Sets of bills of lading. Bills of lading are requested by shippers in a set usually of three “originals”, although in some Countries many more “original” sets may be required for different reasons, some commercial, some regulatory.
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.
Subject shippers' approval. Like the previous restriction, this is also a "condition precedent" which can cause the fixture to fail to be binding if the shippers do not accept the ship to load the cargo. Again, also like the previous restriction, this can require a third party's approval before a charter between the owner and the charterer becomes binding.
Subject to . . . Many other examples can be cited of the use of "subjects" and both owners and charterers and their middlemen, the shipbrokers, do have considerable imagination to invent and introduce new situations which are meant to influence the enforceability of a time charter or a voyage charter.