The International Oil Pollution Prevention Certificate, the IOPP Certificate, is the flag-State document that attests a ship has been surveyed and found to comply with MARPOL Annex I. It is required by Regulation 7 of the revised Annex I, adopted by resolution MEPC.117(52) and in force from 1 January 2007, for every oil tanker of 150 gross tonnage and above and every other ship of 400 gross tonnage and above engaged on international voyages to ports under the jurisdiction of other MARPOL Parties. The certificate is issued after an initial survey under Regulation 6, takes the form prescribed in Regulation 9 (Form A for ships other than oil tankers, Form B for oil tankers, both set out in Appendix II of Annex I), carries a maximum validity of five years under Regulation 10, and is kept alive across that period by the annual and intermediate surveys endorsed on it. The IOPP Certificate is the single document a Port State Control officer asks for first at any Annex I inspection, and its absence, expiry, or a mismatch between its Supplement and the ship’s installed equipment is a recognized ground for detention. A practitioner sizing the oil filtering equipment whose installation the certificate records can use the MARPOL Annex I 15 ppm equipment sizing calculator.
What the IOPP Certificate is, and what it is not
The IOPP Certificate is a survey certificate. It records a finding, made on a fixed date by the flag-State Administration or by a classification society acting on its behalf, that the ship’s structure, equipment, fittings, arrangements, and material condition meet the construction and equipment requirements of Annex I. It is not an operational permit, and it does not by itself prove the ship is operating in compliance. A ship can hold a valid IOPP Certificate and still discharge oil unlawfully; the certificate attests the means of compliance exist on board, while the Oil Record Book attests how those means were actually used.
This distinction governs how the certificate is read. A surveyor at a renewal survey confirms that the oil filtering equipment is installed, type-approved, and functioning, that the oil residue (sludge) tanks have the required capacity and arrangements, and on a tanker that the segregated ballast tanks, crude oil washing system, and double-hull cargo-tank protection conform to the rules in force for that ship. The certificate’s Supplement records each of those findings as a tick against a numbered item. A Port State Control officer then checks the ship against the Supplement: the certificate says a 15 ppm bilge separator is fitted, so the officer expects to find one, expects it to work, and expects the discharge to read under 15 ppm.
The certificate is issued against the version of Annex I that applies to the ship by build date and tonnage. A 1990-built product tanker is surveyed against a different set of construction rules than a 2015-built one, because the phase-in regulations for double hulls and protective location apply by keel-laying date. The IOPP Certificate does not freeze the ship at its build standard for all time: amendments to Annex I that apply retroactively, such as the oil-fuel-tank protection rule for ships above 600 cubic meters of fuel capacity, bring the ship into a new requirement at the next survey, and the Supplement is re-endorsed to reflect it. The Supplement also records the monitoring and control equipment a ship needs to operate inside a MARPOL Annex I Special Area, where the discharge limits tighten beyond the general regime.
Applicability: the 150 GT and 400 GT thresholds
Regulation 7.1 sets two carriage thresholds, and they are not the same. Every oil tanker of 150 gross tonnage and above must hold the certificate, and every other ship of 400 gross tonnage and above must hold it, where the ship is engaged on voyages to ports or offshore terminals under the jurisdiction of other MARPOL Parties. The 150 GT tanker limb and the 400 GT general limb match the thresholds that trigger the Oil Record Book (Part II at 150 GT for tankers, Part I at 400 GT for all ships) and the SOPEP carriage duty. The same tonnage gates run through the whole of Annex I’s operational chapter, which is why a surveyor treats the three documents as one package.
The reach is international. The certificate is required for the international voyage, that is, a voyage to a port under the jurisdiction of a Party other than the flag State. A ship trading only within the waters of its own flag State is regulated by that State’s national law, which in practice usually mirrors Annex I but does not require the international certificate. The moment a ship crosses into the jurisdiction of another Party, the IOPP Certificate is the document that other Party’s Port State Control regime is entitled to demand.
