The open hatch bulk carrier, often referred to as OHBC or conbulker, is a type of cargo ship with direct access to the cargo space by means of shutters that involve the full width of the ship. As a result, large freight units can be lowered to the correct location. If possible, the cargo spaces or shutters are designed to fit around standard dimensions of freight units. Sometimes a portal crane is installed. Extra attention is paid to material to load the freight. These congestors are very expensive because additional steel is needed to widen the shutters. This is crucial to providing strength. The open shutters are useful for wood products such as pre-slung timber and logs. The heavy units are easier to transport than in a conventional bulk carrier. The first open hatch bulk carrier was built in 1962, for the use of paper trade. Source
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