Grogging is a once common, but now outlawed, practice on ships where the sailors are surgically-altered to effectively restrain them to their ships. The sailor’s chest cavity is hollowed out (some organs being removed or just shifted around a little) and a window and valve installed. The space is filled up with a bright green liquid called grog, which is brewed on the ships. Usually the ship will have its own distinctive ingredients for the grog, on which the sailors become dependent, so that they would die if taken to another ship.
Side-effects of grogging include becoming docile, suggestible, and a slowing of the ageing process.