Tonnage here is gross tonnage as measured under the 1969 Tonnage Convention, the same figure that drives most of the certificate-threshold rules across the IMO instruments. A ship built before the 1969 Convention applied to it may carry an older tonnage figure, and the flag State resolves which figure governs the IOPP threshold. The distinction matters at the margin: a small coastal tanker measured at 148 GT under one convention and 152 GT under another sits on the wrong side of the 150 GT tanker line in one case and the right side in the other.
Fixed and floating platforms, including drilling rigs and FPSO units when on location and engaged in exploration or exploitation, are dealt with separately under Regulation 39 and are not certificated under the IOPP regime in the same way as a self-propelled trading ship. Warships, naval auxiliaries, and other government ships on non-commercial service are excluded by Article 3(3) of the Convention, though flag States are required to ensure such ships act in a manner consistent with MARPOL so far as reasonable and practicable.
The survey cycle under Regulation 6
Regulation 6 is the engine of the certificate. It sets out five survey types, and the certificate’s validity hangs on completing each of them in its window.
The initial survey comes before the ship is put into service or before the certificate is issued for the first time. It is a complete survey of the structure, equipment, systems, fittings, arrangements, and material that Annex I covers, confirming the ship fully meets the requirements before the IOPP Certificate is first issued under Regulation 7. On a new build this is the survey that turns the construction drawings and the equipment approvals into a certified ship.
The renewal survey is the five-year reset. It is a survey at intervals specified by the Administration but not exceeding five years, and it is as thorough as the initial survey: the whole Annex I scope is re-examined and the certificate is re-issued. Under the Harmonized System of Survey and Certification the renewal survey can be completed within a window ending on the certificate’s expiry date, and the new certificate runs from that expiry rather than from the survey date, so the five-year cycles do not drift.
The annual survey falls within three months before or after each anniversary date of the certificate. It is a general inspection confirming the equipment, associated pump and piping systems, and the oil discharge monitoring and control system have been maintained and remain in a condition matching the certificate. The annual survey is endorsed on the certificate; an annual survey not carried out in its window invalidates the certificate.
The intermediate survey falls within three months before or after the second or third anniversary date, taking the place of one of the annual surveys in the five-year cycle. It is a more searching inspection of the oil filtering equipment, the monitoring and control systems on tankers, the pumping and piping arrangements, and on a tanker the condition of cargo and ballast tanks within the scope of the Enhanced Survey Programme. It too is endorsed on the certificate.
The additional survey, general or partial as the circumstances dictate, is carried out after a repair resulting from a casualty investigation, after any important repair or renewal, or whenever a defect is found that affects the integrity of the ship or the efficiency or completeness of its Annex I equipment. An additional survey ensures the repair or renewal has been effectively carried out, that the material and workmanship are satisfactory, and that the ship still complies.
The harmonized cycle is built so the IOPP Certificate, the SOPEP, the cargo-ship safety certificates, and the other statutory certificates fall due on the same anniversary, letting one attending surveyor close out the whole survey suite in a single attendance rather than calling the ship in four times a year.
The survey windows are not soft targets. The annual and intermediate surveys carry a three-month window on either side of the anniversary, and the renewal survey can be brought forward but not delayed past the five-year expiry. A surveyor who attends late in the window has less room to deal with deficiencies before the window closes, so most managers plan the attendance early in the three-month band. The practical scheduling problem is that a ship trading a fixed liner route may not be in a port with a surveyor when its window opens, which is why the survey is increasingly carried out at the load or discharge terminal by a class surveyor who flies to the ship rather than the ship diverting to the survey. The certificate’s validity hangs on the surveyor reaching the ship inside the band; a missed band is a lapsed survey and an invalid certificate, with no discretion to backdate.
