Do you need access to areas protected as nature reserves? My vehicles will be totally neutral to the surrounding environment of the nature reserve. They will not have propeller screws, which, when working, threaten water fauna and flora. Wave propellers work very quietly, so they not harm the creatures living in the water by causing undue stress.
These can be manned electric watercrafts of automated watercrafts supporting research on protected ecosystems. Given the efficiency of these propellers, if equipped with solar cells, they can be energetically self-sufficient. In case of unfavourable weather conditions, they can be powered from batteries