We had a great tailwind for the sail up the Rio de la Plata to Buenos Aires. The river (Rio de la Plata) is mostly shallow, especially the farther up one gets, and full of shipwrecks that must be avoided (most of which are marked by cardinal buoys). Because the river is shallow, the waves do not get high, but get steeper instead, so we kept the dropboard in and the hatch closed much of the time to keep the occasional breaking wave from splashing inside the boat. On our last night, we ended up spending most of the hours of darkness tacking back and forth, trying to keep the boat in place, rather than let the tidal current carry us further up the river. This was done to delay our entrance to Buenos Aires until daylight.