Bareboat Charter Registration and Dual Flagging
How a ship flies a second flag for the charter period: suspension of the underlying registry, MLM 1993 Article 16, and the UNCLOS one-flag rule that permits it.
Bareboat charter registration is the mechanism by which a ship flies the flag of the bareboat charterer’s chosen State for the duration of a bareboat charter party , while title and the registered mortgages stay on the underlying register. The underlying registry suspends the ship’s right to fly its flag; the bareboat registry grants that right and takes over the flag-State functions for the charter period.
The structure is lawful because the ship sails under one flag at any moment, which is what UNCLOS Article 92(1) requires. A ship genuinely flying two flags at once falls under Article 92(2) and may be assimilated to a ship without nationality. The only operative multilateral rule on the point is Article 16 of the International Convention on Maritime Liens and Mortgages, 1993, which requires cross-reference entries in both registers and the written consent of every registered mortgagee before a temporary transfer, and which confirms that no State is obliged to permit the arrangement in either direction.
The full article will cover the registry-by-registry position, the certificate set that is reissued on entry and on closure, the consents the underlying registry and the mortgagee require, the treatment of tonnage, call sign and MMSI, and the interaction with flag State jurisdiction and port State control.