People conflate oil rig work and maritime work constantly. The confusion is understandable. Both involve working offshore, sometimes on the same physical structure. The careers behind them are built on completely different foundations.
The Maritime Side
Jackup drilling rigs move between locations. During transit a jackup is legally a vessel and needs maritime crew to operate it. The marine complement typically includes a marine superintendent, crane operators and sometimes a full bridge team for the passage. When the rig arrives on location and the legs go down, the maritime operation pauses. When it moves again, it resumes.
Semi-submersible rigs and drillships are vessels under maritime law regardless of whether they are in transit or on location drilling. They carry a marine crew running alongside the drilling crew throughout. The master holds STCW certification. The chief engineer manages the vessel’s machinery systems. DP officers keep the rig precisely positioned over the wellhead. These are maritime roles. The certificates, the employment route and the regulatory framework are the same as conventional shipping.
The Offshore Worker Side
Now the other group. Drilling crews, production operators, maintenance technicians. They work offshore. They live offshore during their rotations. But they are not seafarers in any regulatory sense.
They travel to work by helicopter. STCW has nothing to do with their qualifications. A roughneck, a driller, a mud engineer, a production technician: these people come from industrial backgrounds and hold industry-specific certifications that have no connection to the maritime certificate system.
Same geographic location. Completely different career. Same physical structure sometimes. Entirely different regulatory world.
Where the Two Cross
FPSOs are where this gets genuinely complicated. Floating Production Storage and Offloading vessels are legally ships. The master is a maritime officer with STCW certification. The chief engineer runs the vessel’s machinery under maritime regulations. The marine department operates as it would on any other vessel.
On the same hull, in a completely separate hierarchy, sits a production crew running the hydrocarbon processing systems. They report to a production superintendent who answers to a different chain entirely. Their work is oil and gas operations. Their training is oil and gas industry training. Maritime regulations govern the vessel. They are not the ones subject to those regulations.
Who you are on an FPSO is determined by which department you work in and which career you came from. Two people can be on the same vessel, eat in the same canteen, work the same rotation and be operating under entirely different regulatory frameworks with entirely different career histories behind them.
This distinction matters practically when you are deciding which direction to go. Maritime certificates open the marine department door. They do not open the drilling or production doors. Industry-specific offshore certifications open those doors and maritime certificates are not relevant to them.
Know which door you are heading for before you start building qualifications. The preparation is different and starting down the wrong path wastes time that does not come back.