Poor communications were a significant factor in this incident, and situational awareness was lacking in the executive team: no crew member should ever be inside the chain locker when a cable is about to be lowered or dropped.
A chain hook or other wooden device must be used to flake out the cable to prevent it from piling up and stowing in the chain locker, and the crew member attending to this task must leave the locker once it is complete.
There appears to be a design issue with the chain locker: either the locker is too small to accommodate the cable pile when the anchor is stowed, or the spurling pipes are not adequately designed to allow the cable to self-stow. Design modifications should be considered to eliminate this unnecessary risk before the next docking.
Crew training should be provided on anchoring procedures and the risks outlined. The wearing of ear defenders is questionable when clear audible communications for anchoring operations are required, and a clear means of communications must be found.