ULCC -Ultra Large Crude Carriers. Tankers larger than 300,000 dwt.

UNCTAD -United Nations Conference on Trade and Development

UNMANNED MACHINERY SPACES- A space where alarm bells are installed on the bridge of a ship to trace or rectify any machinery faults. The computerized devices will report any fault immediately it appears and the engineers on board can attend to the necessary ramifications.

UNSEAWORTHINESS - The state or condition of a vessel when it is not in a proper state of maintenance, or if the loading equipment or crew, or in any other respect is not ready to encounter the ordinary perils of sea.

U.S. EFFECTIVE CONTROLLED FLEET- That fleet of merchant ships owned by United States citizens or corporations and registered under flags of "convenience" or "necessity" such as Liberia or Panama. The term is used to emphasize that, while the fleet is not U.,$.-flag, it is effectively under U.S. control by virtue of the ship's owners and can be called to serve U.S. interests in time of emergency.

U.S.-flag vessels- are registered in the United States and are subject to additional U.S. laws and regulations to which foreign-flag vessels are not. They must be owned by U.S. citizens, corporations, or governments and must be crewed mainly by U.S. citizens.