John Halliwell wrote:

In article , Tony
Williams writes
I recall being told, in my target-shooting days, of a range which had
a lake between the firing point and the targets. On a calm day with no
ripples, they found that if they aimed at the reflection of the target
the bullets would ricochet off the water and hit the target. Of
course, the angle was very shallow.

There's a scene in The Dam Busters where the guy playing Barnes Wallis
explains that in Nelson's day the RN gunners used to bounce cannon balls
off the water to improve their effectiveness. No idea if correct or why
though?

To get a hit right at the water line. The solid shot punched a hole only
so big, and a waterline hit was the most effective way to get the
opposition's attention.