Ballast Water Record Book: Entries, Format and PSC Expectations

Updated 2026-06-16

The Ballast Water Record Book is the primary evidence a vessel uses to prove compliant ballast operations under the BWM Convention. It must capture every ballast uptake, treatment, internal transfer, discharge and exchange in a prescribed format. This article covers the required entries, the standardized codes, retention rules and the documentation errors that most often trigger Port State Control deficiencies.

Ballast Water Record Book: Entries, Format and PSC Expectations

Key takeaways

Regulation B-2 requires every affected ship to keep a Ballast Water Record Book in the prescribed IMO format.
Every uptake, treatment/circulation, discharge to sea, discharge to reception facility and exceptional event must be logged.
Entries must be signed by the responsible officer and each page by the master; records are retained two years on board, three years ashore.
Standardized entry codes ensure any inspector can read the book consistently worldwide.
Common PSC deficiencies are missing or unsigned entries, illegibility and inconsistency with the BWM Plan or system logs.
Record BWMS parameters (TRO, UV intensity, flow) and cross-reference alarms to make records defensible.

Legal Basis and Purpose

Regulation B-2 of the BWM Convention requires every affected ship to carry a Ballast Water Record Book, in which all ballast water operations are recorded. It is the operational logbook of the Convention, equivalent in function to the Oil Record Book under MARPOL, and it is the document Port State Control officers reach for first when assessing compliance.

The record book must be available for inspection at all reasonable times and, for a ship without crew under tow, may be kept by the person in charge of the tow. Entries must be made promptly and signed by the officer in charge of the operation, with each completed page signed by the master.

Records of each operation must be retained on board for a minimum of two years after the last entry, and thereafter kept under the company's control for a minimum of three years. This retention chain means even archived records can be requested during audits and investigations.

What Must Be Recorded

Every ballast water operation must be logged: uptake (loading) of ballast, circulation or treatment for ballast water management purposes, discharge of ballast into the sea, discharge to a reception facility, and any accidental or exceptional uptake or discharge. Exchanges under D-1 and treatments under D-2 are both recorded with the relevant operational detail.

Required detail includes the date, ship's position (latitude and longitude), tank or tanks involved, volume, and the temperature and salinity where relevant. For exchange, the percentage exchanged and the method are noted; for treatment, the operation of the BWMS and any bypass should be recorded. When a system is bypassed or fails, the reason and the contingency action taken must be documented.

The Convention provides a standard format with entry codes that group operations logically, so an inspector anywhere in the world can read a record book in a consistent structure. Many operators now keep electronic record books accepted by their flag administration, which reduce transcription errors and improve legibility while still requiring proper authentication.

Standardized Entry Codes

The IMO format organizes entries under letter codes covering categories such as when ballast is taken up, when ballast is circulated or treated, when ballast is discharged to sea, when ballast is discharged to a reception facility, and accidental or other exceptional discharges. Each code prompts the specific data fields needed for that operation.

Consistency matters. Volumes recorded at uptake should reconcile with volumes discharged, allowing for tank soundings and operational realities. Positions should be plausible against the voyage track, and times should be sequential. Inspectors look for internal coherence as much as completeness, because contradictory entries suggest records made after the fact rather than in real time.

Where a BWMS alarm, fault or bypass occurs, the record book entry should reference the event and link to the contingency measures taken and any subsequent treatment. This ties the narrative of the record book to the system's own alarm and treatment logs, creating a defensible, cross-referenced account.

Common Port State Control Deficiencies

The most frequent deficiencies are not exotic. They include missing entries, entries not signed by the responsible officer, pages not signed by the master, illegible handwriting, and gaps where ballast operations clearly occurred but were not logged. A record book that is up to date and internally consistent removes the easiest grounds for a deficiency.

Discrepancies between the record book and the Ballast Water Management Plan, or between the record book and the BWMS treatment logs, are a red flag. If the plan describes a treatment sequence the record book does not reflect, or the system logs show no treatment while the record book claims D-2 compliance, the officer has cause to investigate further and potentially to sample.

Detentions are possible where records suggest the ship has discharged untreated ballast in breach of the standard, or where the record book is absent or grossly deficient. Keeping the book current, signed and consistent with the plan and system logs is the single most cost-effective compliance practice on board.

Best Practice for Audit-Ready Records

Make entries at the time of the operation, not at the end of the watch or voyage. Record the BWMS operating parameters that prove treatment occurred, such as TRO or UV intensity and flow, and cross-reference any alarms. Keep the Ballast Water Management Plan, type approval certificate and commissioning test report filed alongside the record book so the full compliance picture is available in one place.

Train deck and engine officers on the entry codes and on what an inspector will check, and conduct periodic internal verification that record book entries reconcile with system logs and tank soundings. For electronic record books, confirm the system is one the flag administration accepts and that authentication and backup are in place, since loss of records is itself a serious finding.

Frequently asked questions

How long must Ballast Water Record Book entries be kept?

Each entry must be retained on board for at least two years after it is made, and then kept under the company's control for at least three years. This means records can still be requested during later audits or investigations.

Can I keep the record book electronically?

Yes, provided the electronic record book is of a type accepted by the vessel's flag administration. Electronic books reduce transcription errors and improve legibility, but they still require proper authentication, backup and the same content as the paper format.

What happens if the BWMS is bypassed?

Any bypass or system failure must be recorded with the reason and the contingency action taken, such as ballast water exchange or arranging treatment before discharge. The entry should cross-reference the system's alarm logs so the record is consistent and defensible during inspection.

What are the most common record book deficiencies in PSC inspections?

Missing entries, entries not signed by the responsible officer, pages not countersigned by the master, illegibility, and inconsistencies between the record book, the BWM Plan and the system's treatment logs. Keeping the book current and internally consistent prevents most findings.

Sources

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