Insights · Compliance · Sanctions screening
A vessel can be hit by sanctions in two ways: named outright on a list, or reached through the company that owns, operates or manages it. Checking properly means following both routes — and the one fact that ties them together is the IMO number.
A sanctions check on a ship is not a single lookup. A vessel can be designated outright — its name and IMO number written onto a list — or it can be perfectly clean on paper while the company behind it is blocked. Both situations expose anyone who charters, insures, finances, bunkers or buys from that ship. A proper check has to find both, and it has to be built on an identifier that cannot be swapped out, which is why every step below starts from the IMO number.
Four lists do most of the heavy lifting in maritime compliance. They overlap but are not identical, so all four are worth screening:
The reliable way to screen a vessel runs in five steps, in order, because each one depends on the one before it.
Start with the ship's IMO number, not its name. The IMO number is assigned to the hull at construction and never changes through a sale, rename or reflagging. Names and flags are disposable; the IMO number is the only stable key.
Run the IMO number against the vessel records on each of the four lists. Sanctions authorities increasingly publish a ship's IMO number as part of its designation precisely so that a renamed vessel can still be matched. A hit here is a direct designation.
This is the step most checks skip. Use the corporate registry and the GLEIF Legal Entity Identifier to resolve the registered owner, the beneficial owner, the operator and the technical manager — then screen those entities against the same four lists. Under OFAC's 50 Percent Rule and equivalent EU and UK ownership tests, property in which a blocked person holds a controlling or majority interest is itself blocked. A vessel with a perfectly clean hull but a listed owner is still off-limits. See beneficial ownership in shipping for how those layers are unpicked.
Look at the current flag state and, just as importantly, the history of flag changes. A vessel that has reflagged repeatedly, or moved to an obscure or non-cooperating registry, is a classic evasion signal.
Finally, look at how the ship actually moves. Gaps in AIS transmission ("going dark"), spoofed positions, and ship-to-ship (STS) transfers in unusual locations are hallmarks of the so-called shadow fleet moving sanctioned cargo.
The single most common mistake is to screen on the ship's name. A name can be repainted in a port call, and a sanctioned vessel has every incentive to do exactly that, then take a new flag and trade on as if it were a different ship. Search on the name and you lose the trail; search on the IMO number and you do not, because the hull and its history follow that number.
A blocked vessel does not stop being blocked because someone repainted the name on the stern. The designation attaches to the hull — and the hull keeps its IMO number. Principle underlying OFAC, EU, UN and UK vessel designations
Two further considerations widen the net. First, secondary sanctions can penalise non-US parties for significant dealings with certain designated persons, so a European or Asian trader can be exposed even without touching the US financial system. Second, the gatekeepers enforce all of this in practice: banks screen counterparties before releasing funds, and Protection & Indemnity (P&I) clubs — the mutual insurers that cover most of the world fleet — will withdraw cover from a vessel found to be sanctioned, which effectively strands it. A failed check is not an abstract legal risk; it is a frozen payment and a ship that cannot get insured.
Marifest is built around exactly this workflow. Every vessel file is keyed to its IMO number, and the compliance screening matches that number — and the resolved owner and operator — against the OFAC, EU, UN and UK lists across 97,000+ vessels, so a renamed ship ties straight back to its record.
How Marifest helps
Marifest checks each vessel the way a compliance team should — directly by IMO number and indirectly through the company behind the hull — against all four major lists, so a clean name never hides a dirty owner.
Each ship's IMO number is matched against the vessel entries on the OFAC, EU, UN and UK lists, so a designation finds the hull even after a rename.
The registered owner, beneficial owner, operator and manager are resolved via GLEIF and screened in turn — catching a clean ship with a listed parent.
Repeated reflagging and moves to high-risk registries are surfaced on the vessel file as evasion signals worth a closer look.
The result is a single, dated sanctions standing per vessel across all four regimes — auditable and tied to the permanent IMO number.