Right now most sailors limit their outgoing activities to daytime. Most think it is too dangerous to cross the river in a dinghy at night. The marinas are all managed by people from the first world. Most of them came years ago to the Rio Dulce and the name of the marina is most of the time linked to the person that started the marina. There is little interaction with the local population.
Days can go by without hearing any Spanish.
Those two groups, the sailors and the locals, tolerate the exsistance of each other but rarely mix. A situation I didn't like too much.