In this BSafe case study, the chief officer judged the tank was unsafe based on a strong smell at deck level and decided not to test the atmosphere. What was the actual effect of this decision?

A. It correctly kept everyone out of the tank

B. It skipped the one step (confirmed gas testing) that would have formally verified and communicated the actual hazard before ratings were sent to prepare nearby

C. It had no bearing on the subsequent unauthorised entry

D. It was the correct application of the permit to work system

A. Only the Chief Engineer needs to consider this, never the deck watchkeeper

B. None — stability is fixed regardless of loading

C. Increased displacement generally raises the centre of gravity if weight is added high up, and free surface effects in partially-filled tanks can reduce the effective metacentric height (GM)

D. Additional weight always improves stability regardless of where it is placed

A. This only matters when the vessel is at anchor

B. Negligible — watertight doors below the waterline are rarely closed anyway

C. Only relevant if the vessel carries passengers

D. Significant — a failed watertight closure compromises the subdivision the vessel's damage stability calculations rely on, potentially allowing progressive flooding between compartments in the event of damage