Answer
Under MARPOL Annex VI and the latest IMO guidelines (MSC-MEPC.2/Circ.18), responsibility for fuel oil sampling depends entirely on the type of MARPOL sample being drawn.
1. MARPOL Delivered Sample (Bunker Sample)
This is the official regulatory compliance sample drawn during bunkering operations to verify compliance with sulfur limits and SOLAS flashpoint requirements.
Who draws it: Under MARPOL Annex VI, Regulation 18.8.1, the Bunker Supplier's Representative is legally responsible for providing and drawing this sample.
Who must witness it: It must be drawn in the presence of both the Supplier’s Representative and the Ship’s Representative (typically the Chief Engineer, Second Engineer, or designated Bunker Officer).
Where: Drawn continuously throughout the bunkering process at the receiving ship’s inlet bunker manifold using an approved continuous-drip sampler. Both parties must sign the label and log the seal numbers on the Bunker Delivery Note (BDN).
2. MARPOL In-Use Sample
This represents the fuel oil actually flowing to the ship's combustion machinery (main engine, auxiliary engines, boilers, etc.) at any given time.
Who takes it: Port State Control (PSC) Officers or Flag State Administration Inspectors.
Who assists: The Ship’s Crew (under the direction of the Chief Engineer/Engine Officers) physically operates the designated sampling valve to draw the fuel safely, as they are familiar with the system pressure and temperatures.
Where: Drawn from the mandatory, designated In-Use Sampling Points (fitted/designated under Regulation 14.10–14.13) downstream of the in-use fuel oil service tank.
3. MARPOL Onboard Sample
This represents fuel oil that is stored in the ship's fuel tanks and is intended to be used or carried for use on board.
Who takes it: Port State Control (PSC) Officers or Flag State Inspectors.
Who assists: The Ship's Crew or a Specialist Service Provider hired by the authorities.
Where: Taken directly from the fuel storage, settling, or transfer tanks (e.g., via sounding pipes or the transfer pump recirculation system) in line with MEPC.1/Circ.889 guidelines.