The flag State sets the precise survey scope within the Regulation 6 framework, and the HSSC survey guidelines fill in the detail. A flag State may require more than the minimum, for example an internal examination of a tank the guidelines would let pass on an external survey, where the ship’s age or history warrants it. The surveyor’s report, not the certificate face, records what was actually examined, and that report is the document a casualty investigation or a subsequent surveyor reads to understand the ship’s survey history.
Regulation 7: who issues the certificate
Regulation 7 provides that the IOPP Certificate is issued, after an initial or renewal survey, by the Administration, that is, the government of the flag State, or by any persons or organizations duly authorized by it. In every case the Administration assumes full responsibility for the certificate.
In practice the flag State delegates the survey and the issue to a Recognized Organization, almost always a classification society holding a written authorization from that flag State. The major societies of the International Association of Classification Societies hold these authorizations from most of the open registries and many of the national flags, so the surveyor who attends a Liberia, Marshall Islands, Panama, or Singapore-flag ship is in most cases a class surveyor acting under a delegation agreement. The certificate then carries the flag-State coat of arms and is signed by the Recognized Organization under the authority of the named Administration. The flag State retains the responsibility and the liability; the delegation is of the work, not of the duty.
The Administration’s authorization to a Recognized Organization is governed by the RO Code, made mandatory under Annex I through the relevant amendments, which sets the minimum standards a society must meet and the oversight the flag State must keep. A flag State that delegates statutory survey work without effective oversight is itself open to challenge through the IMO member-State audit scheme. This is the formal answer to the question of how a private classification society comes to issue a government certificate: it does so under a delegation that the government remains answerable for.
Regulation 8: certificates issued by another government
Regulation 8 lets one Party, at the request of the Administration, survey a ship and, if satisfied the ship complies, issue or authorize the issue of an IOPP Certificate to that ship. This is the mechanism that lets a ship be surveyed and certificated in a convenient port by a willing Party even when the flag State has no surveyor and no Recognized Organization in reach.
A copy of the certificate and a copy of the survey report are transmitted as soon as possible to the requesting Administration. A certificate so issued carries a statement that it has been issued at the request of the flag State, and it has the same force and receives the same recognition as a certificate issued by the flag State itself. The regulation also bars the issue of an IOPP Certificate to a ship entitled to fly the flag of a non-Party. The effect is to keep the certificate portable: a ship does not have to return to its flag State to be certificated, but a non-Party flag cannot buy into the recognition system.
Regulation 9: the form of the certificate, Form A and Form B
Regulation 9 fixes the form. The IOPP Certificate is drawn up in the form corresponding to the model in Appendix II to Annex I, in the official language of the issuing country, with a translation into English, French, or Spanish where the official language is none of those.
Appendix II carries two models. Form A is the certificate for ships other than oil tankers. Form B is the certificate for oil tankers. A combination carrier holds the form matching its certificated service. The two forms differ because a tanker must record its cargo-side Annex I systems (segregated ballast, crude oil washing, the cargo monitoring and control system, the slop-tank arrangements) while a non-tanker records only the machinery-space oil-pollution-prevention equipment.
Each form is short: it identifies the ship, names the Administration, records the surveys completed and the date of the initial or renewal survey, and states the date of expiry. The substance of what was found is carried not on the certificate face but on its Supplement, the Record of Construction and Equipment, which is bound to the certificate and is as much a part of it as the face sheet. A certificate face with no Supplement, or a Supplement that has come adrift from its certificate, is treated by Port State Control as an incomplete document.
The Supplement: the Record of Construction and Equipment
The Supplement is where the certificate’s detail lives. There are two Supplements matching the two certificate forms: Form A is supplemented by the Record of Construction and Equipment for Ships Other Than Oil Tankers, and Form B by the Record of Construction and Equipment for Oil Tankers. Both are model forms in Appendix II.
The Form A Supplement records the machinery-space oil-pollution-prevention fit. It states whether the ship is fitted with oil filtering equipment producing effluent below 15 ppm, whether it carries an alarm and automatic stopping device for discharge above 15 ppm, the capacity of the sludge tanks, the standard discharge connection for landing residues ashore, and the means of retention and disposal of oily residues. The surveyor ticks each item against the installed equipment and signs the Supplement.
