Originally Posted by EwenT
In Rio Dulce, Guatemala
we can have both at the same time. Generally speaking it is a freshwater river, but we get salt water
ingres depending upon rain fall. I dont recall
the month this happened, but almost certainly in rainy season when we get most rain and lightening. If so there would have been little to no salt water
The salt water
ingress here comes in under the fresh. So, even in dry season, there is a layer of fresh water on top. The salt layer just gets thicker. More saltwater species migrate upstream and deeper dwelling freshwater species often die off in large numbers.
So, in rainy season the boat itself was likely entirely in freshwater.