lifting keel

Machine-translated from the Swedish article

A drop keel (sänkköl) is a keel on a sailboat that is lowered and raised vertically into a watertight keel case in the vessel's hull. Unlike a centreboard or other centre boards, the drop keel's main function, besides counteracting leeway, is to also give the boat stability by giving the keel's ballast a lower centre of gravity. A variant of the swing keel, which is also movable around its vertical axis.