The Form B Supplement records all of that and then the tanker-specific systems. It states the type of tanker, the deadweight and cargo-tank arrangement, whether the ship is fitted with segregated ballast tanks and how those tanks are protectively located, whether a crude oil washing system is fitted and approved, the construction standard for double-hull or equivalent cargo-tank protection, the inert gas system fit, the slop-tank arrangements and their capacity, the oil discharge monitoring and control system and its type approval, the oil-water interface detector, and the pumping, piping, and discharge arrangements. The Supplement is the inventory against which the rest of Annex I is checked: every other regulation the certificate ties together appears as a line on this record.
The Supplement is also the document a Port State Control officer reads alongside the ship. If the Supplement records a 15 ppm bilge alarm with automatic stopping, the officer expects the alarm to function and the automatic stop to operate on test. If the Supplement records crude oil washing, the officer expects the COW manual on board and the system in working order. A discrepancy between the Supplement and the installed reality, an item ticked on the record but missing or inoperative on the ship, is one of the more serious findings an inspection produces, because it goes to the truthfulness of the certificate itself.
Regulation 10: five-year validity and the HSSC
Regulation 10 governs duration and validity. An IOPP Certificate is issued for a period specified by the Administration not exceeding five years. The five-year ceiling is the hard limit; the certificate cannot be issued or extended beyond it except in the narrow circumstances the regulation allows.
The validity is managed through the Harmonized System of Survey and Certification, the cross-instrument scheme that aligns the survey and certificate cycles of MARPOL, SOLAS, the Load Line Convention, and the relevant Codes onto one set of anniversary dates. The current survey guidelines under the HSSC are maintained by IMO Assembly resolution and are reviewed every two years; the guidelines describe in detail what each survey examines. Under the HSSC, a renewal survey completed within three months before the expiry date lets the new certificate run from the expiry of the existing one for up to five years; a renewal survey completed more than three months before expiry runs from the completion of the survey for up to five years.
Regulation 10 allows limited extensions. Where a renewal survey is completed and a new certificate cannot be issued or placed on board before the expiry date, the Administration or a Recognized Organization may endorse the existing certificate, and it is accepted as valid for a further period not exceeding five months. Where the ship is not in a port in which it is to be surveyed when the certificate expires, the Administration may extend the certificate, but only to allow the ship to complete its voyage to the port of survey, and only where it is proper and reasonable, and for no more than three months; the ship is then not entitled on arrival to leave that port without a new certificate. A certificate issued for less than five years may be extended to the five-year maximum. Short-voyage extensions and renewal-window rules are the routine of certificate management, but the five-year wall stands.
A certificate ceases to be valid before its stated expiry in defined cases: if the annual or intermediate surveys are not completed within the windows Regulation 6 sets; if the certificate is not endorsed in accordance with Regulation 6; and on transfer of the ship to the flag of another State. On a flag transfer a new certificate is issued only after the new flag State is satisfied the ship complies, drawing on the survey history and the certificate held under the previous flag.
The Enhanced Survey Programme for tankers
For oil tankers the survey behind the IOPP Certificate is reinforced by the Enhanced Survey Programme, the ESP, made mandatory through Regulation 6 of Annex I read with the ESP Code adopted by IMO Assembly resolution. The ESP is the structural-survey regime: it prescribes, for oil tankers and bulk carriers, the close-up surveys, thickness measurements, and tank testing that an aging hull must undergo, scaled to the ship’s age.
