Subject receivers' approval. This is an unusual restriction and can make the charter dependent on the cargo receiver's approval of the ship in the discharging port.
Subject approval of relevant authority. This affects the enforceability of a charter if the ship's certification and cargo handling capabilities are required to meet with official approval. For example, if a vessel is not provided with a valid "document of authorisation" it may not be allowed to load grain and the charter may depend on permission being granted to load.