Operational guide · Certification & surveys

IOPP Certificate: the Supplement is the document that matters

The certificate attesting a ship's compliance with MARPOL Annex I: oil tankers of 150 GT and other ships of 400 GT on international voyages, validity not exceeding five years, and the part an inspector actually reads is not the certificate but its Supplement.

IOPPMARPOL Annex Icertificationsupplementoily water separator

Operational Explanation

The International Oil Pollution Prevention Certificate attests that the ship has been surveyed and found to comply with Annex I of MARPOL. The certificate itself says little: name, IMO number, tonnage, survey dates and expiry. Everything an inspection needs sits in the Supplement, which forms an integral part of it and without which the document is incomplete.

The Supplement comes in two forms: Form A for ships other than oil tankers and Form B for oil tankers. It lists, item by item, the equipment actually installed — oily water separator and 15 ppm alarm, automatic stopping device, capacity of the oil residue (sludge) tanks, the discharge monitoring and control system on tankers — and any exemptions granted. It is a statement about the material state of the ship, not a formality: when the equipment changes and the Supplement does not, the document stops describing the ship in front of you.

Regulatory Reference

Annex I of MARPOL, in the revised version adopted by resolution MEPC.117(52) and in force since 1 January 2007. Four provisions govern the certificate:

Regulation 6 — surveys: initial before the ship is put in service, renewal at intervals specified by the Administration and in any case not exceeding five years, intermediate and annual.
Regulation 7 — issue or endorsement of the certificate after survey, by the Administration or by those acting on its behalf.
Regulation 9 — form of the certificate: the model in Appendix II to the Annex, together with the Supplement, Form A or Form B.
Regulation 10 — duration and validity: not exceeding five years. The certificate ceases to be valid if the required surveys are not completed within the periods specified, and when the ship transfers to the flag of another State.

The same thresholds and the same duration are stated in Shipping Guidance Notice 082 of the Gibraltar Administration, which restates them in the same terms.

The windows for annual, intermediate and renewal surveys are not repeated here: they are covered in Harmonized System of Survey and Certification and in Renewal Survey and certificate renewal, and those are the authoritative pages.

Scope of Application

Every oil tanker of 150 gross tonnage and above and every other ship of 400 gross tonnage and above engaged in voyages to ports or offshore terminals under the jurisdiction of other Parties to the Convention. The two thresholds are not interchangeable: a 300 GT cargo ship is outside, a 300 GT oil tanker is inside.

Ships that never leave the waters of their own flag are outside the regime: they are governed by national rules, which may be more or less demanding but are not Annex I.

Procedure / How to Complete It

Open the Supplement, not just the certificate: that is where you read what the ship declares it has on board.
Compare each item with the equipment installed: make, model and type approval number of the separator and the 15 ppm alarm, declared capacity of the oil residue tanks, presence of the automatic stopping device.
After every replacement or modification of the listed equipment, ask the Administration or the recognized organization for the Supplement to be re-endorsed.
Check that all annual and intermediate endorsements are in place: an unendorsed certificate ceases to be valid even if the expiry date is far off.
Keep the type approval certificates for the equipment named in the Supplement together with the certificate: they are what makes the declaration verifiable.

Practical Example

In dry dock the oily water separator is replaced with a unit of a different make, newer and properly approved. The job is done well and nobody touches the Supplement. Three months later, at an inspection, the officer reads the old unit's approval number in Form A and finds a different one in the engine room. It is not an equipment problem: it is a certificate that no longer describes the ship, and it is treated as such.

What Typically Goes Wrong

The failure is almost never a missing certificate: it is the distance between the Supplement and the engine room. The certificate is filed as a closed obligation, the Supplement is not opened again until the next survey, and in the meantime the equipment changes. The second failure is the reverse: the equipment and the Supplement are both updated, but the type approval certificates that support it are not kept on board.

Common Mistakes Mistake Library

Mistake	Consequence	How to avoid it
Equipment replaced without the Supplement being re-endorsed	Deficiency: the certificate does not describe the ship	Put the Supplement re-endorsement in the modification procedure, not in the survey plan
Certificate presented without the Supplement	Incomplete document: the Supplement forms an integral part of the certificate	Keep the two sheets physically together, copies included
Annual endorsement missing while the expiry date is still far off	The certificate ceases to be valid under Regulation 10	Track the endorsements, not just the expiry date

What the PSCO Checks

The Port State Control Officer (PSCO) opens the Supplement and goes down to the engine room holding it: comparing make, model and type approval number of the separator and the 15 ppm alarm, checking the presence and operation of the automatic stopping device where required and, on tankers, the discharge monitoring and control system. They also check that all annual and intermediate endorsements are there and that the declared oil residue tank capacity matches the installation. A Supplement that does not match what is installed almost always opens the Oil Record Book as well.

Operational Tips

Photograph the nameplate of the equipment named in the Supplement and keep it in the same folder: it makes the comparison immediate and shortens the argument.
On handover from a dry dock, ask explicitly which Supplement items were touched: the yard knows, the ship often finds out later.
The Supplement is the first document to read when joining a new ship: it says what the Administration believes is on board.
An exemption noted in the Supplement carries as much weight as an obligation: read it and understand it, do not skip it because it is in small print.

Preparation checklist

Study checklist. This summary is for study and preparation. It does not replace the Company's Safety Management System procedures or the official text of the regulation.

Certificate and Supplement present together, in the same copy
Correct Supplement form: A for ships other than oil tankers, B for oil tankers
Supplement items compared one by one with the equipment installed
Type approval certificates on board for the listed equipment
All annual and intermediate endorsements in place and legible
Oil residue tank capacity consistent with the installation

FAQ

Is the certificate valid without the Supplement?

No. Regulation 9 prescribes the Appendix II model together with the Supplement: without it, the document is incomplete.

Does a 300 GT cargo ship need an IOPP?

No: the threshold for ships other than oil tankers is 400 GT. A 300 GT oil tanker does, because for oil tankers the threshold is 150 GT.

What happens to the certificate if the ship changes flag?

It ceases to be valid. The new Administration issues its own certificate after the relevant checks: the old one does not transfer.

Does replacing a separator with an equivalent one require a new survey?

It requires at least the Supplement to be re-endorsed by the Administration or the recognized organization, because the make, model and approval number listed all change.

IOPP Certificate: the Supplement is the document that matters

Operational Explanation

Regulatory Reference

Scope of Application

Procedure / How to Complete It

Practical Example

What Typically Goes Wrong

Common Mistakes Mistake Library

What the PSCO Checks

Operational Tips

Preparation checklist

FAQ

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