The ESP scales the survey effort by hull age. A tanker under five years old gets a relatively light structural survey. Between five and ten years, between ten and fifteen, and beyond fifteen, the close-up survey extent, the number of cargo and ballast tanks that must be internally examined, and the density of thickness-gauging readings all increase. The intermediate survey on an older tanker pulls forward a portion of the next renewal survey’s structural scope. The ESP report file, the thickness-measurement records, and the survey-planning document are kept on board and are part of what a surveyor and a Port State Control officer review. The link to the IOPP Certificate is direct: a tanker whose ESP structural surveys are not completed and credited cannot have its IOPP renewal or intermediate survey closed out, so the certificate cannot stand. Class-rule survey intervals and the structural-survey machinery are addressed in the broader continuous survey of hull and machinery regime.
The Condition Assessment Scheme
The Condition Assessment Scheme, the CAS, is a separate but related requirement that applies to certain single-hull oil tankers. It was introduced as part of the accelerated phase-out of single-hull tankers under Regulation 20 (and the carriage restriction in Regulation 21) of the revised Annex I, after the Erika and Prestige losses pushed the IMO to bring forward the end of single-hull operation.
The CAS does not replace the ESP; it adds a verification layer on top of it. For the single-hull tankers still permitted to trade up to their final phase-out date, the CAS requires an enhanced and independently verified assessment of the hull’s structural condition, with a Statement of Compliance issued by the flag State and a CAS Final Report reviewed by the Administration. A tanker subject to CAS that cannot obtain or renew its Statement of Compliance loses its entitlement to trade, and the IOPP Certificate’s continued validity is bound up with that entitlement. With the single-hull fleet now almost entirely retired, the CAS is of narrowing practical reach, but it remains the mechanism that linked structural condition to the right to carry persistent oil during the phase-out years.
How the IOPP Certificate ties the rest of Annex I together
The IOPP Certificate is the knot that gathers the construction and equipment regulations of Annex I into one verified statement. Each substantive regulation appears on the certificate’s Supplement as an item the surveyor confirms, and the certificate’s validity depends on every one of those items continuing to hold.
The machinery-space chain runs through the Supplement’s general section. Regulation 14 requires the 15 ppm oil filtering equipment whose installation and type approval the Supplement records; the surveyor confirms the equipment, the alarm, and the automatic stopping device, and the 15 ppm discharge equipment sizing calculator reflects the capacity the installed unit must meet. Regulation 12 sets the sludge-tank capacity the Supplement states. Regulation 12A brings the fuel-tank protection requirement onto the Supplement for ships above the fuel-capacity threshold. Regulation 15 sets the discharge criteria the monitoring and control system enforces, and the system’s type approval is a Supplement line.
The tanker chain runs through the Form B Supplement’s cargo section. Regulation 18 sets the segregated-ballast and protective-location requirements the Supplement records. Regulation 33 requires the crude oil washing system the Supplement confirms, with its operations and equipment manual. Regulation 19 sets the double-hull construction standard the Supplement states by build date. The cargo monitoring and control system, the oil-water interface detector, and the slop-tank arrangements all appear as confirmed items. A surveyor closing a renewal survey on a tanker is, in effect, re-confirming every one of these regulations in turn and re-endorsing the certificate to say so.
The operational documents sit alongside the certificate rather than on its Supplement, but the survey checks them. The Oil Record Book is reviewed against the equipment the certificate records, and the SOPEP is confirmed current as a survey item. The certificate is the construction-and-equipment half of Annex I compliance; the record book and the emergency plan are the operational half, and a surveyor reads both together.
The certificate within the ship’s statutory suite
The IOPP Certificate is one document in a stack a trading ship must carry, and the HSSC exists precisely so the stack moves together. A typical oil tanker carries, alongside the IOPP, the Cargo Ship Safety Construction Certificate, the Cargo Ship Safety Equipment Certificate, the Cargo Ship Safety Radio Certificate, the International Load Line Certificate, the International Air Pollution Prevention Certificate under MARPOL Annex VI, and on a chemical-capable carrier the certificates under the IBC Code. The harmonized anniversaries let one surveyor’s attendance touch all of them, and the survey-status report a manager keeps is read as a single grid of windows rather than separate clocks.
