page
- No entry is recorded more than 24h late
- Bunker volumes match the Bunker Delivery Note
- No untracked erasure
- The log is available and has been kept for at least 3 years

## FAQ

Who must sign each Oil Record Book entry?
The officer responsible for the operation signs the individual entry; the Master signs every completed page, taking overall responsibility for it.
Is an electronic Oil Record Book allowed?
Yes, provided the electronic format has been approved by the Flag State Administration (or a recognised organisation) in line with IMO guidance.
What happens if a PSCO finds a missing entry?
In most cases a deficiency is raised; if the omission is linked to a suspected illegal discharge, it can lead to detention and a more in-depth investigation.
How long must the ORB be kept on board?
At least 3 years from the last entry, under MARPOL Annex I.
🎬 Additional photos, videos and interactive diagrams for this topic will be available in a future version of the platform.

## Related Topics

Sludge Management Bilge Water Management PSC Knowledge Base (IT)Incinerator Operations

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