MEG4 Explained: What It Means for Mooring Rope, and the Road to MEG5

Mooring / Commercial marine / Technical guide

MEG4 gets asked about constantly, and answered precisely less often. Here’s what it actually is, what the MEG4 certificates really contain, whether your rope genuinely needs one, and what’s known so far about a future MEG5.

Facts and figures in this guide are checked against OCIMF’s own publications and independent industry sources — see references below.

What MEG4 actually is

Mooring Equipment Guidelines, Fourth Edition (MEG4) is a publication from OCIMF, the Oil Companies International Marine Forum, setting out recommended minimum requirements for the safe design, performance and operation of mooring systems on tankers and gas carriers at terminals. It’s guidance, not law — OCIMF is an industry forum, not a regulator — but it’s become the reference point nearly every tanker and terminal mooring specification is built around.

MEG has existed since first being published in 1992, with a second edition in 1997, a third edition (MEG3) in 2008, and the current fourth edition (MEG4) issued in July 2018.^[2] Each revision has responded to real incidents and genuine confusion in the previous edition’s terminology — MEG4 in particular was written, in collaboration with the Cordage Institute, Eurocord and the International Association of Classification Societies, to resolve widespread disagreement over exactly what “Minimum Breaking Load” meant in practice, and added a new emphasis on human factors, mooring line and tail retirement criteria, and documentation.^[1]

What MEG4 requires of the rope itself

MEG4 sets out the reference framework nearly every tanker and terminal now specifies against — Ship Design MBL, Line Design Break Force and Tail Design Break Force, and how they relate to one another. We’ve covered the specific figures in detail in our mooring tails guide, so we won’t repeat them here. What’s worth adding is the scope beyond strength figures: MEG4 also introduced clearer guidance on mooring line and tail purchasing, condition-based monitoring and retirement, snap-back zone identification, and a formal Mooring Line Management Plan that ties a vessel’s actual equipment to the guidance rather than leaving it as a paper exercise.

What the MEG4 certificates actually are

This is the part that causes most of the confusion, and “MEG4 certificate” is itself slightly imprecise — OCIMF actually publishes three distinct template documents under MEG4’s Appendix B: a Mooring Line Certificate, a Mooring Tail Certificate, and a Mooring Line Base Design Certificate.^[3] Each is a defined template manufacturers complete to declare a specific line or tail’s construction, design break force, and the test data behind it, in a consistent format regardless of which manufacturer issued it.

That consistency is the entire point. Before MEG4, break load figures from different manufacturers weren’t always calculated or presented the same way — OCIMF has specifically noted confusion among ship owners who incorrectly believed a mooring line’s certificate had to exactly match a requested MBL figure, rather than meet or exceed it.^[2] A properly completed MEG4 certificate should be readable and comparable the same way regardless of supplier — which is also why it isn’t a substitute for the batch-level traceability we cover in our guide to reading a rope test certificate. The two do different jobs: MEG4’s templates standardise what’s declared and how; batch traceability confirms the specific coil you’ve received actually matches it.

One further point worth knowing: OCIMF’s own certificate templates carry an explicit note that completing one does not constitute approval or certification by OCIMF itself.^[4] The certificate confirms the manufacturer’s declared test data follows MEG4’s format — it isn’t OCIMF signing off on the rope.

Does your rope actually need one?

Strictly, MEG4 is scoped to tankers and gas carriers moored at terminals — it was never written as a universal requirement for every vessel type or every rope application. No flag state mandates a MEG4 certificate by law. But the commercial reality is different from the legal one, and it’s worth being clear about why. OCIMF’s Vessel Inspection Questionnaire, now in its seventh edition, includes questions drawn directly from MEG4, and SIRE 2.0’s vessel inspection questionnaire similarly draws on MEG4’s concepts and recommendations.^[2],[5] SIRE feeds the vetting inspections that oil majors and charterers rely on to accept a vessel. In practice, that turns MEG4 compliance from a voluntary guideline into something very close to a condition of trade for tankers — not because any regulator requires it, but because the commercial gatekeepers do.