The IOPP sits next to two MARPOL Annex I documents in particular. The IOPP and the SOPEP are both Annex I requirements and both confirmed at the IOPP survey, but the SOPEP is an approved plan rather than a certificate, and its currency is a survey item rather than a certificate in its own right. The IOPP and the Oil Record Book are the certificate-and-log pair: the certificate says the equipment exists, the record book says how it was run. A Port State Control officer who finds a clean IOPP, a current SOPEP, and a consistent Oil Record Book reads the three as a coherent Annex I package; a discrepancy between any two of them is the thread the officer pulls.
For a combination carrier, an oil-bulk-ore ship that can load oil cargo on one leg and dry bulk on another, the certificate question is which service the ship is certificated for. A combination carrier certificated to carry oil holds the Form B certificate and the tanker Supplement, with the cargo-side systems the Supplement records held in working order even when the ship is on a dry-bulk leg. The surveyor confirms the tanker systems regardless of the cargo the ship happens to be carrying at the survey, because the certificate attests the ship’s capability over the whole period, not its state on the survey day.
Withdrawal and loss of the certificate
A certificate that no longer reflects a compliant ship is withdrawn or ceases to be valid. The cases in Regulation 10 are the routine triggers: a missed annual or intermediate survey, a survey window allowed to lapse, or a flag transfer. Beyond those, the Administration withdraws the certificate where a survey reveals the ship no longer meets the Annex I requirements and the deficiency is not put right.
Withdrawal is not always a formal act on paper. A certificate whose annual survey window has closed without the survey being completed is, by operation of Regulation 10, no longer valid, even though the physical certificate still shows a future expiry date. A surveyor or Port State Control officer reads the endorsement record, not just the expiry date: an expiry date two years away means nothing if the last anniversary’s annual-survey endorsement is missing. This is the most common way a certificate is found dead while still physically in date.
On withdrawal or expiry the ship is, in principle, not entitled to engage in international voyages until a new certificate is issued. In practice the ship is brought to a port, surveyed, and re-certificated, with the short-voyage extension in Regulation 10 used where the ship must reach the survey port. A ship that proceeds to sea on an invalid certificate exposes itself, its owner, and its master to detention at the next port and to enforcement under the coastal State’s domestic pollution law.
Port State Control and the IOPP as a detainable item
The IOPP Certificate is the first document a Port State Control officer asks to see at an Annex I inspection. Port State Control under the regional Memoranda of Understanding, the Paris MoU and the Tokyo MoU chief among them, operates on the IMO Procedures for Port State Control, and those procedures treat the certificate as the entry point into the inspection.
The certificate failures that ground a detention are well defined. The absence of a valid IOPP Certificate is a clear detainable deficiency. An expired certificate, or a certificate invalid because an annual or intermediate survey window has lapsed, is detainable. A Supplement that does not match the ship, an item recorded as fitted but found missing or inoperative, is detainable because it impeaches the certificate. The clearest single example is the 15 ppm bilge separator: the Supplement records it, the officer tests it, and a separator that cannot produce effluent under 15 ppm or whose alarm and automatic stop do not function is both an equipment deficiency under Regulation 14 and a contradiction of the certificate.
Port State Control records the deficiency under a coded scheme: the Paris MoU action codes mark the deficiency as a ground for detention, for rectification before departure, or for rectification within a set period. A detention on an IOPP-related ground holds the ship in port until the deficiency is rectified and, where the certificate’s validity is in question, until the flag State or its Recognized Organization re-attends. A ship detained for IOPP deficiencies also accrues a Port State Control history that feeds the targeting algorithms, raising its risk profile and the frequency of future inspections. The certificate is therefore not a one-time gate at issue; it is a document the ship has to be able to defend at every port, against a Supplement the officer reads line by line.
US Coast Guard practice under 33 CFR Part 151
The United States is a Party to MARPOL and implements Annex I through the Act to Prevent Pollution from Ships and its regulations at 33 CFR Part 151. A foreign-flag ship calling at a US port presents its IOPP Certificate to the US Coast Guard exactly as it would to any Port State Control authority, and the Coast Guard inspects against the certificate and its Supplement.
