Answer
Safety & Isolation: Isolate all electrical, hydraulic, or pneumatic power supplies to the crane. Cordon off the affected area. Check for any injured personnel or structural damage to the top decks/engine casings.
Formal Reporting: Immediately report the accident as a near-miss/incident to the DPA and the Master. Log it in the Engine Room Logbook.
Managing the Survey & Overhaul:
Inform the incoming Class Surveyor and Superintendent about the incident.
Since the crane is unusable for the planned main engine unit decarbonization/overhaul, postpone the maintenance. Running an overhaul using unapproved, temporary rigging arrangements (like chain blocks attached to non-load-tested structural beams) creates an unacceptable safety risk.
Request Class to inspect the fallen crane structure and issue a Condition of Class / Memorandum for temporary operational restriction until a certified repair and load-testing sequence can be organized.