Some dinghy sailboats have a hole in the bottom of their deck used to automatically bail out water after a capsize.
The mechanism only works if the boat is moving. The faster it sails, the faster water is drained out of the cockpit, by suction.
Then. Is this an example of the "venturi effect"?
If so, then: why? According to wikipedia
The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of pipe
(as the fluid gains speed).
- there is no constricted section of pipe on the sea behind the boat.
- the water is not moving, it could be perfectly still. It is the boat what moves.
- the pressure of the "stopped" sea water can't be lower than that of air on the cockpit, but it happens that the hole continues to suction air while the boat is moving.
Then it is not clear at all (for me) that this occurs by the "venturi effect".
Couldn't it be instead by the suction effect like when you have your hand flat on a table and then you separate the hand from the table very very quickly? (What's the name of this effect?).