Overpitched: Deeper is absolutely correct about it being a Kiowa (B206 B1) and it was most likely the stinger (the bar underneath the tailrotor) which probably went in the water a probably throwing up water into the tailrotor causing the spray. Couldn't be sure without seeing the video though. Hard to say what speed, I only vaguely remember it but I imagine about 60kts would probably be in the ballpark. Doing a stunt like that was not smart - nor a good example to more inexperienced pilots. There is a very good rule in display flying - your show should be as safe as houses whilst giving the illusion to the crowd that it is dangerous! In the UK your display is scrutinised before you are allowed to perform in public - any hint of a dangerous routine and "no show"
