Thanks. Well, that advise is pretty obvious and doesn't address the question. There is a problem fling over water in certain situations. That is clear from several posts. I can be incredibly careful at 3 feet over the water but I'm guessing that could be trouble if we're talking a lake with glass smooth water. On the other hand if there is slight wind with ripples, possibly not. So do I just experiment and hope for the best or does someone have an answer to my question, either from experience or from specific knowledge of the sensor function?
Experiment and get back to us with the results.