Thevelocity in Pacificcircumfluence becoming sloweriscaused by seaicedecrease around theSouth Pole continent and sea ices in Drake Passageplay more importantrole than others.
Bigger ships also tend to pitch and roll less in heavy seas, and they can cross theDrakePassage - which separates South America from Antarctica and can sometimes be very rough - much more quickly.
Expeditions depart from either Puerto Williams in Chile or Ushuaia in Argentina, and include a tough three- to four-day crossing of the notorious DrakePassage.