We just returned from Rio/Santiago. Heavy seas are not much trouble, if they were why would you be sailing? This is a long cruise with many days at sea which can be boring. Bring books. Also buy a wildlife,flora, natural history guide of below 45th parallel. The ship will provide nothing including the pointing out of various important glaciers, etc. The excursions are overpriced, long and with drivers who cannot speak English. I notice this was question in English - buy and use a small Spanish guide if you want to be on your own a bit. Puerto Madryn has antique buses requiring a gas mask. The observation on taxis was not my observation. We found them everywhere - use radio taxis - price is paid to dispatcher and no money is needed for driver. Take small bills or you will get pesos in change - noone including theship bank will take pesos. We followed a Holland American ship and a Norwegian Line ship. Both had better atmospheres on board and both had more itinerary for the money. No more Celebrity for us.