In all designs adequate stability, both when on the surface and submerged, can usually be achieved only by the provision of special ballast low down in the ship, usually packed in a strongly constructed ballast keel which facilitates docking and bottoming on the sea bed.
Kulo lonke uyilo uzinzo olwaneleyo xa ingaphezulu kwamanzi nu xa inguphansi, lungafunyanwa khupela xa kunekubakho izinto ezinobunzima obuboelwa obefakwa ezontsi enqanaweni, bupakishane phezu kwesiseko esomeleleyo sikwanzima, ukuze sizokwenza lula ukuma edokisini nokuphuma kwerqanowe.