Periodic inspections are required to verify that ships are properly maintained. Surveyors will inspect ships with load line certificates to ensure protections for openings, guard rails, freeing ports, and crew access are effective. They also check that no changes to the hull or superstructure would impact the ship's freeboards. Inspections must occur within 3 months before or after each anniversary of the load line certificate survey, with intervals between inspections of 9 to 15 months. If the ship complies, the surveyor will endorse the load line certificate noting compliance with convention or rules provisions.