Polish registered commercial yachts are required to be inspected on a 5 year schedule. These requirements apply to both bareboat charter and crewed operations, and for any length of vessel under 24 meters.
Professional examinations are also required after: Grounding accidents, Hull refits, or installation/replacement of electrical systems.
What exactly is a Commercial Yacht under the Polish flag? The Polish Maritime Law definition is :
...commercial yachts are those that are made available for a fee; tourist cruises are organized on them (transporting people), sailing and motorboat training, setting out for fishing or they are chartered (provided without a crew for payment)...
The recognized organizations that can perform surveys so far authorized by the minister responsible for maritime economy are: Polish Ship Register, Russian Maritime Register of Ships, Lloyd'sRegister, RINA, Bureau Veritas, DNV GL, American Bureau of Shipping.