Question 1

You are asked to top up the electrolyte level in a bank of lead-acid batteries in the battery locker. What precautions should you take?

Accepted Answer

Wear appropriate PPE (eye protection and gloves, as the electrolyte is corrosive sulphuric acid), ensure the battery locker is well ventilated (charging batteries can release hydrogen gas, which is flammable and explosive in certain concentrations), avoid any source of sparks or open flame in the space, and use only distilled/deionised water for topping up (not tap water, which introduces impurities that reduce battery performance) Lead-acid batteries present two distinct hazards that are often underestimated by junior crew: the electrolyte itself is a strong acid that causes chemical burns on contact with skin or eyes, and charging batteries produce hydrogen gas, which is both flammable and can form an explosive mixture with air if allowed to accumulate in a poorly ventilated space — battery locker explosions, while uncommon, have occurred where ventilation was inadequate and a spark (e.g. from a tool or a light switch) ignited accumulated hydrogen.

Question 2

You're draining a thermal oil system that was running normally a short time ago. Before opening the drain point, what should you confirm?

Accepted Answer

That the system has cooled and depressurised, and you are positioned clear of the drain point's discharge path On the dredger MV Amazone, two crew members draining a thermal oil system after months of contamination were sprayed with hot oil, suffering severe burns. The investigation found company procedures lacked clear instructions for safe drainage — confirming the system has cooled and depressurised, and standing clear of the discharge path, are essential before opening any drain point on a hot oil system.

Question 3

A thermal oil system has been contaminated and needs draining for cleaning. The written procedure tells you to open the drain valve but doesn't specify a cooling-down period or PPE. What should you do?

Accepted Answer

Treat the gap as a hazard in its own right: apply a suitable cooling/depressurising period and full PPE before proceeding, and raise the procedure gap with the Chief Engineer The FEBIMA investigation into the MV Amazone incident found that although the crew followed company procedures, those procedures lacked clear instructions for safely draining a thermal oil system. A procedure that's silent on cooling time and PPE for a hazardous task is a gap to be closed before the job starts — not a green light to skip those precautions.