On Board - To be present on or in the ship.
Category: - Maritime

On Deck - To be present on the upper deck; in the open air.
Category: - Maritime

On-Scene Commander - (OSC) The commander of a search and rescue unit designated to co-ordinate search and rescue operations within a specified search area. "commandant sur place"
Category: - SAR

Open Registry - A term used in place of "flag of convenience" or "flag of necessity" to denote registry in a country which offers favorable tax, regulatory, and other incentives to ship owners from other nations.
Category: - Maritime

Optimization - The procedure or procedures used to make a system or design as effective or functional as possible
Category: - Risk

Ordinal - A level of measurement at which only relative information is available about a feature, such as a ranking. For a highway, for example, the line is coded to show a Jeep trail, a dirt road, a paved road, a state highway, or an interstate highway, in ascending rank.
Category: - GIS

Ordinary Seaman - A deck crew member who is subordinate to the Able Bodied Seamen.
Category: - Maritime

Ore-Bulk-Oil Carrier - A large multi-purpose ship designed to carry cargoes wither of ore or other bulk commodities or oil so as to reduce the time the ship would be in ballast if restricted to one type of commodity. This type of ship is sometimes called bulk-oil carrier.
Category: - Maritime

Ore Carrier - A large ship designed to be used for the carnage of ore. Because of the high density of ore, ore carriers have a relatively high centre of gravity to prevent them being still when at sea, that is, rolling heavily with possible stress to the hull.
Category: - Maritime

Ore-Oil Carrier - A ship designed to carry either ore or oil in bulk.
Category: - Maritime