A person or device that ballasts; someone who loads or manages ballast in ships; equipment used for ballasting.
From 'ballast' plus the agent suffix '-er' (one who does something). A occupational term for sailors or dock workers responsible for ballast management in maritime commerce.
Medieval ballasters were specialized workers—they had expertise in precisely distributing weight in holds to prevent ships from capsizing, making them crucial unsung heroes of the Age of Exploration.
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