doesnt look like it would do much if water rushed over the hood.
For water that steadily drops a bow wake seems to work fine for water over hood deepth for short periods of time (as long as you keep moving).
the problem ive encountered is when you drop off into deep water quick. everything gets really wet really quick! unless the snorkel is up high.
On the Fuel injected rigs if you get stuck in the water as deep as your factory air box and dont get out fast your kinda S.O.L. since the computer isnt very sealed and its hard to keep all water out of a rig if you have to do any recovery.
in this picture water was just above my pedals but just below my computer to say the least i was a little uneasy.