any body of liquid which has an unconfined upper surface, free to remain parallel to the horizontal as the ship rolls and pitches, is said to have a free surface. Free surface has a detrimental effect on the transverse stability of a vessel, and leads to reduction in metacentric height
nawuphi na umzimba wolwelo onomgangatho ophezulu ongalawulwayo, okhululeke ukuba uhlale uthe nkqo ngokulinganayo nenqanawe njengokuba ihamba itshona ivela, kuthiwa inomgangatho okhululekileyo.