Safety experts raised questions about the grandfathering of a crucial stability requirement for ro-ros after new revelations in the investigation into the deadly 2015 sinking of El Faro.

International safety rules require ships to stay within a certain metacentric height or GM, a key measure of a ship’s stability, when loading cargo. But ro-ros built after 2009 amendments to the Safety of Life at Sea (Solas) are held to a somewhat more stringent GM than older ships.