Safe Return to Port requirement

The International [Maritime Organization] is helping members comply with the Safe Return to Port requirement in the 2009 International [Safety of Life at Sea treaty].
The requirement was prompted by the increasing size of passenger ships.
The more passengers a vessel has the longer it takes to evacuate.
The requirement defines thresholds, and how long the vessel should remain safe for evacuation. It defines a threshold where a ship's crew should be able to return to port without requiring passengers to evacuate.