Not “just in case” if the plane was deliberately set down in the assigned spot. The pilot was also, I believe, a glider pilot and could be relied on to accomplish this water set-down relatively safely.
“The pilot was also, I believe, a glider pilot and could be relied on to accomplish this water set-down relatively safely.”
If it was an intentional ditching, a competent pilot wouldn’t have chosen a fixed gear plane to do that with. There’s no way to be sure that you could make a water landing safely without flipping over in a plane like that.