This consists inter alia of after-breakdown and other occasional inspections.
After every breakdown the Seaworthines certificate has to be renewed. In order to get a new Certificate the yacht has to undergo an inspection and all the inspection findings and after-inspection requirements must be met.
The breakdown includes any hull, rigging, mast damages, any damages to the equipment resulting in the yachts inability to sail or reducing its safety. The breakdown does not include small damages that the crew fixes on its own.
Other occasional inspections are inspections as required by the principal.
For more information on requirements and rules of occasional inspection see “Supervision rules, building and equipment of sea vessels” by PYA Marine Technical Team.