During unit overhauling of the main engine, sudden rough weather caused an accident in the engine room. State what checks and precautions are taken up prior to carrying out such an operation.

Overhauling a main engine unit (e.g. a cylinder unit - piston, liner, head) is a major, potentially hazardous operation. Prior to starting, the Second Engineer/Chief Engineer must carry out checks and precautions, especially considering the possibility of rough weather and the need to maintain the ship's safety:

1. Risk assessment and permit to work:

• Carry out a risk assessment for the overhaul (lifting, hot work, confined space, heavy loads, moving parts) and issue the appropriate permits (work permit, and if any hot work, a hot-work permit; confined space entry permit if entering the crankcase/space).
• Ensure the work is planned with the Master/Chief Engineer and that the ship's operational status (weather, sea state, traffic) is considered; if rough weather is forecast, postpone or secure the operation.

1. Machinery isolation and safety:

• Stop the main engine and secure it against starting: close the starting air valves, put the turning gear in, lock out the controls, and place a "do not start" tag; isolate the fuel and lubricating oil to the unit.
• Ensure the engine is at a safe condition (cooled, depressurised) and the unit is isolated from the rest of the engine (e.g. the fuel pump, the indicator cocks closed).
• Ensure the turning gear is engaged and the engine is turned to the correct position for the unit being worked on; the engine must not be started while personnel are working.

1. Lifting and rigging:

• Check the lifting gear (chain blocks, slings, eye bolts, the engine room crane) is certified and in good condition; use the correct lifting points and spreader bars; ensure the load path is clear.
• Secure the heavy components (piston, head) so they cannot swing; use tag lines; ensure the crane/hoist is rated for the load.

1. Weather/sea-state precautions:

• If rough weather is expected, secure the work: the engine room crane and the heavy components must be lashed/secured; the work may need to be postponed until the weather moderates.
• Ensure the ship's stability/trim and the engine room are safe; the engine room hatch/doors are secured; the crew are aware of the motion and use safe footing; heavy items are not left suspended.
• Consider the effect of the ship's motion on the lifting and on personnel; use additional lashings and avoid working on the unit during heavy rolling.

1. Housekeeping and access:

• Clear the work area of obstructions, oil and water; provide adequate lighting and ventilation; ensure the escape routes are clear.
• Provide the correct PPE (helmets, gloves, safety shoes, eye protection) and ensure personnel are trained.

1. Emergency preparedness:

• Ensure the emergency arrangements are in place (firefighting, first aid, the emergency alarm) and that the engine room is not left in an unsafe state; if the main engine is out of service, ensure the auxiliary/emergency systems can maintain the ship's essential services (power, steering, bilge, fire) and that the ship can manoeuvre (e.g. use of the emergency/auxiliary propulsion or tugs if needed).
• Inform the bridge of the engine's status and the expected duration; coordinate with the Master.

1. Documentation:

• Record the work in the planned maintenance system, the work permit, and the log; ensure the correct spares and tools are available.

If, despite precautions, rough weather causes an accident (e.g. a component falls, a person is injured, or the engine room is damaged), the emergency organisation is activated: stop work, secure the area, render first aid, raise the alarm, and report to the Master; the incident is investigated and the SMS updated.