State the difference between flag State control and port State control (PSC). Under which International Conventions Port State Control can be exercised. What do you understand by Memorandum of Understanding in respect of PSC? Name the different MOUs.

Flag State control vs Port State control:

• Flag State control: the control exercised by the State whose flag the ship flies (the flag State) over its own ships. It is the primary responsibility: the flag State ensures its ships comply with the international conventions (SOLAS, MARPOL, STCW, Load Line, MLC, ISM, ISPS) by issuing certificates, carrying out surveys, and enforcing its national law. It has jurisdiction over the ship wherever it is, and is responsible for the ship's compliance, manning, certification and the enforcement of the conventions.
• Port State control: the control exercised by the authorities of a port State over foreign ships visiting its ports, to verify that they comply with the international conventions. It is a secondary/backstop control: the port State inspects foreign ships (regardless of flag) to ensure they meet the standards, and can detain a sub-standard ship or require deficiencies to be rectified. It is based on the right of the port State to inspect ships in its ports and the "no more favourable treatment" principle.

Under which conventions PSC can be exercised: Port State control is exercised under the international conventions that give the port State the right to inspect foreign ships, including: SOLAS 1974 (as amended), MARPOL 73/78 (all annexes), the International Convention on Load Lines 1966, STCW 1978, the International Convention on Tonnage Measurement 1969, COLREGS 1972, the ILO/MLC 2006, the ISM Code, the ISPS Code (SOLAS XI-2), the BWM Convention, the AFS Convention, and the ILO Convention No. 147 (Merchant Shipping (Minimum Standards)). The port State may also inspect under the regional MOUs.

Memorandum of Understanding (MoU) in respect of PSC: An MoU is a regional agreement between the maritime authorities of a group of States to cooperate in the harmonised and coordinated exercise of port State control. It sets out the common inspection procedures, the percentage of ships to be inspected, the targeting/risk-based selection, the exchange of information (a central database), the treatment of sub-standard ships, and the "no more favourable treatment" clause. It is not a treaty but a political/administrative agreement; it makes PSC consistent and effective across a region.

Different MOUs:

• Paris MoU (Europe and North Atlantic).
• Tokyo MoU (Asia-Pacific).
• Indian Ocean MoU.
• Caribbean MoU.
• Abuja MoU (West and Central Africa).
• Black Sea MoU.
• Mediterranean MoU.
• Riyadh MoU (Gulf region).
• Viña del Mar Agreement (Latin America).
• The United States Coast Guard (USCG) operates its own PSC regime (not an MoU but a national system).