Uniform System of Buoyage. Buoyage system in which the shape and/or colour of any buoy or beacon has a definite significance. Most maritime nations have a uniform system of their own. International system introduced in 1977.
Union Purchase. Method of rigging cargo derricks so that they need not be moved while loading or discharging a hatch. One derrick plumbs the hatch, the other derrick plumbing the loading or discharging point overside. Runner of each derrick is shackled to the same cargo hook. Precision in plumbing results.