Re: Boy killed by lightning in our anchorage, what would you do?
Even though it was "fresh" water, it still conducts. And when lightning is about one of the rules is STAY OUT OF WATER because any strike in your area, will spread through the water and that's going to hurt or kill anyone in it.
Opinions about lightning safety vary, but storms rarely just happen.
The most productive thing might be to wait a while, and then hold some lightning safety classes. Including the most basic one: If the sky is gray and the forecast, which you DID listen to, call for storms? GTF off the water. Now, not later.
Some docks also keep a weather radio going all day, at the dockhouse, for the benefit of folks who have showed up without checking the weather. That's not expensive either.