I only worked seven years on FPSOs assisting the OIM with the maintenance, repairs and inspections of the hull, 100’s of cargo tanks and pump rooms and what to with all cracks found. Why do you suggest I don’t know anything about FPSOs? It is not a ship or tanker when moored and receiving oil. It may be a ship when being towed to location, but on location handling oil it is not a ship/tanker requiring a Master.
Anyway, all staff on an FPSO knows exactly the organization and safety aboard. But I agree! To access a cargo tank may be difficult as an FPSO is never gas free. I. explain about it at my website but I cannot link to it as it is considered as SPAM by the moderators. But it is just basic SAFETY. When I started working in the offshore industry handling hydrocarbon oils at sea, I found that the basic system to inert the cargo tanks was unsafe. The responsible parties had just copied the system used on normal seagoing oil tankers to be used on FPSOs not realizing that the two units are different. You find my paper about on the Internet using Google and “FPSO Inert Gas System”.