Outside tanker and gas carrier mooring — a workboat’s mooring lines, a general cargo vessel, a towing arrangement — MEG4 doesn’t formally apply at all, and asking for a “MEG4 certificate” on that kind of rope is a category error, similar in shape to requests we occasionally see for LOLER certification on gear that was never lifting equipment in the first place. The better question in those cases isn’t “does it have a MEG4 certificate” but “what standard was this actually tested to, and can the supplier prove it” — which is exactly the checklist in our certificate guide above.

What about MEG5?

Worth being straightforward here rather than speculative: at the time of writing, OCIMF has not published or announced a draft of a fifth edition. Based purely on historical cadence — first published 1992, second edition 1997, third edition (MEG3) 2008, fourth edition (MEG4) 2018^[2] — gaps between editions have run five, eleven and ten years respectively. That pattern doesn’t point to a fixed cycle, and it’s pattern-matching on past behaviour, not a confirmed timeline. Anyone telling you the specific contents of a MEG5 right now is guessing.

What is reasonable to say is the direction MEG4 already pointed in: greater emphasis on human factors and crew safety, more structured condition-based monitoring rather than fixed replacement intervals, and closer integration with alternative mooring technologies. If a future edition builds further on any of MEG4’s themes, those are the most likely candidates — but they’re informed extrapolation, not an OCIMF announcement, and we’ll treat this section as due an update the moment that changes.

Häufig gestellte Fragen

Is MEG4 a legal requirement?

No — MEG4 is industry guidance published by OCIMF, not law or flag-state regulation. In practice, though, it functions close to a requirement for tanker trade because OCIMF’s own Vessel Inspection Questionnaire draws on it, feeding directly into the SIRE vetting most oil majors and charterers rely on.

What is a MEG4 Mooring Line Certificate?

It’s one of three standard template documents published by OCIMF under MEG4’s Appendix B — alongside a Mooring Tail Certificate and a Mooring Line Base Design Certificate — that manufacturers complete to declare a mooring line’s construction and design break force in a consistent, comparable format. OCIMF notes that completing one does not constitute approval or certification by OCIMF itself.

Does every rope need a MEG4 certificate?

No. MEG4 is scoped specifically to tankers and gas carriers moored at terminals. Rope for other applications — workboats, towing, general cargo mooring — falls outside MEG4’s scope, and should instead be checked against whichever standard genuinely applies, such as ISO 2307 or the relevant Cordage Institute specification.

Is MEG5 coming, and when?

OCIMF has not announced or published a draft of a fifth edition at the time of writing. Gaps between the first four editions have run five, eleven and ten years respectively, which doesn’t point to a fixed cycle — a future edition is plausible on that pattern but entirely unconfirmed, with no specific date or content that should be assumed.

References

1. OCIMF — Mooring Equipment Guidelines, Fourth Edition (MEG4). ocimf.org/publications/books/mooring-equipment-guidelines-meg4
2. SAFETY4SEA — OCIMF Mooring Equipment Guidelines (MEG4) – An Update. safety4sea.com — MEG4 update
3. OCIMF — MEG4 Mooring Line Certificate, MEG4 Mooring Tail Certificate and MEG4 Mooring Line Base Design Certificate templates. ocimf.org — Document Library
4. OCIMF — MEG4 Mooring Tail Certificate template, certification disclaimer. ocimf.org — Mooring Tail Certificate (PDF)
5. Wilhelmsen Ships Service — An Overview of the Regulations and Guidelines Governing Mooring Lines. wilhelmsen.com — MEG4 and mooring guidelines
6. Publication dates for editions one to three cross-checked against Witherbys and Seamanship International publisher records (Studocu reproduction of MEG3 front matter, AbeBooks/Amazon ISBN 9781905331321).

Figures and dates in this guide were checked against multiple independent sources at the time of writing. OCIMF’s own publications are the authoritative source for current MEG4 requirements — always confirm against the current edition and your vessel’s own Mooring System Management Plan before specifying or ordering.