US Coast Guard practice issues the IOPP Certificate and its Supplement to US-flag ships on the Coast Guard’s own forms, with Form A on the CG-5352A and Form B on the CG-5352B, the Records of Construction and Equipment matching the Annex I Appendix II models. For foreign ships the Coast Guard examines the flag State’s certificate. The federal scheme overlays criminal and civil enforcement on the certificate regime: a ship found to have falsified the records the certificate’s survey relies on, or to be operating equipment the certificate records as compliant in a non-compliant way, faces enforcement that runs well beyond the detention a regional MoU imposes. The certificate, in the US system, is the baseline document, and the enforcement weight sits on the operational records behind it.
Limitations and practitioner notes
The IOPP Certificate attests a condition found on a survey date, not a continuing state. A certificate issued the week before a piece of equipment fails is valid on its face and useless in fact, which is why the annual and intermediate endorsements matter as much as the issue date. A practitioner reading a certificate reads the endorsement record first: a future expiry date with a missing anniversary endorsement is a dead certificate wearing a live one’s clothes.
The certificate does not certify operational compliance, and treating it as a clean bill of operational health is a common error. The Supplement says a 15 ppm separator is fitted; it does not say the crew used it rather than a bypass. The split between the construction-and-equipment certificate and the operational Oil Record Book is deliberate, and the two must be read together. A ship can pass an IOPP survey and still be prosecuted for unlawful discharge; the certificate is no defense to a discharge offense.
The Supplement is the document most often allowed to fall out of date with the ship. Equipment is replaced, a separator is upgraded, a monitoring system is swapped for a different type approval, and the Supplement is not re-endorsed to match. The mismatch is invisible until a Port State Control officer compares the record to the machinery space. Where a retroactive amendment brings the ship into a new requirement, the oil-fuel-tank protection rule is the standing example, the Supplement must be re-endorsed at the next survey, and a Supplement that still reflects the pre-amendment state is a finding.
The delegation to a Recognized Organization does not move the responsibility off the flag State, and a practitioner should not read a class-issued certificate as a class document. The certificate is the flag State’s, issued under the flag State’s authority and the flag State’s liability; the society is its agent. Where a flag State’s oversight of its Recognized Organizations is weak, the certificates it issues carry a higher Port State Control targeting weight regardless of which society did the survey. The certificate’s credibility is, in the end, the flag State’s credibility.
The CAS regime is now of narrow reach. With the single-hull tanker fleet substantially retired under the Regulation 20 and 21 phase-out, the Condition Assessment Scheme governs a shrinking population of ships, and a practitioner is more likely to meet the ESP structural-survey requirements than a live CAS Statement of Compliance. Treating CAS as a general tanker requirement, rather than the single-hull-specific layer it is, misstates the regime.
See also
- MARPOL Annex I oil pollution prevention
- MARPOL Annex I Regulation 14: oil filtering equipment
- MARPOL Annex I Regulation 17: Oil Record Book
- MARPOL Annex I Regulation 18: segregated ballast tanks
- MARPOL Annex I Regulation 19: double hull
- MARPOL Annex I Regulation 33: crude oil washing
- MARPOL Annex I Regulation 37: SOPEP
- Classification society
- Port State Control
- Continuous survey of hull and machinery
- Paris MoU
- MARPOL Convention
- MARPOL Annex I 15 ppm equipment sizing calculator
Related calculators
- MARPOL Annex I/14 - Oil filtering equipment
- MARPOL Annex I 15 ppm equipment sizing
- MARPOL Annex I/15 - Oil discharge criteria
- MARPOL Annex I/17 - Oil Record Book Part I
- MARPOL Annex I/18 - Segregated ballast tanks
- MARPOL Annex I/19 - Double hull
- MARPOL Annex I/33 - Crude oil washing
- IACS UR Z10 survey intervals